摘要
于在线固相萃取分离-紫外分光光度法测定乳制品中三聚氰胺（ML）含量的FIA系统中，引入了双柱结构（自制的PCX1柱和PCX2柱），并采用异步注射分析模式。调节乳制品样品酸度为pH4．5。样品进入FIA系统后先后经过如下过程：流经PCX柱富集ML；用甲醇-水（75＋25）溶液清洗150S，除去吸附在柱上的其他杂质；用氨水-甲醇-水（1＋25＋74）混合液洗脱ML（洗脱时间PCX1柱为36S，PCX2柱为34s）；洗脱液经采样环（体积60μL）采样，0．3mol·L^-1氯化铵溶液作载流，推动采样环中“样品塞”流至流通池，于237nm处进行光度检测。测得ML的质量浓度在0．50-40．0mg·L^-1内与相应的吸光度呈线性关系，检出限（3s／k）为0．21mg·L^-1。加标回收率在98．1％-108％之间，测定值的相对标准偏差（n=11）依次为4．2%，0．87%。
A dual-column （the self-made PCX column 1 and 2） construction was introduced into the FIA system for UV-spectrophotometric determination of melamine （ML） in dairy products with on-line SPE enrichment, and asynchronous injection mode was adopted in the analysis. The dairy sample was adjusted pH 4. 5 and introduced into the FIA system. In flowing through the PCX column ML was retained on the column by ion-exchange. The column was cleaned up with a washing solution composed of CH3OH and H20 （75＋25） for 150 s to remove adsorbed impurities, before etution of ML from the column with an eluant composed of aq. ammonia-CH3OH-H20 （1＋25＋74）. Time of elution for PCX1 was set at 36 s and for PCX2 at 34 s. The eluate was carried over to the sample loop （voh of this loop 60μL） and its ＂sample plug＂ was carried over by 0. 3 mol·L^-1 NH4C1 solution acting as carrier to the flow-through cell where UV-detection was made at the wavelength of 237 nm. Linear relationship between values of absorbances and mass concentration of ML was obtained in the range of 0. 50- 40. 0 mg·L^-1 with detection limit （3s/k） of 0. 21 mg·L^-1. Values of recovery found by stardard addition method were in the range of 98.1%-108%, and values of RSD＇s （n=11） were 4. 2% and 0. 87%, respectively.
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2016年第12期1419-1423,共5页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
