气相色谱内标法测定化妆品中的甲醇和乙醇含量

Determination of methanol and ethanol in cosmetics using internal standard by gas chromatograph

建立了气相色谱内标法测定化妆品中甲醇和乙醇的方法。通过考察稀释液、内标物和气相色谱柱等条件,以N,N-二甲基甲酰胺作为稀释液,异丙醇作为内标物,选用DB-FFAP毛细管柱进行色谱分离,保留时间定性,内标法定量,并与《化妆品卫生规范》(2007版)中气相色谱顶空外标法测定甲醇的方法进行了比较。结果表明,用气相色谱内标法测定化妆品中甲醇和乙醇的含量,在0.8 mg/L～500 mg/L范围内具有良好的线性关系(R2甲醇=0.999 8和R2乙醇=0.999 7),相对误差<2.4%,回收率为92.7%～104.7%(n=6)。

Methanol and ethanol in cosmetics were determined using internal standard by gas chromatography. The solvent, GC capillary column and internal standard were studied and discussed. The objectives were separated by DB-FFAP capillary column using N, N-dimethylformamide as solvent, and quantified by isopropanol as internal standard. At the same time, this method was compared with the standard one in Hygienic Standard for Cosmetics, of which GC with headspace automatic sampler was used and external standard was employed as quantitative methods. Results showed that there was a nice linear relationship when the concentration of objectives was in the range of 0.8 mg / L - 500 mg/ L （R2 methanol = 0.999 8; R2 ethanol = 0.999 7 ）. The average recovery ranged from 92.7% to 104.7% （n = 6 ）, with a relative derivation less than 2.4%.