Analysis of whole blood by ICP-MS equipped with a high temperature total sample consumption system

Abstract

In this work, the performance of a high temperature torch Integrated Sample Introduction System (hTISIS) using inductively coupled plasma mass spectrometry (ICP-MS) for the multi-element analysis of whole blood is evaluated. Two different quadrupole-based spectrometers were tested and the optimization studies were performed with a reference whole blood material. Sample dilution factor and hTISIS temperature were taken as the variables. The sample was introduced following two different procedures: continuous aspiration and air-segmentation. The optimum performance of the system in terms of both analytical figures of merit and accuracy was obtained for a hTISIS temperature of 200 °C and for either 1 : 10 or 1 : 25 dilution factors depending on the ICP-MS device used. An improvement in terms of sensitivity and detection limits was obtained with the hTISIS as compared to the conventional cyclonic spray chamber. Thus, for 1 : 25 diluted blood samples, the hTISIS improved the sensitivity by a factor ranging 2.0–4.5. Moreover, at 200 °C, the limits of detection for hTISIS at 200 °C were 1.1 to 8.4 times lower than those for the cyclonic spray chamber. This analytical parameter was in the ng L⁻¹ range for the detected elements. Matrix effects in turn became less severe as the hTISIS temperature increased (from room temperature to 80 °C). All these results were obtained without a severe degradation of the fundamental plasma parameters. In fact, under optimum conditions BaO⁺/Ba⁺ and Ba²⁺/Ba⁺ signal ratios were 1.2% and 2.0%, respectively. The developed method was applied for the analysis of low volumes (ca. 2.5 μL) of real blood samples after a minimally invasive collection by volumetric absorptive microsampling. The hTISIS is an easy-to-implement sample introduction system that can be employed for the routine analysis using ICP-MS.