High-Accuracy Determination of Potassium and Selenium in Human Serum by Two-Step Isotope Dilution ICPMS

Abstract

A high-accuracy measurement technique for determining potassium and selenium in human serum was developed by using two-step Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ICPMS) in this research. A more accessible method of the quadrupole ICPMS was employed in this research to achieve an equally high accuracy which had been achieved by a much more expensive method, namely, high-resolution sector field ICPMS (SF-ICPMS), with a comparatively easy and simple operation. In addition, we have evaluated the uncertainty of this method. The results showed that the determination limits of potassium and selenium in serum were 0.8 mg/kg and 2.7 μg/kg, respectively, and the precision for both measurements was lower than 0.2% and 0.7%. The measurement, when employed to measure potassium and selenium in standard materials NIST956D, NIST909C, and GBW09152, had caused a maximum deviation of less than 0.9%, within the stated uncertainty range of standard materials. The RELA international inter-laboratory comparisons of potassium in serum in 2018 conducted by our laboratory also yielded a satisfactory result.

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…A strategy to simplify a reference ICP-MS method for the determination of K and Se in human serum to make it more accessible for laboratories with standard ICP-QMS equipment followed a two-step ID procedure, which in contrast to conventional ID obviates the need to accurately pre-determine the concentration of the enriched isotope in the ID spike by SF-ICP-MS. 77 Interferences were removed using the less common reaction gas CH 4 . The method achieved LODs of 0.8 mg kg −1 and 2.7 μg kg −1 for K and Se, respectively, RSDs were <0.2 and <0.7% and deviations from certified values were <0.9% in human serum SRMs.…”

Measurement of Magnesium, Zinc, and Copper in Human Serum by Using Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID ICP-MS)

“…Tis isotope dilution mass spectrometry originated from the UK Government Chemist Laboratory (GCL) [9,10]. We have established isotope dilution mass spectrometry for the detection of potassium and selenium in human serum using this principle [11]. Compared with conventional isotope dilution mass spectrometry, it has the advantage of not having to calibrate the concentration of the isotopic spike during the standardization process.…”