离子色谱法测定肥料中三聚氰胺的含量

Determination of Melamine in Fertilizer by IC

采用离子色谱分析法检测肥料中三聚氰胺的含量。样品用氨水-甲醇-水(2+7+1)溶液超声振荡提取,离心后经氮气吹干,用3 mmol·L^(-1)甲烷磺酸溶液定容,分离柱和保护柱均为Dionex IonPac R SCS1,淋洗液为含3mmol·L^(-1)甲烷磺酸的乙腈-水(15+85)。采用非抑制型电导检测器检测。三聚氰胺的线性范围为1.00~1 000mg·L^(-1),检出限(3S/N)为5mg·kg^(-1),测定下限(9S/N)为15mg·kg^(-1)。加标回收率在79.3%~116%之间,测定值的相对标准偏差(n=6)在3.4%~13%之间。

IC was applied to the determination of melamine in fertilizer.The sample was extracted ultrasonically with a mixture of NH_3 · H_2O＋CH_3OH＋ H_2O（2＋7＋1）.After centrifuging,the extract was evaporated to dryness by N_2-blowing,and the residue was dissolved with 3mmol·L^（-1） methylsulfonic acid solution.Dionex IonPac R SCS1 columns were used both as separation and guard columns and a mixture of acetonitrile and3mmol·L^（-1） methylsulphonic acid solution（15＋85）was used as eluent. Melamine was detected by nonsuppressed conductivity detector.The linearity range of melamine was between 1.00-1 000 mg·L^（-1）.The detection limit was 5 mg·kg^（-1） and the limit of quantification was 15 mg·kg^（-1）.Values of recovery found by standard addition method were in the range of 79.3%-116%and RSD′s（n=6）were in the range of 3.4%-13%.