Analysis of sweat chloride by reversed phase high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) method for the determination of sweat chloride was developed and evaluated. This method is capable of measuring chloride ion in sweat eluates with an analytical working range from 0.5 mmol/L to 6 mmol/L (15 to 180 mmol/L in undiluted sweat samples). Precision studies showed that at the levels of 1 mmol/L, 2.5 mmol/L and 3.5 mmol/L, the within batch coefficients of variation were 1.26%, 0.88% and 0.43%, respectively, and the between batch coefficients of variation were 1.31%, 1.75% and 1.07%, respectively. The minimum detection limit was 0.5 mmol/L. This method correlated well with the ion-selective electrode (ISE) method currently in use.