| Dimethylsiloxane is a new type of hydrophobic organic pollutants in the environment,which has attracted wide attention due to its persistence,long-distance transport ability,endocrine interference effect and food chain amplification effect.The indoor dust may contain dimethylsiloxane since the special physical and chemical properties of dimethylsiloxane and its wide application in the environment.Therefore,it’s a great significance to study the pollution characteristics of dimethylsiloxane in indoor dust.Organic UV Filters can absorb UVA（Ultraviolet rays A,wavelength 320-400 nm,long wave）and UVB（Ultraviolet rays B,wavelength 280-320 nm,medium wave）in sunlight,organic UV filters can block the two kinds of ultraviolet rays effectively,so it is used in sunscreen and cosmetics.In addition,organic UV filters is also used in plastic packaging boxes,clothing textiles to block the UV radiation.Research shows that organic UV filters have potential physiological harm and toxicity to organisms.In recent years,extensive pollution has been found in river sediment,water,soil,organism and human body with the increase of the production and use of organic UV Filters.The detection method still needs to be improved,it needs to be studied whether organic UV barrier exists widely in domestic environmental media.In this study,two new types of organic pollutants,dimethylsiloxane and UV Filters were selected as the research objects.The analytical method of the target compounds in complex environmental matrix was established and optimized,and the representative samples collected in the typical pollution areas were analyzed.Firstly,a method for the determination of dimethylsiloxane in indoor dust was established in this study.The instrument detection limit of the cyclic dimethylsiloxane D3-D6 was 2.02-2.1 ng/m L,and the chain dimethylsiloxane L3-L16 was 0.68-1.67ng/m L;The instrument quantitative limit of the cyclic dimethylsiloxane D3-D6 is 3.05-3.15 ng/m L,and the chain dimethylsiloxane L3-L16 is 1.02-2.28 ng/m L.The linear range of D3-D6 and L3-L5 is 2.5-500μg/L,the linear range of L6-L16 is expressed as100-10000 g/L by PDMS 200?;The recoveries of cyclic dimethylsiloxane D3-D6 and chain dimethylsiloxane L3-L16 are 57.7±0.6-93.4±12.7%and 78.1±5.7-95.1±8.8%,respectively.We collected the indoor dust samples of 160 cities in China,then analyzed and determined the content of dimethylsiloxane,and revealed the existence and spatial distribution characteristics of dimethylsiloxane in the indoor dust.The detection rates of liner dimethylsiloxane and cyclic dimethylsiloxane in the indoor dust collected in China are 7%-100%,99%-100%respectively.The total content of 18dimethylsiloxanes was 306.24 ng/g dw-102310.80 ng/g dw,and the average value was5612.033 ng/g dw.The pollution levels of 4 cyclic dimethylsiloxanes and 14 liner dimethylsiloxanes were 40.41 ng/g dw-126.67 ng/g dw and 0.56 ng/g dw-661.57 ng/g dw,respectively.It has a higher pollution level compared with other indoor dust levels at home and abroad.Secondly,the method of ultra-high performance liquid chromatography tandem mass spectrometry（UPLC-MS/MS）was established to determine the13 organic UV filters accurately,rapidly and sensitively,and the content of 13 organic UV filters in 5types of samples(river sediment,water,PM2.5 membrane,road dust and sediment core)was tested.The Xevo TQ-S micro mass spectrometry was used in this study,which has a stepwave ion transport channel to minimize ion loss and remove neutral substances.Electrospray ion source mode（ESI）was chosen as the positive ion mode,mass spectrometry was carried out under the dynamic MRM and trigger MRM acquisition modes,which improved the sensitivity and reduced the detection limit of the instrument greatly.The detection limit S/N=5)and quantitative limit（S/N=10）of 13 organic UV filters were 0.001-0.025μg/L and 0.002-0.05μg/L respectively.The correlation coefficient R2>0.9975 in the liner range.The relative standard deviation（RSD）was within 5%,and the reproducibility of the method was good.The results of the sample analysis showed that 13 organic UV filters existed in the samples,which indicated that organic UV filters existed in the environment widely. |
