Replicate determinations have been made on cyclohexane, carbon monoxide, and blood serum for traces (1-22 ng) of pyridine, dimethyl ether, and urea, respectively. The experiment employed single reaction monitoring to characterize the analyte with repetition rates of 15-51 samples per hour. Relative standard deviations were 5 to 15%.Double focusing mass spectrometers employ two analyzers which are coupled to achieve velocity focusing and, hence, high mass resolution. If the analyzers are uncoupled and scanned independently, they can be used to select specific reactant ions entering the inter-analyzer region and particular product ions leaving that region ( I , 2). This ability to specifically analyze for particular reactions has led to the development of the mass-analyzed ion kinetic energy spectrometer (MIKES) which records all the reactions of a particular ion in a single scan. This capability has been successfully applied to the direct analysis of specific components in complex mixtures (3, 4 ) . Implicit in the use of a mass analyzer as a separator in mass spectrometry/mass spectrometry (MS/MS) (5-11) is a time advantage over chromatographic alternatives. This paper seeks to demonstrate this feature explicitly.Speed of analysis is a particularly important consideration in the detection of trace amounts of carcinogens, pollutants, or impurities in complex mixtures where 110th high sample throughput and high sensitivity are required. The time required for analysis must include that used in sample preparation, viz., isolation, derivatization, and purification, as well as the requisite instrumental analysis time. Superior characteristics in this regard, and in sensitivity and compound specificity, have made gas chromatographyjmass spectrometry (GC/MS) the method of choice for trace organic analysis (12). Nevertheless, prechromatographic sample cleanup and derivatization of compounds may he complex and time-consuming, but successful application of GC/MS often demands this (12). In addition, the time required for a complete chromatographic separation of a mixture may be excessive, particularly when capillary columns are employed. A reduction in retention time may be realized by purification and isolation of the component of interest; however, because of the additional steps, overall analysis time may not decrease.Mass spectrometry/mass spectrometry (MS/MS) appears to have two advantages in rapid mixture analysis. First, it permits the analysis of complex mixtures with little or no sample pretreatment (3, 4, 13). Second, the primary separation performed in MS/MS is analogous to that in GC/MS but components are separated much more rapidly. Furthermore, any individual component can he selected a t any time during the analysis. This is to be contrasted with the sequential delivery of sample to the mass spectrometer in GC/MS. (This mode of separation has its own distinct advantages, including preconcentration of solutes from solvents and higher sample fluxes, albeit for shorter times.)Three chemical systems were investig...
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