应用离子对反相高效液相色谱法测定了不同基质样品中亚硫酸盐的含量.不同样品中的亚硫酸根先后用稀盐酸及山梨醇的混合溶液和乙酸钠及山梨醇的混合溶液提取,并离心分离,所得上清液中的亚硫酸根与甲醛反应生成羟甲基磺酸盐(HMS)而使之固定.用Venusil MP C18柱作固定相,并用三乙基辛烷膦酸铵(pH 5.0)溶液与甲醇以9比1(体积比)混合所得溶液作流动相对试液进行离子对色谱分离.在柱后衍生系统中,分出的HMS先与氢氧化钾作用而重新释出亚硫酸根阴离子,再与5,5-二巯基-2,2-二硝基苯甲酸进行衍生反应,生成5-巯基-2-硝基-苯甲酸,对此产物在450 nm波长处进行分光光度检测,方法的检出限(3S/N)为0.15 mg·L-1.用标准加入法进行回收试验,测得回收率在85.9%~105.2%之间.

Ion-pair RP-HPLC was applied to the determination of sulfite in samples of different matrixes.Sulfite in different sample was extracted with mixed solution of dil.HCl and sorbitol and with mixed solution of NaOAc and sorbitol in succession,and separated by centrifugation.Free sulfite anion in the supernatant was fixed by reacting with formaldehyde to form hydroxymethyl sulfonate (HMS),which was separated on the Venusil MP-C18 column with mixed solution of ammonium triethyloctane phosphonate solution (pH 5.0) and methanol (mixed in the ratio of 9 to 1 by volume) as mobile phase.In the post derivatization system,HMS was reacted first with KOH to regenerate SO2-3 and then derivatized with 5,5-dimercapto-2,2-dinitrobenzoic acid to give 5-mercapto-2-nitrobenzoic acid,which was detected at 450 nm spectrophotometrically.Detection limit (3S/N) of the method was found to be 0.15 mg·L-1.Test for recovery was made by standard addition method,values of recovery were found in the range of 85.9%-105.2%.