气相色谱法同时测定水中多种有机氯农药和多氯联苯

建立了一种同时测定水中16种有机氯农药(OCPs)和8种多氯联苯(PCBs)的气相色谱/电子捕获分析方法。样品经正己烷液液萃取、氮吹浓缩后,以自动不分流进样方式用气相色谱/电子捕获器检测,并对色谱条件进行优化,采用外标法定量。在较佳的试验条件下,16种OCPs和8种PCBs标准曲线的线性相关系数为0.999 0～0.999 9,方法检出限为0.001～0.002μg/L,OCPs和PCBs的平均加标回收率分别在(88.1%～107.0%)、(91.8%～104.2%)之间,相对标准偏差(RSD,n=5)分别为(2.87%～10.42%)、(3.96%～9.02%)。该方法灵敏、准确、稳定,分析时间短,适用于大批量水样中痕量有机氯农药和多氯联苯的测定。     

Gender difference in walleye PCB concentrations persists following remedial dredging

Eleven male walleyes (Sander vitreus) and 10 female walleyes from the Saginaw Bay (Lake Huron) population were caught during the spawning run at Dow Dam (Midland, Michigan) in the Tittabawassee River during April 1996, and individual whole-fish polychlorinated biphenyl (PCB) determinations were made. Total PCB concentrations averaged 7.95 and 3.17 mg/kg for males and females, respectively. As part of the Natural Resource Damage Assessment remediation process, contaminated sediments from the Saginaw River, the main tributary to Saginaw Bay, were removed during 2000 and 2001. Total PCB concentrations of 10 male and 10 female walleyes caught at Dow Dam during April 2007 averaged 1.58 and 0.55 mg/kg, respectively. Thus, dredging of the Saginaw River appeared to be effective in reducing PCB concentrations of Saginaw Bay adult walleyes, as both males and females decreased in PCB concentration by more than 80% between 1996 and 2007. However, the ratio of male PCB concentration to female PCB concentration did not decline between 1996 and 2007. This persistent gender difference in PCB concentrations was apparently due to a gender difference in habitat utilization coupled with a persistent spatial gradient in prey fish PCB concentrations from the Saginaw River to Lake Huron.     

Risk-benefit modeling to guide health research in collaboration with Great Lakes fish consuming Native American communities

It is well documented that fish consumption imparts both health risks and benefits. Furthermore, fish harvest and consumption are an essential part of Great Lakes Native American cultures. Quantitative models that compare risk and benefits to potential consumption scenarios can help guide future health research as well as consumption advice for potentially sensitive populations. This article presents fish consumption scenarios based on self-reported meal plans constructed by tribal members in eastern upper peninsula and northern lower Michigan Anishinaabe. Two risk–benefit models were applied to these scenarios to estimate the potential neurodevelopmental and cardiovascular risks (either increased or reduced risk) from dioxin-like polychlorinated biphenyls (DL-PCBs), methylmercury (MeHg), and omega-3 polyunsaturated fatty acids (n3-PUFA). All scenarios except maximum exposure estimates (i.e. 25th–75th percentile MeHg, DL-PCB, and n3-PUFA intakes) predicted reduced cardiovascular risk and improved neurodevelopmental outcomes. The greatest predicted benefits (adjusted for risks) occurred at the 75th percentile intake of MeHg, DL-PCB, and n3-PUFA scenarios: 5.0 visual recall memory (VRM) and 4.41 Intelligence Quotient (IQ) benefits, and 28% reduced risk of cardio-vascular disease. Scenarios based on maximum self-reported intake, however, predicted health detriments. These results suggest that most fish consumption scenarios as constructed in collaboration with Native American communities could impart health benefits despite the presence of contaminants. However, high-end consumption estimates warrant caution as well as the need for well-crafted advice. Potential benefits further underscore the value of reducing contamination burdens in Great Lakes fisheries. Future priorities of ongoing contamination monitoring and health research are discussed.     

Spatial Distributions and Temporal Trends in Sediment Contamination in Lake St. Clair

The sediments of Lake St. Clair were surveyed in 2001 for a range of compound classes including metals (such as total mercury and lead), polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, organochlorine pesticides, polycyclic aromatic hydrocarbons, and short- and medium- chain chlorinated paraffins, in order to evaluate the spatial distribution and temporal trends of contamination. Concentrations of contaminants were generally low compared to the lower Great Lakes (Erie and Ontario), and were typically below the Canadian Sediment Quality Probable Effect Level (PEL) guidelines. The only exceptions were for mercury and DDE, where concentrations exceeded their respective PEL at one of the thirty-four sites sampled. With the exception of mercury, it was difficult to interpret spatial trends in contaminant concentrations due to these low levels, although relatively elevated concentrations of several contaminants were found in L’Anse Creuse Bay and at the outflow of the Thames River. In the case of mercury, historically-contaminated sediments in the St. Clair River associated with chlor-alkali production appeared to contribute to loadings to Lake St. Clair. There have been substantial reductions in sediment contamination in Lake St. Clair over the past three decades, as determined through sediment core profiles as well as through comparison of current data to those from historical surveys conducted in the early 1970s. These results indicate that management actions to reduce contaminant loadings to Lake St. Clair have been generally successful.     

磁固相萃取—热脱附—气相色谱—串联质谱检测水中7种多氯联苯

利用氧化石墨烯—四氧化三铁(Fe₃O₄@GO)磁性吸附剂进行磁固相萃取(MSPE),结合在线热脱附—气相色谱—三重四极杆串联质谱系统(TD-GC-MS/MS)建立了一种免有机溶剂的定量检测水中7种指示性多氯联苯(PCBs)的方法。优化了Fe₃O₄@GO的用量、萃取时间及溶液pH等影响磁固相萃取效率的关键因素。在最优条件下,7种PCBs在2～100ng/L内呈良好线性关系,线性相关系数(r)>0.98。检测限(S/N=3)和定量限(S/N=10)分别为0.18～0.40,0.57～1.32ng/L。平均回收率为85.9%～106.2%,相对标准偏差(RSD)为4.0%～13.1%。该方法可用于水样中痕量PCBs污染的快速监测。     

Experimental study on low temperature thermal treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) in fly ash

The effects of temperature and time on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) distribution in fly ash of a municipal solid waste incinerator (MSWI) were studied in a tubular oven under nitrogen atmosphere. The PCDD/Fs in the gas phase and solid phase were detected by high-resolution gas chromatography coupled with low resolution mass spectrometry (HRGC/LRMS) separately. The experimental results showed that the major congener was octa-chlorinated dibenzo-p-dioxin (OCDD) in the gas phase and the low chlorinated congeners were the major products in the solid phase. There were high levels of OCDD in the gas phase in several experimental conditions although the PCDD/Fs in the solid phase could be decomposed. The optimum condition for PCDD/Fs decomposition in fly ash was a heating time of 60 min at 400 °C under nitrogen atmosphere. Translated from Proceedings of the CSEE, 2005, 25(23): 95–99 [译自:中国电机工程学报]     

气相色谱-质谱法测定土壤中8种多氯联苯

土壤中多氯联苯经索氏提取后用浓硫酸净化,由气相色谱-质谱法测定,方法回收率为89.2%～109.5%,相对标准偏差为2.5%～11.9%。实验结果表明,本方法适用于土壤样品中多氯联苯的测定。     

双重净化-气相色谱法同时测定蛋及蛋制品中六六六、滴滴涕和指示性多氯联苯

建立同时测定蛋及蛋制品中六六六、滴滴涕和指示性多氯联苯残留量的双重净化-气相色谱法。样品经乙腈提取,浓硫酸和焙烧型水滑石双重净化后采用气相色谱分析和外标法定量。结果表明：与传统的磺化法相比,采用浓硫酸和焙烧型水滑石双重净化的效果更好,干扰物质少,且目标物提取更充分。在10～200 μg/L的添加水平内4 种六六六、2 种滴滴涕和7 种指示性多氯联苯的线性关系良好,相关系数均大于0.999。方法的检出限（RSN=3）范围为1.12～3.89 μg/kg,定量限（RSN=10）范围为3.73～12.97 μg/kg。添加10、20、100 μg/kg 3 个水平的4 种六六六、2 种滴滴涕和7 种指示性多氯联苯于鸡蛋液、咸蛋及皮蛋空白样品中,加标回收率范围为78.04%～105.05%,相对标准偏差范围为1.28%～7.55%。该方法操作简便快速、准确、灵敏,适用于蛋及蛋制品中六六六、滴滴涕和指示性多氯联苯残留量的快速测定。     

加速溶剂萃取-气相色谱法检测鱼粉中7种指示性多氯联苯方法研究

目的 建立采用加速溶剂萃取-气相色谱检测鱼粉中7种指示性多氯联苯残留的方法。方法 采用加速溶剂萃取法, 以正己烷-二氯甲烷(1:1, V:V)为提取剂对鱼粉样品进行提取, 提取温度为120 ℃, 压力为10 MPa, 静态提取时间为8 min, 循环提取2次。用浓硫酸进行净化后, 用气相色谱法进行分析测定。结果 多氯联苯在5~500 ng/mL浓度范围内线性关系良好, 相关系数为0.9986~0.9999, 方法定量限为3.0~5.0 μg/kg, 3个添加水平的平均回收率为85.5%~104%, 相对标准偏差为2.61%~8.26%。结论 本方法精密度好, 准确度高, 操作简单、快速, 适用于鱼粉中多氯联苯的定量检测。     

分散固相萃取-气相色谱法测定水产品中多氯联苯

建立气相色谱批量测定水产品中7 种多氯联苯残留的分析方法。样品前处理采用超声波提取,经浓硫酸磺化后引入分散固相技术进行净化,考察不同条件下多氯联苯的提取分离效果并考虑水产品基质干扰的因素,利用气相色谱-电子捕获检测器测定7 种多氯联苯含量,采用内标校正。结果表明：7 种多氯联苯在0.005～0.2 μg/mL质量浓度范围内具有良好的线性关系,相关系数0.999 86～0.999 97;样品中添加量为2～100 μg/kg时,回收率为80.4%～118.0%,相对标准偏差为1.9%～7.3%,检出限为（RSN=3）0.4～0.8 μg/kg,定量限（RSN=10）1.3～2.7 μg/kg。该方法操作简单、方便快速、重复性好,适用于批量监测水产品中多氯联苯残留的分析。