title: A simple and rapid method for simultaneous determination of benzoic and sorbic acids in food using in-tube solid-phase microextraction coupled with high-performance liquid chromatography.
abstract: A simple, rapid and sensitive on-line method for the simultaneous determination of benzoic and sorbic acids in food was developed by coupling in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography (HPLC) with UV detection. The diethylamine-modified poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolithic capillary selected as the extraction medium exhibited a high extraction capability towards benzoic and sorbic acids. To obtain optimum extraction performance, several in-tube SPME parameters were investigated, including pH value, inorganic salt, and the organic solvent content of the sample matrix. After simple dilution with 0.02 mol/L phosphate solution (pH 4.0), carbonated drink, juice drink, sauce and jam samples could be directly injected for extraction. For succade samples, a small amount of acetonitrile was required to extract analytes prior to dilution and subsequent extraction. The linearity of the method was investigated over a concentration range of 5-20000 ng/mL for both analytes, and the correlation coefficients (R2 values) were higher than 0.999. The detection limits for benzoic and sorbic acids were 1.2 and 0.9 ng/mL, respectively. The method reproducibility was tested by evaluating the intra- and interday precisions; relative standard deviations of less than 4.4 and 9.9%, respectively, were obtained. Recoveries of compounds from spiked food samples ranged from 84.4 to 106%. The developed method was shown to be suitable for the routine monitoring of benzoic and sorbic acids in various types of food samples.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan, 430072, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wen
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Yu-Qi
authors.initials: YQ
authors.lastname: Feng
mesh_terms: D019817:Benzoic Acid / Q000032:analysis* / Q000302:isolation & purification; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D008722:Methods; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction; D013011:Sorbic Acid / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D019817:Benzoic Acid; D013011:Sorbic Acid