Studies On The Analysis Method And Application Of Dechloranes And Hexabromocyclododecane Diastereomers In Sediment And Soils

Dechloranes are a series of chlorinated flame retardants, including Dechlorane Plus (DP), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), Dechlorane 604 (Dec 604) and Mirex. Flame retardants have been rountinely used in textile and polymeric materials to enhance the flame retardancy of consumer products. Because of the large production and consumption, environmental issues have emerged. Many countries had been established the rules to control the use of dechloranes. In this research, dechloranes in sediment were extracted and purified by selective pressurized liquid extraction (SPLE) method. Chromatographic separation, detection and quantification was achieved by gas chromatography-negative ion chemical ionization mass spectrometry (GC-NCI-MS).In this paper, pressurized liquid extraction was selected as extraction method, the sorbent and the sample were added to the extraction cell together for obtain the highest selectivity PLE extraction. As a novel and low-cost sorbent, Mg-Al-layered double oxides (Mg-Al-LDO) was selected as the SPLE sorbent. PLE Parameters affecting the extraction efficiency, including extraction temperature, the type of extraction solvent, static extraction time and cycles were optimized in detail. At the same time, in order to obtain satisfactory purification effect, type and dosage of sorbents were also investigated in this study. The conditions of SPLE as follows:extraction temperature was set at 100 ℃ heating for 5 min. Static extraction period was 10min for three static cycles. The pressure of extraction process was 1500 psi. The sample was washed with 80% of cell volume solvent and purged with pressurized nitrogen gas for 100s.3 g Mg-Al-LDO was chosen as the suitable dosage in the experiment to obtain satisfactory recovery and purification.Under optimal conditions, the recoveries of the dechloranes with three spiked concentration levels (10,100, and 500 ng g-1) were in the range 90.3%-99.8% with the relative standard deviation less than 5.7%. The method showed excellent linearity over the range assayed (1-500 ng g-1) with correlation coefficients (r2) of 0.9992-0.9999. Meanwhile the limits of detections ranged from 0.01 to 0.67 ng g-1 and the limits of quantifications were ranging from 0.03 to 2.22 ng g-1.The analytical method developed was successfully applied for the determination of dechloranes in sediment samples collected in Shandong province. The results indicated that SPLE with as Mg-Al-LDO clean-up sorbent is a fast and reliable extraction technique offering many advantages compared to traditional techniques.In addition, the paper also carried out the analysis and detection of Hexabromocyclododecane (HBCD) in sediments. Sediment was extraction by accelerated solvent extraction, the extract through gel permeation chromatography (GPC) purification and then by solid phase extraction (SPE) to further purify. The collection time for GPC and elution volume for SPE were optimized thoroughly to achieve the highest recovery. The method of separation and determination of three kinds of HBCD isomers was established by LC-MS/MS. The linearity of the calibration curves were in the range 5-1000 ng/g with correlation coefficients (R2) 0.9956-0.9997 for the target HBCD isomers. The limits of detections (LODs) ranged from 0.58 to 0.72 ng·g-1, and the limits of quantifications (LOQs) were ranging from 1.93 to 2.41 ng·g-1. The recoveries using this method at three spiked concentration levels (10,100, 1000 ng·g-1) range from 85.6% to 109% with the relative standard deviation less than 6.5%. The established pretreatment and determination methods with LC-HESI-MS/MS have been used to detect the condition of HBCD isomers in the sediments sampled near a factory. The results indicated that this method is applicable and reliable.