| Recently, azo dyes have been used as colorant in many daily products, such as paint,plastic, food, cosmetic and leather. The speed of production and consumption isincreasing fast. With the rapid development of dyestuff industry, the problem aboutthe abuse and pollution of dye has aroused concern all over the world. EU2002/61Decree specified that azo dyes which released carcinogenic aromatic amines in thereduction condition are banned. However, some banned azo dyes are still used inprinting and cosmetic industries. The azo dyes in industrial wastewater may enter intowater system and contaminate the water. The azo dyes in lipstick can easily pass tohumans and endanger health. In order to ensure people health and slow pollution, it isimportant and necessary to monitor azo dyes in waters and cosmetics.With the unceasing progress of science, the trend of chemical analysis has beenfrom macro-analysis to trace analysis gradually. The way of trace analysis can bemore adaptive to determination of organic compounds and metal residues in kinds ofmatrixes. It has become a common goal for scholars and professionals in manycountries to develop analytical methods which are rapid, accurate, inexpensive andpollution-free. In this paper, methods of extracting azo dyes in waters and lipstickswere studied under the principle of energy saving and environmental protection.1. Development of a vortex-assisted ionic liquid microextraction coupled with ultrafast liquid chromatography for determination of aromatic amines in water samplesIn this section, vortex-assisted ionic liquid microextraction （VAILME） was firstlydeveloped for the rapid and simple extraction of three aromatic amines in watersamples, followed by determination with ultra fast liquid chromatography （UFLC）.The organic dispersive solvent used in the traditional dispersive liquid-liquid microextraction was avoided in the pretreatment process.[C6MIM][PF6] was used asextraction solvent which can disperse in water sample completely and quickly byvortex. Under the optimized conditions, the limits of detection and quantification ofthe analytes are in the range of0.24-0.57μg L-1and0.80-1.90μg L-1, respectively.The intra-day and inter-day precision is in the range of2.3-3.5%and2.8-5.3%,respectively. The proposed method was applied to determination of three aromaticamines in six kinds of water samples and satisfactory recoveries of the analytesranged from79%to111%（the relative standard deviations≤6.0%）. By comparingthe proposed method with other sample preparation methods, the proposed methodshow several advantages, such as low organic solvent consumption, short extractiontime and good repeatability values.2. Determination of Sudan dyes and Pigment red4in lipsticks based on miniaturizedmatrix solid phase dispersion–ultra fast liquid chromatographyIn this study, miniaturized matrix solid phase dispersion （MSPD） was applied tothe extraction of five dyes （Sudan I、II、III and IV and Pigment red4） in lipsticks.Separation and determination of all dyes were performed by ultra fast liquidchromatograph （UFLC） coupled with UV-vis detector. It is somewhat difficult toweigh lipstick samples accurately which are ropy and ceraceous. Watch-glass wasused as sample carrier in the MSPD procedure. The experiment results indicate theproposed method required only small sample amount, low solvent volume and fewsteps. Effects of experimental parameters for MSPD, such as the sorbent, the kind andvolume of the elution solvent and the mass ratio of sorbent to sample were carefullyevaluated. Acetone was used as elution solvent and silica gel was used as sorbent.Linear regression coefficients （r≥0.9992）, precision （RSDs≤8.9%） and detectionlimits (LODs≤6.21μg L-1) were satisfactory. This method was applied to analyzeseveral lipsticks from different manufacturers and the recoveries of the analytes werein the range of67-98%. MSPD-UFLC is a reliable analytical method and can be alsoapplied to determination of red dyes in other cosmetics products, such as eye shadowand blush cosmetics. |
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