PRINCETON APPLIED RESEARCH CORPORATION
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THE COMPLETE POTENTIOSTAT! The new PAR™ Potentiostat/Galvanostat provides more features, modes of operation and flexibility than ever before available. • Remote electrometer probe (mounted in signal cable) • 10 Π Π input impedance • Slewing rate: 10V//is • ^100 V compliance, 1 A max. • Two independent, internal potential sources • High speed electronic potential switching Plug-in modules provide maximum flexibility in readout. Positive feed- back IR compensation, high current measurement and galvanostatic capabilities up to 1 A are available. The Model 173 replaces a poten- tiostat. two voltage sources and a current-measuring device. Price of the Model 173 is $2200 including probe. Digital version, $2560. Current readout module, $145. I-E converter, $550. 100 raA output ver- sion less than $2000. For more data, contact Princeton Applied Research Corp., Box 565, Princeton, N.J. 08540; telephone (609) 452-2111. New Sulfur Dioxide Recorder Continuous sampling, Ultra portable, Under $1,000 New from Mast, the air monitoring specialist. Measures SO2 within EPA-specified ambient ranges. New selective electrode permits direct and immediate readings of SO2 in air with no significant interferences. Range is continuously variable from 0 to 0.2 ppm/vol. to 0 to 5 ppm/vol. Sensitivity is .005 ppm/vol. Integral strip chart recorder provides permanent data. For full details, send for Bulletin S-l. Ask about Mast low cost, portable Oxidant Monitors, too. The instruments with more than 12 years of field experience. MAST DEVELOPMENT COMPANY 2212 East 12th St., Davenport, la., 52803 (319) 326-0141 AIR MONITOH1NG DIVISION CIRCLE 109 ON READER SERVICE CARD 4 0 A . ANALYTICAL CHEMISTRY, VOL. 43, NO. 13, NOVEMBER 1971 chemical ionization," at the rela- tively high sample concentrations present in combined gas chromato- graph—chemical ionization mass spectrometers (56', 57). Preliminary results have been given on chemical ionization reac- tions with negative ions that suggest useful applications (58). Although chemical ionization mass spectrometry is associated with the transfer of massive par- ticles, the same instrumentation can be used to study charge exchange or electron transfer reactions at high pressures. The majority of charge exchange reactions which have been studied until recently have been studied at relatively low pressures in tandem instruments (59) or with the Cermak source (60). Experi- ments have been performed in a high-pressure source with several nonhydrogen-containing gases which produce charge; exchange spectra. The rare gases, N 2 , 0 2 , CO, CO,, KO, CF,, and CCL," have been tried (61). CO appears to be a particularly useful gas, giving spectra which contain both M+ and structurally useful fragment ions. The high-pressure charge exchange spectra of a few pesticides have been obtained and compared with their EI and CI spectra Hi). The charge exchange spectra are more nearly like conventional EI spectra than CI spectra and per- haps may be easier for mass spec- trometrists to interpret. The exist- ing correlations between structure and EI spectra may be useful in the interpretation of charge exchange spectra. The interpretation of chemical ionization spectra will be helped by a knowledge of acidic; solutions, but more structure-spec- tra correlations are needed. Acknowledgment The author is grateful to Noel Einolf and John Miehnowicz for their hell) in preparing this report. References (1) M. S. B. Munson and F. H. Field, J. Amer. Chcm. Sue, 88, 1621 (1966). (2) J. Miehnowicz and B. Munson, Org. Mas* Spectrum.. 4, 1S1 (1970). (3) J. H. Futrell and L. H. Wo.jeik, Rev. Sci. lustrum., 42, 244 (1971). (4) G. P. Arsonault. "Chemical Ionization Mass Spectrometry." in "Biochemical Applications of Mass Spectrometry," G. R. Waller, Ed.. Wiley-Interscienee. New York, N.Y., 1971 (in press). Report for Analytical Chemists PRINCETON APPLIED RESEARCH CORPORATION CIRCLE 1 3 7 O N READER SERVICE CARD
Transcript of PRINCETON APPLIED RESEARCH CORPORATION
THE COMPLETE POTENTIOSTAT! The n e w PAR™ Potentiostat/Galvanostat provides more features, modes of operation and flexibility than ever before available.
• Remote electrometer probe (mounted in signal cable)
• 10ΠΠ input impedance • Slewing rate: 10V//is
• ^100 V compliance, 1 A max. • Two independent, internal
potential sources • High speed electronic
potential switching Plug-in modules provide maximum flexibility in readout. Positive feedback IR compensation, high current measurement and galvanostat ic capabilit ies up to 1 A are available. The Model 173 replaces a poten-tiostat. two voltage sources and a current-measuring device. Price of the Model 173 is $2200 including probe. Digital version, $2560. Current readout module, $145. I-E converter, $550. 100 raA output version less than $2000. For more data, contact Princeton Applied Research Corp., Box 565, Princeton, N.J. 08540; te lephone (609) 452-2111.
New Sulfur Dioxide Recorder Continuous sampling, Ultra portable,
Under $1,000 New from Mast, the air monitoring specialist. Measures SO2 within EPA-specified ambient ranges. New selective electrode permits direct and immediate readings of SO2 in air with no significant interferences. Range is continuously variable from 0 to 0.2 ppm/vol. to 0 to 5 ppm/vol. Sensitivity is .005 ppm/vol. Integral strip chart recorder provides permanent data. For full details, send for Bulletin S-l. Ask about Mast low cost, portable Oxidant Monitors, too. The instruments with more than 12 years of field experience.
MAST DEVELOPMENT COMPANY 2212 East 12th St., Davenport, la., 52803 (319) 326-0141 AIR MONITOH1NG DIVISION
CIRCLE 109 ON READER SERVICE CARD
4 0 A . ANALYTICAL CHEMISTRY, VOL. 43 , NO. 13, NOVEMBER 1971
chemical ionization," at the relatively high sample concentrations present in combined gas chromato-graph—chemical ionization mass spectrometers (56', 57).
Preliminary results have been given on chemical ionization reactions with negative ions tha t suggest useful applications (58).
Although chemical ionization mass spectrometry is associated with the transfer of massive particles, the same instrumentation can be used to study charge exchange or electron transfer reactions at high pressures. The majority of charge exchange reactions which have been studied until recently have been studied at relatively low pressures in tandem instruments (59) or with the Cermak source (60). Experiments have been performed in a high-pressure source with several nonhydrogen-containing gases which produce charge; exchange spectra. The rare gases, N2 , 0 2 , CO, CO,, KO, C F , , and CCL," have been tried (61). CO appears to be a particularly useful gas, giving spectra which contain both M+ and structurally useful fragment ions. The high-pressure charge exchange spectra of a few pesticides have been obtained and compared with their E I and CI spectra Hi).
The charge exchange spectra are more nearly like conventional E I spectra than CI spectra and perhaps may be easier for mass spec-trometrists to interpret. The existing correlations between structure and EI spectra may be useful in the interpretation of charge exchange spectra. The interpretation of chemical ionization spectra will be helped by a knowledge of acidic; solutions, but more structure-spectra correlations are needed.
Acknowledgment The author is grateful to Noel
Einolf and John Miehnowicz for their hell) in preparing this report.
References (1) M. S. B. Munson and F. H. Field, J.
Amer. Chcm. Sue, 88, 1621 (1966). (2) J. Miehnowicz and B. Munson, Org.
Mas* Spectrum.. 4, 1S1 (1970). (3) J. H. Futrell and L. H. Wo.jeik, Rev.
Sci. lustrum., 42, 244 (1971). (4) G. P. Arsonault. "Chemical Ionization
Mass Spectrometry." in "Biochemical Applications of Mass Spectrometry," G. R. Waller, Ed.. Wiley-Interscienee. New York, N.Y., 1971 (in press).
Report for Analytical Chemists
PRINCETON APPLIED RESEARCH CORPORATION
CIRCLE 137 O N READER SERVICE CARD
