| Sudan red,an unnatural pigment,is a kind of dyes to be used in chemical industry, and belongs to azo dyes.Sudan dyes are widely used in colouring agents such as waxes,floor and shoe polishes.It is an azo dye that is considered to be a genotoxic carcinogen.For instance,Sudanâ… has been tested in mice by bladder implication, resulting in a high incidence of bladder carcinomas and is classified as category 3 carcinogen by the International Agency for Research on Cancer(IARC).From 1995, at any level,in food products destined for human consumption was not allowed in China,the European Union and many other countries.The thief ways to test Sudan red are:,HPLC,LC-MS and GC-MS.All the above ways need great-type apparatus and great expens.In addition,the wide varieties of foods make the experiment conditions more harshly.So,it has very important realistic significance to build a simple method for the determination of Sudan dyes and apply to practice.The thesis includes three parts:In chapterâ… :A sensitive differential pulse polarography method for determination of Sudan I in red chili powder.In Na2HPO4-KH2PO4 buffer(pH 8.0)-5.0×10-4 mol·L-1 K2S2O8 supporting electrolyte.The reduction wave of Sudanâ… at -0.590 V(Vs,SCE) was catalyzed by K2S2O8.A second order derivative peak current is proportional to Sudanâ… concentration in the range of 0.01～0.10 mg·L-1(r=0.999 3),the detection limit is 2.0×10-3 mg·L-1.The sensitivity of the catalytic wave was 5 times higher than that of the corresponding reduction wave.The differential pulse polarography method was applied to determine Sudanâ… in the red chili powder.In chapterâ…¡:A cloud point extraction and HPLC-UV method for determination of Sudan dyes in red chilli powder.Cloud-point extraction(CPE) offers a series of advantages over the traditional extraction methodologies.It allows the extraction and preconcentration of the analytes in single step and is less toxic and cheaper than the conventional extraction procedures.The extract is compatible with the mobile phase used in HPLC.A non-ionic surfactant Triton X-100 as a solvent for the extraction of Sudan(â… ,â…¡,â…¢,â…£) from chilli powder was studied for the first time.The parameters and variables that affect the extraction were investigated.Under optimum conditions:3%of Triton X-100(W/V),10%of Na2CO3(W/V),heat-assisted at 70℃for 30 min,the extraction recovery reached the highest value.A CPE-HPLC(UV) method was developed for the determination of Sudan(â… ,â…¡,â…¢,â…£) dyes in chilli powder. Recoveries of the Sudan dyes ranged between 82.1 to 87.4%in chilli powder by HPLC-UV,with all the relative standard deviations of less than 3%.Limit of detection(LOD) and limit of quantification(LOQ) were in the range of 2.0～4.0 and 7.0～12.0μg·kg-1 in chilli powder,respectively.
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