An improved candidate reference method for serum potassium measurement by inductively coupled plasma-mass spectrometry

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• 作者：Rui Zhang¹ ; Huaian Ma¹ ; Huiling Li ; Jing Xu ; Jianping Zhang ; Yang Zhang ; Qingtao Wang ; ^{wqt36@163.com}
• 关键词：Serum ; Potassium ; Cobalt ; Inductively coupled plasma-mass spectrometry (ICP-MS) ; Reference method
• 刊名：Clinica Chimica Acta
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：420
• 期：Complete
• 页码：146-149
• 全文大小：154 K

文摘

Background

In 2002, the National Institute of Standards and Technology (NIST) established a reference method for serum potassium based on inductively coupled plasma-mass spectrometry (ICP-MS). The aim of this study was to develop an inexpensive and improved candidate reference method for accurate and precise determination of serum potassium.

Methods

Serum samples were diluted with 1 % HNO₃ supplemented with ⁵⁹Cobalt as isotope internal standard, and potassium was measured by ICP-MS. The new method was evaluated with NIST standard reference materials (SRMs), according to the Clinical and Laboratory Standard Institute's evaluation protocols.

Results

At 4.300 and 4.678 mmol/l levels, the present method demonstrated analytical imprecision of 0.09 % and 0.14 % , and recoveries of 99.67 % to 99.88 % , respectively. The bias between the target values of SRMs were ? 0.02 % to + 0.28 % , respectively. This method was linear between 0.0000 and 6.87 mmol/l (R² = 1.000). The method had an uncertainty (U_{95 %} ) of 0.76 % .

Conclusions

The proposed ICP-MS method to measure serum potassium is precise and accurate, with high sensitivity and specificity. It may be considered as a candidate reference method for the determination of serum potassium.