充氮蒸馏-离子色谱法测定香菇中二氧化硫残留量

Determination of Sulfur Dioxide Residues in Lentinus Edodes by Distillation of Filling Nitrogen and Ion Chromatography

建立了充氮蒸馏-离子色谱法测定香菇中二氧化硫残留量的分析方法。称取3.00 g样品加入蒸馏瓶后加入150 mL蒸馏水和5 mL盐酸,以20 mL过氧化氢溶液为接收液,经充氮蒸馏(功率300 W,氮气流速200 mL/min)8 min后定容并稀释,采用离子色谱法测定,外标法定量。在此试验方法下,二氧化硫在0~5.00 mg/L范围内呈良好线性关系,线性相关系数r^(2)=0.99978;检出限为0.2 mg/kg,定量限为0.6 mg/kg;在高中低3个加标水平下干香菇中二氧化硫平均回收率为74.0.%~84.1%,相对标准偏差(RSD)为0.9%~3.2%;新鲜香菇的平均回收率为76.0%~110.3%,RSD为0.9%~5.1%。在实际样品测定中,55份香菇样品中二氧化硫检出率为100%,范围为5.24~110.97 mg/kg,超标率为56.7%(鲜香菇)和28.0%(干香菇)。结果表明,该方法精密度高、重现性好,可用于香菇中二氧化硫残留量的测定。

The method of filling nitrogen distillation and ion chromatography to determine the sulfur dioxide residues in Lentinus edodes was developed.150 mL distilled water and 5 mL hydrochloric acid were added into distillation flask with 3.00 g samples,and 20 mL hydrogen peroxide solution was used as the receiving solution.After 8 min of filling nitrogen distillation (power 300 W,nitrogen flow rate 200 mL/min),the samples were determined by ion chromatography and quantified by external standard method.The linear correlation coefficient r^(2) was 0.99978,The limit of detection was 0.2 mg/kg and the limit of quantification was 0.6 mg/kg.The average recovery rate of the sulfur dioxide residues in dried Lentinus edodes ranged from 74.0% to 84.1%,relative standard deviations (RSD) ranged from 0.9% to 3.2%;The average recovery rates of fresh Lentinus edodes were 76.0%~110.3%,and RSD were 0.9%~5.1%.The detection rate of sulfur dioxide in 55 batches of Lentinus edodes samples was 100%,ranging from 5.24 mg/kg to 110.97 mg/kg,and the exceeding standard rate was 56.7% (fresh Lentinus edodes) and 28.0% (dried Lentinus edodes).The results showed that the method had high precision and good reproducibility,and could be used for the determination of sulfur dioxide residues in Lentinus edodes.