Liquid chromatography plasma source detection

Bayliss M. Little D. Mallett D. Plumb R. Parallel ultra-high flow rate liquid chromatography with mass spectrometric detection using a multiplex electrospray source for direct, sensitive determination of pharmaceuticals in plasma at extremely high-throughput. Rapid Communications in Mass Spectrometry, 2000, 14, 2039-2045. 

SFC has received attention as an alternative separation technique to liquid and gas chromatography. The coupling of SFC to plasma detectors has been studied because plasma source spectrometry meets a number of requirements for suitable detection. There have been two main approaches in designing interfaces. The first is the use of a restrictor tube in a heated cross-flow nebuliser. This was designed for packed columns. For a capillary system, a restrictor was introduced into the central channel of the ICP torch. The restrictor was heated to overcome the eluent freezing upon decompression as it left the restrictor. The interface and transfer lines were also heated to maintain supercritical conditions. Several speciation applications have been reported in which SFC-ICP-MS was used. These include alkyl tin compounds (Oudsema and Poole, 1992), chromium (Carey et al., 1994), lead and mercury (Carey et al., 1992), and arsenic (Kumar et al., 1995). Detection limits for trimethylarsine, triphenylarsine and triphenyl arsenic oxide were in the range of 0.4-5 pg. 

Bayliss, M.K. Little, D. Mallett, D.N. Plumb W.S. Parallel Ultra-high Plow Rate Liquid Chromatography with Mass Spectrometric Detection Using a Multiplex Electrospray Source for Direct, Sensitive Determination of Pharmaceuticals in Plasma at Extremely High Throughput, Rapid Commun. Mass Spectrom. 14, 2039-2045 (2000). 

Wotiz and Chattoraj (Wll) studied the specificity, accuracy, sensitivity, adaptability, and the sources of error in the analysis of estrogens using thin-layer and gas-liquid chromatography. Their method permits the determination of as little as 0.2 j g of estrogen per 24 hours. Free estrone in blood plasma has been determined by Attal, Hendeles, and Eik-Nes (AlO) using GLC with electron-capture detection. GLC was used by Ruchelman (R3) in solubility studies of estrone in organic solvents. 

This chapter reviews and expands on the material presented by the authors at the 1987 Eastern Analytical Symposium. A short review of the work done in this area by other researchers will be presented for completeness. The primary focus will be on chromatographic sample introduction for plasma source MS. The use of ICP-MS for the detection of high performance liquid chromatography (HPLC) eluates will be discussed. Speciation of several As and Sn compounds found in the environment demonstrates the ability of ICP-MS to provide element specific detection at ultra-trace levels. In addition, gas chromatographic detection using He microwave-induced plasma mass spectrometry (MIP-MS) is shown to be a promising technique, particularly for the determination of halogenated species. 

---