Determination Of Carbohydrates And Sugar Alcohol In Infant Formula By Ion Chromatography With Pulsed Amperometric Detection And An Optimized Gradient Elution

A method was developed for the determination of carbohydrates and sugar alcohol related closely to metabolic diseases in infant formula, including maltitol, galactose, glucose, sucrose, fructose and lactose, by ion chromatography (IC) with pulsed amperometric detection and an optimized gradient elution. The developed method included the systematic optimizations of sample pre-treatment, column selection and gradient elution. And more attention has been paid to optimizing the gradient elution program. According to the chromatographic behavior of the targets, the total gradient elution was divided into four subprograms, including separation of the analytes with weaker retentions, separation of lactose, matrix elimination and system equilibrium, and each part was also optimized in detail. By the optimized gradient elution, both negative chromatographic phenomena of overlapping between analytes with weak retentions and tailing for lactose were eliminated well, and all of the analytes were separated completely. Both maltitol and galactose were fitted well with quadratic curve, and the others were fitted well with linear equation, with the correlation coefficients (r) greater than 0. 99, in the con. centration range of 0. 5-100 mg/L, with the limits of detection (LODs) (S/N = 3) of 0. 06- 0. 40 mg /L. The developed method offered a helpful method for gradient elution optimization, and it had been used for the determination of the real samples. It was proved to be feasible for routine analysis.