http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&feed=atom&action=history FAQs AMS Data Analysis - Revision history 2024-03-28T15:06:42Z Revision history for this page on the wiki MediaWiki 1.30.0 http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8365&oldid=prev Jose: /* I have weird ions that have strange shapes and don't make sense chemically, what's going on? */ 2011-03-22T17:56:20Z <p>‎<span dir="auto"><span class="autocomment">I have weird ions that have strange shapes and don&#039;t make sense chemically, what&#039;s going on?</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 17:56, 22 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l77" >Line 77:</td> <td colspan="2" class="diff-lineno">Line 77:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">** Power point on V, W and VW ions from Pete Decarls, Toronto User's Meeting [http://cires.colorado.edu/jimenez-group/UsrMtgs/UsersMtg10/DeCarlo_VWVWions.pdf here]</del></div></td><td colspan="2">&#160;</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The dromedaires and volkswagens can be reduced by tuning the mass spectrometer</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The dromedaires and volkswagens can be reduced by tuning the mass spectrometer</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* They will be proportional to your mass spectrum, so in most cases you will see the N2+ and O2+ ions in diff, but showing at strange times-of-flight, and with strange (broad, asymmetrical) shapes. However if you have very large aerosol signals, the large ions may be visible as well</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* They will be proportional to your mass spectrum, so in most cases you will see the N2+ and O2+ ions in diff, but showing at strange times-of-flight, and with strange (broad, asymmetrical) shapes. However if you have very large aerosol signals, the large ions may be visible as well</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* For further details on these ions, see the presentation from Pete Decarlo, Toronto User's Meeting [http://cires.colorado.edu/jimenez-group/UsrMtgs/UsersMtg10/DeCarlo_VWVWions.pdf here]</ins></div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* This is separate from doubly-charged ions, which have normal shapes, but can appear at half-masses, e.g. doubly-charged pyrene can appear at m/z 101 (vs. a MW of 202 for pyrene). See e.g. Dzepina et al., IJMS 2007 for examples with PAHs.</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* This is separate from doubly-charged ions, which have normal shapes, but can appear at half-masses, e.g. doubly-charged pyrene can appear at m/z 101 (vs. a MW of 202 for pyrene). See e.g. Dzepina et al., IJMS 2007 for examples with PAHs.</div></td></tr> </table> Jose http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8364&oldid=prev Dfarmer: /* I have weird ions that have strange shapes and don't make sense chemically, what's going on? */ 2011-03-22T17:43:35Z <p>‎<span dir="auto"><span class="autocomment">I have weird ions that have strange shapes and don&#039;t make sense chemically, what&#039;s going on?</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 17:43, 22 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l77" >Line 77:</td> <td colspan="2" class="diff-lineno">Line 77:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>** Power point on V, W and VW ions from Pete Decarls, Toronto User's Meeting [<del class="diffchange diffchange-inline">here </del>http://cires.colorado.edu/jimenez-group/UsrMtgs/UsersMtg10/DeCarlo_VWVWions.pdf]</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>** Power point on V, W and VW ions from Pete Decarls, Toronto User's Meeting [http://cires.colorado.edu/jimenez-group/UsrMtgs/UsersMtg10/DeCarlo_VWVWions.pdf <ins class="diffchange diffchange-inline">here</ins>]</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td></tr> </table> Dfarmer http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8362&oldid=prev Dfarmer: /* I have weird ions that have strange shapes and don't make sense chemically, what's going on? */ 2011-03-22T17:43:03Z <p>‎<span dir="auto"><span class="autocomment">I have weird ions that have strange shapes and don&#039;t make sense chemically, what&#039;s going on?</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 17:43, 22 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l77" >Line 77:</td> <td colspan="2" class="diff-lineno">Line 77:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">** Power point on V, W and VW ions from Pete Decarls, Toronto User's Meeting [here http://cires.colorado.edu/jimenez-group/UsrMtgs/UsersMtg10/DeCarlo_VWVWions.pdf]</ins></div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* The camels can be removed by turning the hard mirror</div></td></tr> </table> Dfarmer http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8358&oldid=prev Jose: /* How do you account for variable CO2 in the sampled air during analysis ? */ 2011-03-22T17:29:27Z <p>‎<span dir="auto"><span class="autocomment">How do you account for variable CO2 in the sampled air during analysis ?</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 17:29, 22 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l70" >Line 70:</td> <td colspan="2" class="diff-lineno">Line 70:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* For other gas-phase species such as CO, N2O, CH4, at their typical ambient concentrations they produce too small of a signal to see it in the AMS. If you are sampling air with large concentrations of those gases (at least tens of ppmv), then you can apply the same principles described above for gas-phase CO2.</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* For other gas-phase species such as CO, N2O, CH4, at their typical ambient concentrations they produce too small of a signal to see it in the AMS. If you are sampling air with large concentrations of those gases (at least tens of ppmv), then you can apply the same principles described above for gas-phase CO2.</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">== I have weird ions that have strange shapes and don't make sense chemically, what's going on? ==</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* This can happen on the HR-ToF-AMS due to interactions within the V and W modes</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">** If you forget to turn off the hard mirror when you are in V mode, you can have some ions that followed a W path (&quot;W ions in V&quot; or &quot;camels&quot;)</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">** You can also have ions in W mode which have followed a V path (&quot;V ions in W&quot; or &quot;dromedaires&quot;)</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">** You can also have ions in W mode which have gone through the hard mirrow twice and through the reflectron 3 times (&quot;VW ions in W&quot;, or &quot;volkswagens&quot;)</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* The camels can be removed by turning the hard mirror</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* The dromedaires and volkswagens can be reduced by tuning the mass spectrometer</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* They will be proportional to your mass spectrum, so in most cases you will see the N2+ and O2+ ions in diff, but showing at strange times-of-flight, and with strange (broad, asymmetrical) shapes. However if you have very large aerosol signals, the large ions may be visible as well</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* This is separate from doubly-charged ions, which have normal shapes, but can appear at half-masses, e.g. doubly-charged pyrene can appear at m/z 101 (vs. a MW of 202 for pyrene). See e.g. Dzepina et al., IJMS 2007 for examples with PAHs.</ins></div></td></tr> </table> Jose http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8343&oldid=prev DonnaS: /* Example of interferences: frag_CO2[44] */ 2011-03-20T15:55:57Z <p>‎<span dir="auto"><span class="autocomment">Example of interferences: frag_CO2[44]</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:55, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l40" >Line 40:</td> <td colspan="2" class="diff-lineno">Line 40:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The AMS measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get an aerosol-only measurement. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions. <del class="diffchange diffchange-inline"> </del>See below for further details.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The AMS measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get an aerosol-only measurement. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions. <ins class="diffchange diffchange-inline">If an external gas phase CO2 measurement is available, one can use a time-dependent frag entry to account for changing gas phase CO2 contributions. </ins>See below for further details.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td></tr> </table> DonnaS http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8342&oldid=prev DonnaS: /* Example of interferences: frag_CO2[44] */ 2011-03-20T15:53:54Z <p>‎<span dir="auto"><span class="autocomment">Example of interferences: frag_CO2[44]</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:53, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l40" >Line 40:</td> <td colspan="2" class="diff-lineno">Line 40:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The AMS measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get aerosol-only <del class="diffchange diffchange-inline">signal</del>. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The AMS measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get <ins class="diffchange diffchange-inline">an </ins>aerosol-only <ins class="diffchange diffchange-inline">measurement</ins>. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td></tr> </table> DonnaS http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8341&oldid=prev DonnaS: /* Example of interferences: frag_CO2[44] */ 2011-03-20T15:53:01Z <p>‎<span dir="auto"><span class="autocomment">Example of interferences: frag_CO2[44]</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:53, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l40" >Line 40:</td> <td colspan="2" class="diff-lineno">Line 40:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The AMS <del class="diffchange diffchange-inline">aerosol </del>measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get aerosol-only signal. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The AMS measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get aerosol-only signal. Frag_CO2 indicates the amount of gas phase CO2 that was measured.&#160; It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td></tr> </table> DonnaS http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8340&oldid=prev DonnaS: /* Example of interferences: frag_CO2[44] */ 2011-03-20T15:52:34Z <p>‎<span dir="auto"><span class="autocomment">Example of interferences: frag_CO2[44]</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:52, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l40" >Line 40:</td> <td colspan="2" class="diff-lineno">Line 40:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Frag_CO2 indicates the amount of gas phase CO2 that was measured. It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The AMS aerosol measurement has an interference due to gas phase signal. Because we know gas phase atmospheric composition well, we can subtract the gas phase contribution from the total signal to get aerosol-only signal. </ins>Frag_CO2 indicates the amount of gas phase CO2 that was measured. <ins class="diffchange diffchange-inline"> </ins>It has been isolated from the frag_air wave to highlight it's importance and necessity of adjustment. The default frag_CO2 wave has only one contribution: frag_CO2[44] = 0.00037*1.12588*1.28*1.14*frag_air[28]. This example also highlights the syntactical use of multiple factors to help remind users of the formula derivation. Frag_air[28] corresponds to N2 signal, the largest signal measured. The default frag table entry indicates that the amount of CO2 expected is a linear multiple of the amount of N2 that is measured. The factor 1.12588*1.28*1.14 are factors that account for the relative ionization efficiency of CO2 (w.r.t. to nitrate), the ratio of nitrogen/air, and an empirical factor to mainly account for the better focusing of CO2 (vs. N2) on the molecular beam formed at the exit of the lens (plus any other effects such as small differences in ion transmission efficiency). The first factor, 0.00037 roughly corresponds to expected ambient CO2 gas phase levels of 370ppm.&#160; The amount of gas phase CO2 detected in the ambient sample can change significantly with location and time of year, and so this is one of the entries that requires the user to adjust the default values to correctly reflect sampling conditions.&#160; See below for further details.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of estimation of an ion from a typical fragmentation pattern: frag_org[64] ====</div></td></tr> </table> DonnaS http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8339&oldid=prev DonnaS: /* Example of isotopes: frag_K[41] from frag_K[39] */ 2011-03-20T15:34:56Z <p>‎<span dir="auto"><span class="autocomment">Example of isotopes: frag_K[41] from frag_K[39]</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:34, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l35" >Line 35:</td> <td colspan="2" class="diff-lineno">Line 35:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of isotopes: frag_K[41] from frag_K[39] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of isotopes: frag_K[41] from frag_K[39] ====</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The default frag_K has only two contributions (two non-blank entries): frag_K[39]=39 and 0.0722*frag_K[39]. This means that all of the signal at m/z 39 is <del class="diffchange diffchange-inline">due </del>to potassium <del class="diffchange diffchange-inline">and a </del>small fraction, the isotopic fraction 41K to 39K should exist at m/z 41. The naturally occurring fractional percents of K are: 41K=93.2581, 40K=0.0117 and 39K=6.7302. To calculate the amount of 41K we should see from 39K we get 6.7302/93.2581 = 0.0721675 ~=0.0722.&#160; The frag table does not consider the isotope for 40K because it is thought to be too small to matter.&#160; As an aside, for almost all cases, the potassium signal is due to an instrumental artifact and is not due to aerosol.&#160; &#160;</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The default frag_K has only two contributions (two non-blank entries): frag_K[39]=39 and 0.0722*frag_K[39]. This means that all of the signal at m/z 39 is <ins class="diffchange diffchange-inline">apportioned </ins>to potassium<ins class="diffchange diffchange-inline">. A </ins>small fraction, the isotopic fraction 41K to 39K should exist at m/z 41. The naturally occurring fractional percents of K are: 41K=93.2581, 40K=0.0117 and 39K=6.7302. To calculate the amount of 41K we should see from 39K we get 6.7302/93.2581 = 0.0721675 ~=0.0722.&#160; The frag table does not consider the isotope for 40K because it is thought to be too small to matter.&#160; &#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>&#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>As an aside, for almost all cases, the potassium signal is due to an instrumental artifact and is not due to aerosol.&#160; <ins class="diffchange diffchange-inline">For most cases the assumption that all of the signal at 39 is due to K is an approximation; if the instrument is a V/W ToF, one should examine masses at m/z 39 to test this assumption. When examining m/z 39 in Pika, it one should be aware that surface ionization will show a different peak shape than for ionization of atmospheric aerosols.</ins></div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of interferences: frag_CO2[44]====</div></td></tr> </table> DonnaS http://cires1.colorado.edu/jimenez-group/wiki/index.php?title=FAQs_AMS_Data_Analysis&diff=8338&oldid=prev DonnaS: /* Types of frag table entries */ 2011-03-20T15:28:53Z <p>‎<span dir="auto"><span class="autocomment">Types of frag table entries</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 15:28, 20 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l29" >Line 29:</td> <td colspan="2" class="diff-lineno">Line 29:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=== Types of frag table entries ===</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=== Types of frag table entries ===</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">* </del>The frag table entries accounts for isotopes, interferences from other species, and empirically-measured fragmentation.&#160; For new or beginning users, the array of values within the frag table can be overwhelming, but all entries are due to three types of contributions: isotopes (one entry is a isotopic fraction of another), interferences (several species contribute to the same m/z) and fragmentation (the breaking up of the non-ionized entity into patterns of often smaller ions). &#160;</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The frag table entries accounts for isotopes, interferences from other species, and empirically-measured fragmentation.&#160; For new or beginning users, the array of values within the frag table can be overwhelming, but all entries are due to three types of contributions: &#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* </ins>isotopes (one entry is a isotopic fraction of another), &#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* </ins>interferences (several species contribute to the same m/z) and &#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* </ins>fragmentation (the breaking up of the non-ionized entity into patterns of often smaller ions). &#160;</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of isotopes: frag_K[41] from frag_K[39] ====</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Example of isotopes: frag_K[41] from frag_K[39] ====</div></td></tr> </table> DonnaS