南宁城市内河水体和表层沉积物中多环芳烃分布特征

采用改进的固相萃取、加速溶剂萃取和高效液相色谱对南宁7条城市内河的水体和表层沉积物样品中6种多环芳烃的残留状况进行了分析测定。检测结果表明,水体中多环芳烃以荧蒽为主,6种多环芳烃在水体中的总残留浓度为26.8～163 ng/L,内河水体各点位苯并[α]芘均超过我国地表水环境质量标准限值,对干流水质存在一定影响。7个点位沉积物中多环芳烃总含量为118.06～416.73μg/kg,6种多环芳烃均有检出。     

HPLC-ICP/MS联用测定废水中甲基汞和无机汞

采用高效液相色谱(HPLC)-电感耦合等离子体质谱(ICP/MS)联用测定废水中可滤态的甲基汞和无机汞,优化了仪器工作条件,讨论了方法干扰及校正办法。甲基汞和无机汞在0.500μg/L~25.0μg/L范围内线性良好,检出限分别为0.03μg/L和0.07μg/L,废水样品平行测定的RSD分别为6.5%~7.6%和6.2%~6.8%,加标回收率分别为84.0%~87.0%和88.0%~92.4%。     

利用PS铝基材版酸洗碱洗处理废液制备拟薄水铝石

以乐凯集团第二胶片厂的PS版酸碱废液为原料,制备出拟薄水铝石。研究了合成拟薄水铝石的中和条件、老化条件、分离与洗涤效果和排放废水情况。实验表明,在pH8.8、温度55℃、强力搅拌下老化24 h,可得晶态纯、不含三水氧化铝杂相、比表面积362.6 m2/g和孔容0.813 mL/g的拟薄水铝石产品,废水符合国家二类排放标准。     

Sorption and desorption of sulfentrazone in Brazilian soils

This study was undertaken to obtain information about the behavior of sulfentrazone in soil by evaluating the sorption and desorption of the herbicide in different Brazilian soils. Batch equilibrium method was used and the samples were analyzed by high performance liquid chromatography. Based on the results obtained from the values of Freundlich constants (Kf), we determined the order of sorption (Haplic Planosol < Red-Yellow Latosol < Red Argisol < Humic Cambisol < Regolitic Neosol) and desorption (Regolitic Neosol < Red Argisol < Humic Cambisol < Haplic Planosol < Red-Yellow Latosol) of sulfentrazone in the soils. The process of pesticide sorption in soils was dependent on the levels of organic matter and clay, while desorption was influenced by the organic matter content and soil pH. Thus, the use of sulfentrazone in soils with low clay content and organic matter (low sorption) increases the probability of contaminating future crops.     

Multiresidue analysis of organophosphate and pyrethroid pesticides in duplicate-diet solid food by pressurized liquid extraction

An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73–117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified ¹⁵N-¹³C-labeled CPF was stable over 16 mo storage at ?20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies.     

A novel dismantling process of waste printed circuit boards using water-soluble ionic liquid

Recycling processes for waste printed circuit boards (WPCBs) have been well established in terms of scientific research and field pilots. However, current dismantling procedures for WPCBs have restricted the recycling process, due to their low efficiency and negative impacts on environmental and human health. This work aimed to seek an environmental-friendly dismantling process through heating with water-soluble ionic liquid to separate electronic components and tin solder from two main types of WPCBs—cathode ray tubes and computer mainframes. The work systematically investigates the influence factors, heating mechanism, and optimal parameters for opening solder connections on WPCBs during the dismantling process, and addresses its environmental performance and economic assessment. The results obtained demonstrate that the optimal temperature, retention time, and turbulence resulting from impeller rotation during the dismantling process, were 250 °C, 12 min, and 45 rpm, respectively. Nearly 90% of the electronic components were separated from the WPCBs under the optimal experimental conditions. This novel process offers the possibility of large industrial-scale operations for separating electronic components and recovering tin solder, and for a more efficient and environmentally sound process for WPCBs recycling.     

乙腈盐析萃取HPLC-PDA同时测定水中11种苯胺类化合物

通过对色谱分析和样品萃取条件的选择和优化，建立了同时分析水中11种苯胺类化合物的HPLC方法。样品经乙腈盐析萃取后直接进样分析，采用 ODS色谱柱，以乙腈-水为流动相进行梯度洗脱，用PDA检测。结果表明，11种苯胺类化合物在0.20~100mg/L范围内其浓度和检测信号呈良好的线性关系，方法检出限为0.002~0.007mg/L，地表水和废水样品加标回收率为81.6%~97.4%，相对标准偏差为1.5%~5.5%。     

Solid-phase extraction for multi-residue analysis of pesticides in honey

A fast and simple multi-residue method for the analysis of 15 organophosphorus (OP), 17 organochlorine (OC), 8 pyrethroids (PYR), 12 N-methyl-carbamate (NMC) pesticide residues and bromopropylate in honey is presented. Ready–to–use EXtrelut®NT 20 column, eluted with dichloromethane, was used to extract the pesticide residues from the aqueous-acetone honey sample, obtaining a clean extract directly analyzable. Determination was carried out by gas chromatography (GC) coupled with flame photometric detector (FPD) for OP compounds and by GC coupled with mass spectrometry detector (MSD) for OC and PYR pesticides and bromopropylate. The NMC pesticides were analysed by liquid chromatography-double derivatization coupled with spectrofluorimetric detector (LC/DD/Fl). This method allows the determination of the 53 pesticide residues at low concentrations (0.0005–0.074 mg/kg) and can be used to assess the compliance with the Maximum Residues Levels (MRLs) set by the European Union. The performance of the method was evaluated and specificity, linearity, recovery, repeatability, reproducibility, limit of quantification (LOQ) and limit of detection (LOD) were determined. A good linearity (r²? 0.99) was found in the range 0.0005–0.074 mg/kg for the majority of the compounds studied. Most of the pesticides had recoveries in the range 70–103 % and values of relative standard deviation (RSD) < 20 for repeatability and reproducibility, showing good accuracy and precision of the method. Aldicarb partially degraded in aldicarb sulphoxide during the analytical procedure, giving anomalous values. The LOQ for all pesticides investigated was from 0.0005 to 0.025 mg/kg while the LOD ranged from 0.0002 to 0.008 mg/kg.     

水样中二甲基乙酰胺不同测定方法比较

水样中二甲基乙酰胺的测定方法主要有紫外分光光度法、双波长法、高效液相色谱法及气相色谱法。对前3种方法进行了探讨,结果表明:紫外分光光度法操作简单、使用广泛;双波长法能消除硝酸盐对二甲基乙酰胺测定的干扰;高效液相色谱法可对复杂水样中的二甲基乙酰胺进行测定,但仪器昂贵。3种方法各有特点,要根据具体所测的水样特征和实验条件选择合适的测定方法。     

不同酸对造纸黑液酸析效果的研究

采用酸析法从造纸黑液中分离木质素,同时去除部分COD和色度,从而完成对黑液的初步处理。实验研究了酸析的最佳pH值,并将硫酸、硝酸、盐酸、磷酸、甲酸和草酸作为酸析剂,分析其分别对黑液色度、COD的去除效果及对木质素提取的影响。介绍了通过快速消解分光光度法来测定COD值,和用分光光度法测定色度值,分别建立COD值和色度对吸光度的工作曲线,使测量更加方便高效快捷,其精确度和准确度都能符合分析方法要求。实验结果表明,酸析效果较好的pH取值范围为2～4,考虑用酸的经济性和处理效果,选择pH=3作为最佳酸析条件;经过对酸析过程规律和原因的分析可得,硫酸、硝酸和磷酸对黑液处理效果较为理想,其中硫酸因其经济性被选为最佳,其色度、COD去除率分别为97.9%和66.1%,木质素的析出量为8.65 g/L。