Mass spectrometric detection effluent

Lacorte, S., Perrot, M. C., Fraisse, D., and Barcel6, D., Determination of chlorobenzidines in industrial effluent by solid-phase extraction and liquid chromatography with electrochemical and mass spectrometric detection, J. Chromatogr. A, 833, 181-194, 1999. 

Mass Spectrometric Detection. The very small volumetric flow rates of less than 1 pi,/min from electrophoresis capillaries make it feasible to couple the effluent directly to the Ionization source of a mass spectrometer. The most common sample-introduction and ionization interface for this purpose is currently electrospray (Section 20B-4), although fast atom bombardment, matrix-assisted laser desorption-ionization (MALDI) spectrometry, and inductively coupled plasma mass spectrometry (ICPMS) have also been used. Because the liquid sample must be vaporized before entering the mass spectrometry (MS) system. 

Mass Spectrometric Detection for SFC. The advantages of coupling a chromatographic technique with mass spectrometry are considerable, as evidenced by the major role of GC-MS in mixture analysis. However, in contrast to GC, where the effluent is compatible with classical gas phase ionization methods, the ideal approach to interfacing SFC or HFLC with mass spectrometry is not immediately obvious. 

A similar mass spectrometric detection system is available commercially and is realized by a multiplexing electrospray inlet in combination with a time-of-flight (TOF) mass spectrometer that has a sufficiently high data acquisition rate. Like the above-described optical switch, the effluent of the HPLC channels is nebulized in individual probe tips and sprayed toward a rotating cylinder with a slit. By stepping this slit very rapidly from one probe tip to another, again a data acquisition rate of approximately one spectrum per channel can be reached in 1 second. Unlike the multiplex PDA detector, this multiplex mass spectrometric detector is normally connected to a HPLC system by a flow splitter. ... 

Mass spectrometric detection allows analysis of most nonionic surfactants without deriva-tization. Thermospray, electrospray, or atmospheric pressure chemical ionization interfaces permit direct introduction of the effluent of the LC into the MS and make the MS a very selective detector for nonionics. Quasimolecular ions are produced for each discrete compound, so that the HPLC system is not required to separate both by degree of ethoxylation and by alkyl character. A relatively simple HPLC separation, coupled with MS anal-... 

Degradative methods based on pyrolysis are the subject of renewed interest due to the identification power offered by gas chromatography-mass spectrometric systems (GC-MS) (Wershaw and Bohner, 1969 Martin et al., 1977 Meuzelaar et al., 1977 Bracewell and Robertson, 1976). There are two main pyrolysis techniques (1) controlling the decomposition kinetics by temperature programming and (2) the use of quasi-instantaneous heating (e.g.. Curie point pyrolysis). The later technique avoids most recombination reactions, but does not allow kinetic control. The pyrolysis effluent can be detected directly (Rock-Eval method) or after chromatographic fractionation. 

Names rejected by the ICTA committee were effluent gas detection, effluent gas analysis, thermovaporimetric analysis, and thermohygrometric analysis. Also, terms such as mass spectrometric thermal analysis (MTA) and mass spectrometric differential thermal analysis (MDTA) should be avoided. Unfortunately, new names for the techniques are constantly being created, such as thermal evolution analysis (TEA). The technique of TEA, according to Chiu (18), includes all techniques that monitor continuously the amount of volatiles thermally evolved from the sample upon programmed heating. 

---