Memory effects, plasma mass spectrometry

Al-Ammar,A., Gupta, R. K., and Barnes, R. M. (1999). Elimination of boron memory effect in inductively coupled plasma-mass spectrometry by addition of ammonia. Spectrochim. 

Da-Hai, S., Ren-Li, M.,McLeod, C.W., Xiao-Ru,W., and Cox,A. G. (2000). Determination of boron in serum, plasma and urine by inductively coupled plasma mass spectrometry (ICPMS). Use of mannitol-ammonia as diluent and for eliminating memory effect. J. Aml.At.Spectrom. 15(3), 257-262. 

Richter, R. C., Koirtyohann, S. R., and Jurisson, S. S. (1997). Determination of technetium-99 in aqueous solutions by inductively coupled plasma mass spectrometry Effects of chemical form and memory.]. Arml. At. Spectrom. 12(5), 557. 

Recent advances in multi-collector inductively-coupled plasma mass spectrometry (MC-ICPMS) techniques show promise, as this method allows bracketing of samples by standards, thus providing a means for near-simultaneous fractionation correction. Problems with this technique include memory effects (boron from previously analyzed samples or standards remobihzed during subsequent analyses), and extreme sensitivity to the solution matrix, requiring samples and standards to have identical matrices. 

Since the pioneering work by Gray (1975), mass spectrometry of elements ionized in an inductively coupled gas plasma at atmospheric pressure (ICP-MS) has gained a steadily increasing application for trace-element analysis. The determination of mercury by this technique seems to be quite free from interfering polyatomic mass fragments formed by constituents of the plasma and sample matrices, which may disturb the determination of elements with lower mass units (Houk, 1986 Delves, 1988 Lyon et al., 1988 Templeton et al., 1989 Olesik, 1991). However, especially in the case of mercury, several users of ICP-MS have experienced severe memory effects from samples with high mercury levels. 

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