The development of analytical methodology for simultaneous trace elemental analysis of blood plasma samples using total reflection X-ray fluorescence spectrometry

The development of a method for the direct determination of trace elements in blood plasma samples by TXRF through the use of chemical modifiers to compensate for analyte loss or sample modifications during the drying and matrix decomposition stages is described. A number of chemical modifiers [magnesium nitrate, nickel nitrate and ammonium pyrrolidinedithiocarbamate (APDC) coupled with magnesium nitrate] were investigated in combination with sample drying (infrared heat, vacuum and air drying) and thermal matrix decomposition techniques (ashing) to produce a suitable sample preparation methodology. Air drying of blood plasma;samples with the addition of APDC coupled with magnesium nitrate offered the most suitable method of analysis for the elements investigated (As, Br, Cd, Ca, Cl, Co, Cu, I, Fe, Pb, Mn, Mo, Ni, Se, Sn, Zn). A range of elemental concentrations (from 1 ng g(-1) to 270 mu g g(-1)) were observed for the blood plasma samples, which gave typical precisions of less than 8% RSD with corresponding recoveries of 90-100%.