Comparison of the CETAC MVX‐7100 Micro‐Volume Workstation with an Established Laboratory Method for the Assessment of Lead, Mercury, and Arsenic in Human Whole Blood

INTRODUCTION Conventional autosamplers used in clinical ICP‐MS are largely based on the needs of non‐clinical environments. Their disadvantages are numerous and include high sample volume consumption, large dead volumes resulting in wasted sample, and the inability to integrate easily with high throughput formats such as 96 and 384 well plates. Further, use of a low‐volume autosampler allows for a reduction in reagents translating into an overall reduction in costs.

METHODS

Use of clinical samples

This project and its protocols were approved by the University of Utah Institutional Review Board (IRB #00007275).

Instrumentation

The established laboratory method uses a Perkin Elmer 9000 (lead, mercury, cadmium, arsenic screen) and a Perkin Elmer DRC II (arsenic hydride

confirmation).  Standard addition was used for calibration with no weighting and the origin ignored. A representative pool sample was analyzed and subtracted out by the PerkinElmer software to correct for the unfortified fraction of each element in the pool.

The MVX‐7100 method was conducted using an Agilent 7700x (Agilent Technologies, Santa Clara, CA). Lead and mercury were analyzed in standard mode while arsenic was analyzed using the Octopole Reaction System at 4.5L/min of helium gas. Standard addition was used for calibration with 1/x weighting and the origin ignored. No calibration or reagent blank was used in the data analysis and the low standard was set as the internal standard reference file. 

Working calibrator preparation

Four concentrations of calibrators were prepared containing mercury, lead and arsenic. Goat whole blood was fortified with an amount of each analyte from stock solutions (Inorganic Ventures, Christiansburg, VA) to obtain the concentrations listed in Table 1.