两种凝胶色谱在农药残留分析中的应用比较

介绍了凝胶色谱法的基本原理和工作方式及其在农药残留分析中的应用,对比了传统的全自动凝胶色谱和在线凝胶色谱-质谱联用两种凝胶色谱仪的特点。通过土壤样品有机磷和有机氯农药加标回收试验,表明两种凝胶色谱在农药残留分析中的净化效果差异不大,而在线凝胶色谱-质谱联用在检测快速化、在线化和溶剂使用少量化、微量化方面更具优势。     

Dissipation of difenoconazole in apples used for production of baby food

Dissipation of fungicide difenoconazole (3-chloro-4-[(2RS,4RS;2RS,4SR)-4-methyl-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl]phenyl 4-chlorophenyl ether) was studied following its application on apples intended for production of baby food. The apples (varieties: Jonagold Decosta, Gala and Idared) were sprayed with the formulation to control pathogens causing fungal diseases: powdery mildew (Podosphaera leucotricha ELL et Ev./Salm.) and apple scab (Venturia inaequalis Cooke/Aderh.). A validated gas chromatography-based method with simultaneous electron capture and nitrogen phosphorus detection (GC-ECD/NPD) was used for the residue analysis. The analytical performance of the method was highly satisfactory, with expanded uncertainties ≤ 19% (a coverage factor, k = 2, and a confidence level of 95%). The dissipation of difenoconazole was studied in pseudo-first-order kinetic models (for which the coefficients of determination, R², ranged between 0.880 and 0.977). The half-life of difenoconazole was 12–21 days in experiments conducted on three apple varieties. In these experiments, the initial residue levels declined gradually and reached the level of 0.01 mg kg^?1 in 50–79 days. For the residue levels to remain below 0.01 mg kg^?1 (the maximum acceptable concentration for baby foods), difenoconazole must be applied approximately 3 months before harvest, at a dose of 0.2 L ha^?1 (50 g of an active ingredient per ha).     

长三角地区池塘养殖水产品体内农药类污染与食用风险评价

为了解池塘养殖水产品体内的农药污染情况,以便为水产品质量评价及保障当地居民的饮食健康提供科学依据,本研究采用气相色谱质谱联用法(GC-MS)对长三角地区13个养殖池塘中5类(蟹类、鳖类、蚌类、虾类、鱼类)水产品体内9种有机磷农药(OPPs)、8种有机氯农药(OCPs)以及4种拟除虫菊酯类农药(SPs)进行了检测,并初步分析了其污染来源。结果表明,水产品体内3类农药均有检出,但残留水平均不高,OPPs残留总量为未检出至299 ng·g-1(dw),三唑磷、伏杀硫磷、喹硫磷和毒死蜱较易在水产品体内蓄积;OCPs残留总量为16~82 ng·g-1(dw),主要污染物为六六六(HCHs),主要来自历史残留;SPs残留总量为44~89 ng·g-1(dw),主要污染物为高效氯氟氰菊酯。水产品体内的农药污染可能与养殖池塘中的沉积物污染密切相关。5类水产品体内3类农药的总风险指数(HI)为0.0020~0.046,远小于1,因此,长三角地区由3类农药造成的健康风险处于安全水平。     

Uncertainty of exposure assessment of consumers to pesticide residues derived from food consumed

The sources of quantitative and qualitative uncertainties of the exposure of a consumer to a pesticide residue are identified. The contribution of quantifiable uncertainties of input parameters of deterministic model to the combined uncertainty of the estimated exposure is shown with detailed calculation using the pesticide residue content of food consumed during two days. The daily intakes of bifenthrin residues calculated for the 60 kg bodyweight of the reporting person are 0.00257 mg/kgbw and 0.00281 mg/kgbw for day 1 and day 2, respectively with 27-28% combined uncertainty. The major contributors were fruits and whole meal bread. The contribution of the individual steps to the combined uncertainty depends on the particular food item. In general, the variability of recipes, estimation of the mass of consumed food, sampling, processing of raw commodities and analysis of pesticide residues influenced most, in decreasing order, the combined uncertainty of the estimated daily exposure.     

Field evaluation and determination of four herbicides in a wheat ecosystem by a simple and versatile QuEChERS method with liquid chromatography-tandem mass spectrometry

Wheat products are consumed worldwide and every day; therefore, herbicides misuse in the wheat ecosystem has become a global food safety issue. Here, a simple and versatile method, QuEChERS (quick, easy, cheap, effective, rugged, and safe) with liquid chromatography-tandem mass spectrometry was developed to measure four herbicides in soil, wheat, and wheat straw – florasulam, carfentrazone-ethyl, fluroxypyr-meptyl, and fluroxypyr. By adjusting the amount of graphitized carbon black from 0 to 10 mg, the herbicides could be extracted with satisfactory recoveries of 80%–110%. Application of two water-dispersible granules showed first-order kinetics as well as half-lives between 1.2 and 5.1 d under open-field conditions. The dissipation kinetics of the four herbicides differed in the soil, wheat, and wheat straw, with residual concentrations in straw at 2 h after application being higher than in soil and faster degradation occurring in straw. The terminal residues in soil, wheat grain, and wheat straw were all below the maximum residue limits. The developed method was easy to handle and versatile; thus, it will facilitate regulation and inspection for possible misuse against Good Agriculture Practices. Moreover, the results of this study will contribute to global environmental protection as well as food safety issues.     

制药行业药渣污泥干化工艺研究

通过对南阳市危废处置中心药渣污泥干化系统的研究,设计了一套有效的干化系统,使药渣污泥的含水率从75%～80%干化至含水率20%,为药渣污泥进一步减量化、无害化和资源化处理提供更多的可能。系统配套有效的尾气处理系统,使该项目废气排放指标达到《工业炉窑大气污染物排放标准》(GB9078-96)以及《恶臭污染物排放标准》(GB14554-93)中的相关要求。     

铬渣湿法和干法解毒技术的应用对比

通过对国内典型铬渣处理的项目进行分析,并结合某铬渣污染治理工程实例,从反应机理、解毒工艺、工艺适应性、资源回收利用、设备选型、处理规模、场址选择、污染控制及安全生产和经济性方面对铬渣湿法解毒和干法解毒技术在实际应用中的选择进行对比,为该项目提出了更适合的解毒技术。     

锰磁活性炭的制备及其性能表征

以酶解提制烟碱后的烟渣和电解锰渣回收锰为原料,制备具备磁性和发达孔隙的活性炭。利用氮气吸附技术、红外光谱（FTIR）表征与分析了活性炭表面的孔隙结构和物化性质,考察了活性炭对亚甲基蓝的吸附性能和磁学性能。结果表明：以Mn／C基质废弃物为原料制得活性炭具有磁学性能;适量锰的添加有利于活性炭微孔的形成和发育;采用一步焙烧法有助于磁化物和活性炭基体相互作用形成化学键合,提高饱和磁化强度,实现废弃资源的充分利用。     

氯化锌法改性小麦秸秆制备生物碳质吸附剂及其对磷酸根的吸附效果

为实现农作物秸秆资源化,解决水体富营养化问题,将小麦秸秆化学改性成一种可以有效吸附水体中磷酸根的生物碳质吸附剂,重点考察了氯化锌法改性小麦秸秆制备生物碳质吸附剂的最佳工艺条件以及产品对水体中磷酸根的去除效果。结果表明,当氯化锌溶液质量浓度为250 g/L、浸渍比为2.2∶1、活化温度为600℃、活化时间为45 min时,所得的小麦秸秆生物碳质吸附剂的得率为37.85%,对磷酸根的去除率为99.33%。     

废柴油再生工艺废弃物的固化实验

废弃油基钻井液中废柴油再生工艺产生的废渣废液具有高COD和高色度等特点,直接外排对环境危害严重。通过单因素实验和正交实验确定了该废弃物的最佳固化配方为:水泥∶粉煤灰为3∶2,水泥和粉煤灰加量30%,石膏加量1.5%,硫酸铝加量1.5%,石灰加量1%。在最佳固化配方下,废弃物浸出液的COD由10 062 mg/L降至62 mg/L,色度由500倍降至8倍,各主要污染指标都符合《污水综合排放标准》(GB 8978-1996)一级标准,固化成本约120元/m3。通过固化体的宏观照片和微观SEM照片对固化机理进行了分析,结果表明,废弃物被稳固地包裹在固化体之中。