Research On Methods For Determination Of Fluorescent Whitening Agents Vbl And β-carotene

The versatility of high pressure liquid chromatography (HPLC) has made it a standard installation in most chemical and life science industries such as environmental,proteomics,food safety,pharmaceutical development and manufacturing. This paper developments two HPLC methods for determination of fluorescent whitening agents(FWA) VBL in food paper packages and raw pigment β-carotene in vegetables.Paper packages are more widely used in food packaging after June1,2008, when shops and supermarkets are forbidden from offering free plastic bags to customers. But there are many potential contaminants in paper packages including trace elements, fluorescent whitening agents and dyes, sizing agents, organochlorine substances, plasticizers, aromatic hydrocarbons, volatile organic compounds, curing and grease-proofing agents, amines, biocides and surfactants. Fluorescent whitening agents are forbidden to add to food paper packages. The national standard test methods of FWA is as follow:the sample is standard of which the fluorescent area is smaller than5cm2when it exposes to254nm and365nm UV light. A rapid and efficient method for determination of FWA is very important to the study on the safety research and migration test of FWA.VBL is the most widely used fluorescent whitening agents, this paper developments an HPLC method for determination of VBL in food paper packages. The extraction process is as follow:solvent is methanol-water(1:1), extraction time is6h, extraction temperature is75℃, solvent: samples(V/W) is60. Then the extraction using kromasil C18column (4.6mmx300mm,5μm), gradient conditions were as follows:60%solvent B (buffer)20min gradient switched to30%, then held for5min, and then monitored by UV detecter at448nm. The results showed a short run times(18.60min), a good linear relationship and the concentration of P-carotene (R2=0.9996), and the average recoveries was98.72%(n=5). This method is convenient, accurate, precise and sensitive for determination of VBL in food paper packages.Nowadays the major interest of β-carotene, which are widely found in daily diet, is not only due to its provitamin A activity but also to its physiological activities such as reducing risk of some diseases, as cancer, atherogenesis, bone calcification, eye degeneration and neuronal damages. β-carotene analysis in food products may be carried out by different methods:HPLC, spectrophotometry, or color evaluation. While HPLC method is used most widely, it must be operated in a short time due to the active property of β-carotene.This paper developments a rapid HPLC method for determination of β-carotene. The extraction process is as follow:solvent is methanol-tetrahydrofuran(THF)-butylated hydroxytoluene(BHT)(9:1:0.1, V/V), extraction time is30min, solvent:samples(V/W) is10. Then the extraction using kromasil C18column (4.6mm×300mm,5μm), methanol-THF-BHT (9:1:0.01, V/V) as mobile phase, and then monitored by UV detecter at448nm. The results showed a short run times(21min), a good linear relationship and the concentration of β-carotene (R2=0.9997), and the average recoveries was97.84%(n=5). This method has the benefits of accuracy, convenience, adequate reproducibility as well as prevention the β-carotene from oxidating effectively and is suitable for the determination of β-carotene in fresh vegetable samples.