Ion chromatography as candidate reference method for the determination of chloride in human serum

Abstract

Background: We developed an ion chromatography (IC) method for measurement of chloride in human serum which was regarded as a simple, rapid, accurate, and sensitive technique. The method will be hopefully selected as a candidate reference method. Method: Serum aliquots of 0.1 mL were diluted 500 times with Milli-Q water, and chloride in serum samples was measured by IC with a gradient elution procedure using a KOH eluent generator. Results: Based on the data, chloride in human serum was well detected by IC. The calibration curve for chloride was linear in the concentration range from 0 to 0.42 mmol/L with a correlation coefficient of.99995 under the optimum experimental conditions. The chloride concentration had a good linear relationship with the peak areas of chloride. This method was sensitive because of the low limit of detection (LOD) and the low limit of quantification (LOQ) 9.87 × 10−5 mmol/L and 3.27 × 10−4 mmol/L, respectively. Besides, the method was highly precise with the within-run coefficient of variations (CVs) for the measurement of low, medium, and high concentration level samples 0.32%, 0.73%, and 0.50%. As for the evaluation of accuracy, the biases were less than ±1% and 2% by comparing with National Institute of Science and Technology (NIST) standard material SRM 956d and 2013-2018 IFCC-RELA samples, respectively. Finally, the biases between IC method and the inductively coupled plasma mass spectrometry (ICP-MS) method were less than 1% which showed good agreement. Conclusion: Ion chromatography is a simple sample treatment procedure for the determination of chloride in human serum with high sensitivity and specificity. The proposed method could be recommended as a candidate reference method for the determination of serum chloride in human serum.