A. Al-ammar et al., Simultaneous sample preconcentration and matrix removal using field-flow fractionation coupled to inductively coupled plasma mass spectrometry, SPECT ACT B, 56(10), 2001, pp. 1951-1962
An on-channel sample pre concentration-matrix removal arrangement, based on
coupling field-flow fractionation (FFF) to inductively coupled plasma mass
spectrometry (ICP-MS), has been constructed for on-line sample pretreatmen
t ICP-MS trace element determination. A commercial FFF system is modified t
o incorporate an on-channel preconcentration procedure allowing injection o
f up to 50 ml of sample, which could be preconcentrated by 50-1400 fold. A
high molecular weight complexing agent added to the sample forms strong com
plexes with the measured trace analytes but not with the sample matrix. Whe
n the sample-complexing agent mixture is introduced to the FFF unit, the un
complexed matrix element is removed by permeation through a membrane that s
eparates the FFF sample compartment. The trace analytes remain in the FFF c
hannel, because their high molecular weight complexes do not permeate throu
gh the membrane. Pre concentration and matrix elimination occur simultaneou
sly. The matrix-free, preconcentrated sample is introduced directly to the
ICP-MS nebulizer. The method was tested using 10-ml sample aliquots that co
ntain As, Cd, Cu, Mo, Pb, Re, Sn, Te, TI, Y, Zn and Zr analytes and 5000 mg
l(-1) Ca or Na matrices and ethylene imine polymer complexing agent. Coppe
r and Re isotopic ratio values in reference standards also were determined
after preconcentration and matrix element removal. (C) 2001 Elsevier Scienc
e B.V. All rights reserved.