PubMed · 3503984
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J E Touhey, J C Davis, W T Workman. 1987. Hyperbaric oxygen therapy.. https://pubmed.ncbi.nlm.nih.gov/3503984/
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The applicability of trace enrichment and separation of microcontaminants on a single 10 x 2 mm I.D. high-pressure-packed liquid chromatography (LC) column, combined on-line with an atmospheric pressure chemical ionization (APCI)-ion-trap tandem mass spectrometry (MS-MS) instrument was studied for the target analysis of herbicides in river water. The total analysis time was 15-20 min. With the on-line short-column LC-MS-MS method, detection limits of 0.1-1 microgram/l can be achieved using only 4 ml of river water. However, the results obtained for a mixture of six triazines were considerably better than those for a mixture of eight phenylureas. An attempt is made to explain this difference on the basis of various processes that occur within the ion trap and the measurement procedure itself.
We describe the structure of a multi-atmospheric pressure ionisation (multi-API) interface for liquid chromatography-mass spectrometry (LC-MS). This interface includes five modes of atmospheric pressure spray with electron impact ionisation (APEI), atmospheric pressure chemical ionisation (APCI), atmospheric pressure spray ionisation (APSI), electrospray ionisation (ESI) and sonic spray ionisation (SSI). This LC-MS system was realised by developing an APEI interface which resembles other API interfaces and a highly sensitive API interface using advanced collision induced dissociation in a differential pumping region and an electrostatic ion guide. This system can deal with a wide variety of organic compounds from hydrocarbons with low polarity to proteins with high polarity by using the five modes.
A rapid and direct method for simultaneous determination of creatinine, creatine, and guanidinoacetic acid in biological samples has been developed by using column liquid chromatography-mass spectrometry (LC/APCI-MS). The determinations of creatinine, creatine, and guanidinoacetic acid in the samples of human urine and serum were carried out by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 93.87 +/- 6.00% (n = 5) for creatinine, 94.80 +/- 8.93% (n = 5) for creatine, and 90. 92 +/- 7.96% (n = 5) for guanidinoacetic acid after ion-exchange resin treatment. The content of creatinine in human urine and serum was also measured by the Jaffé method, a common method of determination of creatinine currently used in hospitals. The contents of creatinine, creatine, and guanidinoacetic acid obtained using LC/APCI-MS coincided well with those reported in previous papers.