Study On Proficiency Testing And Method Of Determination Of 3-Chloro-1,2-propanediol In Soy Sauce

In order to understand capability of determination of 3-chloro-1,2-propanediol(3-M CPD)among Chinese testing labs,Certification and Accreditation Administration of the People's Republic of China(CNCA)organized the proficiency testing on determination of 3-MCPD in soy sauce.After statistical and technological analysis for experimental resuLts of labs and thorough comparative study of all present detection methods for 3 -MCPD,the optimal method is determined by optimizing experimental conditions whic h have influence on experimental accuracy according to proficiency testing results.Split-level test samples are used in proficiency testing and prepared by reguLated procedure.The results are evaluated by interquartile range and median robust statistical techniques.Single-factor variance analysis is used in uniformity test and t-test method for assessing the stability of samples.Optimizations are done in column chromatography method, sample derivation method,as well as separation and analysis method of GC-MS.These methods are validated after analysis for experimental resuLts of the proficiency testing.The samples used in proficiency testing are homogeneous and steady.Statistical resuLt indicates that the labs with satisfactory experiment resuLts in this proficiency testing are below 70%.The labs which got the suspicious and unsatisfactory resuLts also approve the evaluation resuLts.The optimal experimental conditions:Samples are eluted from extrelut chromatography column(Extrelut(?)NT);elute:hexane/ether mixture,eluate:ether/methanol mixture;Derivatization with heptafluorobutyrylimidazole(HFBI),Analysis using GC-MS in the selective ion monitoring mode.Internal standards are used for quantification.Most labs in proficiency testing have the ability of determining 3-MCPD,however the existing of so many suspicious or unsatisfactory resuLts indicates that shortcomings in present methods may be the main reason for it;ResuLts show that sample preparation method and statistical evaluation methods for this proficiency testing are all appropriate;Test for actual samples indicates that satisfactory resuLts can be achieved with conditions determined in this paper.