免试剂离子色谱法检测水产品及其制品中的多聚磷酸盐

Determination of Polyphosphates in Aquatic Products and their Products by Free Reagent Ion Chromatography

利用免试剂离子色谱建立了水产品中常见的正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐的检测方法。该方法使用三氯乙酸作为蛋白质沉淀剂和酶失活剂,样品经匀浆,超声萃取,离心,减压过滤,调pH后,再经OnGuardⅡRP柱除去微量的蛋白质和脂肪,从而保持色谱柱的柱效,延长色谱柱的使用寿命。稀释适当的倍数,经0.20μm水系膜过滤器过滤后,进入离子色谱系统,经KOH梯度淋洗,IonPac AG11-HC(4mm×50mm)保护柱,IonPac AS11-HC(4mm×250mm)分离柱分离后,用抑制型电导检测器进行结果检测。此法使4种磷酸盐阴离子在0.1～100mg/L范围内均呈现良好的线性,其相关系数均在0.999以上。虾肉中这4种离子的加标回收率在95%～103%之间,RSD在1%以内,日内精密度和日间精密度均符合要求,结果令人满意。此法方便、快捷、安全、可靠,其使用范围可扩展到水产制品中,是一种应用范围广、检测迅速、检测成本低廉且环境友好的新型检测方法。利用该方法检测了市售冰冻扇贝、冰冻虾仁及虾丸中各磷酸盐的含量,结果发现多聚磷酸盐的添加现象较普遍,以冷冻虾仁中磷酸盐含量严重超标。本研究可为政府监管部门提供基础数据。

In this study,a method to determinate orthophosphate、pyrophosphate、tripolyphosphate and trimetaphosphate simultaneously by free reagent ion chromatography was established,using trichloroacetic acid as a protein precipitating reagent and enzyme inactivation reagent,after homogenization,ultrasonic extraction,centrifugal,vacuum filtration,adjusting the pH of the extraction solution,which could maintain the solution in alkaline zone and the stability of polyphosphates,and then a small quantity of protein and fat were removed by On Guard Ⅱ RP column,thereby keeping the column efficiency and extending the life of ion-exchange column. After an appropriate multiple of dilution,the extraction solution through 0.20 μm membrane filters,the filtrate was injected into the ion chromatography system to determinate： potassium hydroxide solution as the gradient eluent,IonPacAG11-HC（4 mm×50 mm） ,IonPacAS11-HC（4 mm×250 mm） ,suppressed conductivity detector. This method showed a better linear in range of 0.1～100 mg/L,the correlation coefficient was 0.999. Phosphates recoveries in shrimp got up from 95% to 103% and RSD was less than 1%,and the better intra-day precision and day precision,so all of the indexes satisfied the relevant requirements. This method is more convenient,faster,safer,more reliable,and it can be expanded to aquatic products,it is a new detection method with applications widely,detection low-cost and environment friendly. And using this method to detect the phosphate of concentrations of commercial frozen scallops,frozen shelled shrimps and shrimp balls,it was found that the addition of polyphosphates were prevalent,especially the concentration of phosphate was far beyond the limit in frozen shelled shrimp,all of these can apply basic data to our governmental regulation department.