Quantitative Study Of Five Restricted Colorants In Cosmetics

Pigment red4（CI12085）, pigment red49（CI15630）, basic violet2（CI42520）, acid yellow73（CI45350） and solvent orange16（CI45396） are five restricted colorants used in cosmeticsaccording to Hygienic Standard for Cosmetics （2007edition）. The object of this thesis isdeveloping methods to determine these five colorants in cosmetics quantitatively, and themain content is as followed:1.Study on the determination method of pigment red4. The sample was determined byhigh performance liquid chromatography on a C₁₈reversed column using100%acetonitrile asmobile phase at482nm after extracted by trichloromethane or a mixture of50%trichloromethane and50%absolute ethanol. Pigment red4was analyzed qualitatively base onits retention time while the quantitative analysis was carried out by external standard method.The calibration curve showed good linearity between5μg/mL and500μg/mL for pigment red4. The limit of detection（LOD） was0.03μg/mL and the average recoveries of pigment red4spiked in different types of cosmetics ranged from87.93%to103.43%.2.Study on the determination method of pigment red49. After extractec bydimethylformamide, the sample was detected on a reversed C₁₈column using isocratic elutionwith a mobile phase consisted of30%10mmol/l aqueous tetramethylammonium hydroxide（pH7, adjusted by acetic acid） and70%methanol at494nm. Pigment red49was analyzedqualitatively base on its retention time while the quantitative analysis was carried out byexternal standard method. The calibration curve showed good linearity between1μg/mL and600μg/mL for pigment red49.The LOD was0.2μg/mL,and the average recoveries of pigmentred49spiked in different types of cosmetics ranged from90.94%to101.05%.3. Study on the determination method of basic violet2. After extracted by absoluteethanol, the sample was detected on a reversed C₁₈column using isocratic elution with amobile phase composed of40%0.07mol/Laqueous ammonium acetate and60%acetonitrileat550nm. Basic violet2was analyzed qualitatively base on its retention time while thequantitative analysis was carried out by external standard method. The calibration curveshowed good linearity between0.05μg/mL and3μg/mL for basic violet2. The LOD was5ng/mL, and the average recoveries of basic violet2spiked in different cosmetics rangedfrom90.09%to99.94%. 4.Study on the determination method of acid yellow73and solvent orange16. Afterextracted by methanol, the sample was detected on a reversed C₁₈column usingisocratic elution with a mobile phase consisted of65%0.1mol/L aqueous ammoniumacetate,17.5%methanol and17.5%acetonitrile at492nm. Acid yellow73and solvent orange16were analyzed qualitatively based on their retention time while the quantitative analysiswas carried out by external standard method. The calibration curve showed good linearitybetween5μg/ml and500μg/mL for acid yellow73and solvent orange16respectively. TheLODs were both0.5μg/mL, and the average recoveries of analyte spiked in cosmetics rangedfrom91.24%to106.19%for acid yellow73and from93.22%to101.52%for solvent orange16.The determination methods of five restricted colorants established in this paper wasaccurate and easy to execute, they are suitable for supervision the quality of cosmetics.