称取防晒化妆品样品5.0 g，加入饱和氯化钠溶液1 mL，充分混匀后用二氯甲烷为溶剂先后2次萃取样品中12种紫外线吸收剂（UVA）。每次萃取用二氯甲烷5 mL，涡旋振荡60 s，超声萃取30 min，并高速离心5 min。收集并合并2次萃取的上清液，吹氮蒸发至近干，用二氯甲烷溶解残渣并定容至1.0 mL。采用DB-5MS色谱柱为分离柱，进样量为1 μL，在80~300℃区间采用程序升温模式可在30 min内对所测12种UVA实现分离；在电子轰击离子源和选择反应监测模式条件下进行串联质谱测定。测得12种UVA的线性范围均在0.01~1.0 mg·L^-1之间，检出限（3S/N）在1.0~3.0 μg·kg^-1之间。在不含目标物的空白防晒化妆品中加入12种UVA的混合标准溶液后，按方法分析求得其回收率及测定值的相对标准偏差（n=6），测得两者的结果依次在93.0%~100%之间和1.2%~4.1%之间。

A portion (5.0 g) of the sunscreening cosmetic sample was mixed thoroughly with 1 mL of saturated NaCl solution and extracted twice with CH₂Cl₂ (5 mL for each extraction) to transfer 12 UV absorbers (UVA) into the organic solvent by swirling for 60 s, extracting ultrasonically for 30 min and centrifuging for 5 min with high speed. The supernatants from the 2 extractions were combined and evaporated to near dryness by N₂-blowing. The residue was dissolved and made its total volume to 1.0 mL with CH₂Cl₂. An aliquot of 1 μL of the CH₂Cl₂ solution was introduced to the chromatographic column of DB-5MS for separation of the 12 UVA under the mode of programed temperature elevation in the temperature interval from 80℃ to 300℃. A clear-cut separation of the 12 UVA was fulfilled within 30 min and their determination was carried out by MS/MS under the modes of EI-ionization source and selected reaction monitoring. Linearity ranges for the 12 UVAs were found same between 0.01-1.0 mg·L^-1. Values of their detection limits (3S/N) found were in the range of 1.0 to 3.0 μg·kg^-1. Test for recovery and precision was performed by addition of mixed standard solution of the 12 UVA to a blank sunscreening cosmetic sample, giving results of recovery in the range from 93.0% to 100%, and results of RSDs (n=6) in the range from 1.2% to 4.1%.