【摘要】 使用透析袋将溶解后的奶粉透析,用乙醚萃取,过C18柱分离后使用4.5 mmol.L-1Na2CO3--4.5 mmol.L-1NaHCO3作为淋洗液,用离子色谱法同时分离和测定了奶粉中亚硝酸根、硝酸根、氯离子和磷酸根。动态透析平衡时间只要1 h左右,四离子的离子色谱峰形较好,共存离子的干扰较小。峰面积与Cl-,PO43-,NO3-及NO2-4种阴离子浓度之间呈线性关系的相关系数依次为0.9982,0.9999,0.9997及0.9867,检出限(S/N=3)依次为9.36,15.0,0.1及0.02 mg.kg-1,测得4种离子测定结果的RSD值(n=7)分别为1.3%,2.6%,2.2%及7.3%。以3种奶粉为基体作加标回收试验,所得回收率均在92%以上。更多还原

【Abstract】 The milk powder sample,after dissolution in water was dialyzed dynamically for 1 h.The dialyzate obtained was extracted with ethylether to remove fatty subsances and separated on C18 column to separate partially those non-polar organic compounds.Eluate from C18 column was filtered with filter membrane of 0.45 μm,and the filtrate was ready for IC determination.Ionpac AS9-HC was used as the chromatographic column and a mixed solution of 4.5 mmol·L-1 Na2CO3 and 4.5 mmol·L-1 NaHCO3 was used as the mobile phase.Determination of the 4 anions was carried out by using conductivity detection.Linear relationships between peak area and concentration of the anions were obtained with correlation coefficients of 0.998 2(for Cl-),0.999 9(for PO3-4),0.999 7(for NO-3) and 0.986 7(for NO-2),and detection limits(S/N=3,mg·kg-1) of 9.36(Cl-),15.0 (PO3-4),0.1(NO-3) and 0.02(NO-2).Values of RSD′s(n=7) found for Cl-,PO3-4,NO-3 and NO-2 were 1.3%,2.6%,2.2% and 7.3% respectively.Tests for recovery were made on 3 kinds of milk powder,giving values over 92%.更多还原