| Food is a fundation that mankind rely on it for existence development, and the problems of food sceurity have become a focus that attracts the whole world attention. Industy dyes were forbidden using in food processing. Howereve, some food corporation adopt wrongful competition to bring on abusing edible synthesized coloring matter. At present, people pay attention to this problem on food safety.Rhodamine is a basic xanthene dyes, including Rhodamine 110, Rhodamine 123, Rhodamine B, Rhodamine 6G, Rhodamine 101, Rhodamine B ethyl-ester and Rhodamine B n-buthyl-ester and so on. The rhodamine dyes used mainly for acrylic, paper, paint, stain and biotechnology fields such as fluorescent markers. According to the International Agency for Research on Cancer (IARC) of carcinogenic risk assessment of chemicals show that:uptake inhalation and skin contact with the substance will cause harm to acute and chronic poisoning. There is animal experimental data show that the substance has carcinogenic effects when inhaled, may cause mutagenic or teratogenic.China's national standard GB2760-2007, the rhodamine is not incorporated into the basic range of food additives. However, as the alkaline water-soluble than other dyes such as allura red, erythrosine, lemon yellow, sunset yellow and so more easily in preserved fruit, grilled shrimp, candied fruit, chilli products, dyeing and bleaehing is not easy, and low cost, some unscrupulous traders of products with basic rhodamine such as dyeing products to counterfeit the true, the damage to deceive consumers, harm the health of consumers. But there isn't a safe limit for them in our country, and detection institutions can't study every one of the hundreds dyes when they ususlly analyse foods, then forming a shortcomingt.This thesis studies the methods of determination for 7 rhodamine dyes in food by HPLC and LC-MS/MS. This thesis focused on those researches:1. A suitable pre-treatment method was established in different matrix process:the samples were extracted with hexane or methanol-water (1:1, v/v) and then cleaned up by Alumina N SPE/Strata-X-CW solid phase extration carridge; Eluted by methanol conaining formic acid or ammonia water, concentrated and dried in vacuum, solved with methanol, filtrated by 0.45μm micropore filter.2. The conditions of HPLC-MS/MS were developed for determintion of 7 rhodamine dyes in food. The target analytes separaed on SB-C18 column with gradient elution using acetonitrile-water containing 0.1% formic acid as mobile phase. The identification and quantification were achieved by using ESI-MS/MS in positive ion mode and with multiple reaction monitoring (MRM). The linear ranges were from 0.0005 to 1.0 mg/L with the correlation coefficients (r2) above 0.997 for all the 7 rhodamine dyes.3. The established pretreatment and analysis method were applied suceessfully to 187 differen forms of food, and the rate of determination of Rhodamine B was 21.5%. Through the qualitative and quantitativ analysis of the samples, the pretreatment and analysis method established in this paper in point in the 7 rhodamine dyes in various kinds of food and also has highly reliability. |
