Determination of 23 Volatile Organic Compounds in Air Freshener by Gas Chromatography-Mass Spectrometry

GC-MS was applied to the determination of 23 volatile organic compounds (VOCs) in air freshener. The pretreated sample (0.500 0 g) was placed in a graduated 10 mL tube and 0.10 mL of mixed internal standard solution was added for quantification. Triacetyl-glyceride was added to make its volume to 10.0 mL. Anhydrous Na₂SO₄ (3 g) was added and the mixture was swirled for dehydration. After standing for 1 h, 1.0 mL of the supernatant was taken and filtered through 0.45 μm filtering membrane. The filtrate was used for analysis by GC-MS according to the working conditions of the instruments. Triacetyl-glyceride was chosen as the solvent in dilution of sample solution and in preparation of standard solutions of VOCs and of internal standards. Two internal standard compounds, i.e., ethoxypropanediol and bromobenzene were added in the mixed standard solution, with their concentrations same as 200 mg·L^-1. In the determination of 3 etheric compounds among the 23 VOCs, ethoxypropanediol was used as internal standard, and in the determination of the remainder compounds, bromobenzene was used as internal standard. The DB-FFAP polar column was satisfactorily effective for separation of both the 23 VOCs and the 2 internal standards, But due to interferences caused by high contents of ethanol and water in the sample, benzene, toluene, α-pinene, ethylbutyrate and butylacetate were separated on the non-polar DB-1 column. Linearity ranges of the 23 VOCs were found same between 0.50 to 10.00 mg·L^-1, and the detection limits (3S/N) were found all less than 10 mg·kg^-1. Recovery was tested by standard addition method at 4 concentration levels of 10, 20, 100, 200 mg·kg^-1, giving results in the range of 88.3%-113%. Values of RSDs (n=6) were found all lower than 5.0% with an exception of 6.5% for acetone at the concentration level of 10 mg·kg^-1.