碱提取-丙基化衍生法同时测定土壤中的甲基汞和乙基汞

建立了碱提取-丙基化衍生方式同时测定土壤中甲基汞和乙基汞的方法。优化了仪器分析条件，研究了碱提取温度、提取时间、缓冲溶液加入量和衍生化试剂加入量对测定结果的影响。应用本方法对5种实际土壤样品进行测定，甲基汞和乙基汞的方法检出限分别为0.5 μg/kg和0.3 μg/kg，相对标准偏差分别为1.3%~17%和0.94%~16%，平均回收率分别为88.2%~110%和66.1%~110%。该法适用于批量土壤样品中甲基汞和乙基汞的分析测定。     

柱后衍生离子色谱法测定土壤和沉积物中的六价铬

采用加热回流提取、柱后衍生离子色谱法分离土壤和沉积物中的六价铬，使用紫外可见检测器进行测定。选用7种土壤和沉积物的实际样品，依次讨论了氢氧化钠-碳酸钠溶液、碳酸氢钠溶液、氢氧化钠-氯化钾溶液、离子色谱碱性淋洗液4种不同提取剂对六价铬的提取效率，以及超声提取、水浴振荡提取和恒温磁力搅拌冷凝回流3种提取方式的提取效果；研究了10～60 min、25～190℃条件下的最佳提取时间和加热温度；分析了不同提取剂体积和称样量比值条件下六价铬标土的测定量，并探究了提取液的保存条件。优化后的前处理条件：称取2.5 g筛分后的土壤或沉积物样品，加入25 mL NaOH/Na₂CO₃提取剂，在恒温磁力搅拌冷凝回流装置上于120℃加热回流60 min,离心后用0.22μm滤膜过滤，用柱后衍生离子色谱紫外检测装置进行测定。相比目前常用的分光光度法、原子吸收法等测定土壤中六价铬方法，柱后衍生离子色谱法特异性强，降低了差减法或其他前处理技术测定六价铬时所引入的误差，且不受提取液色度、浊度等影响。方法检出限可达0.002 mg/kg,灵敏度高，操作简便，抗干扰能力强，对于...     

碱化保存淡水及海水样品测定甲基汞和总汞

本文研究了水样保存条件对汞分析物稳定性的影响。常规总汞分析酸化水样保存法只适用于保存寒冷冬季水样测定甲基汞,而夏季水样在酸化保存过程中甲基汞会转化为无机汞。碱化（ｐＨ＞１２）保存天然水样可以防止甲基汞无机化,并且同时适用于长期室温保存冬季和夏季水样测定甲基汞和总汞。聚氟塑料瓶、聚丙烯塑料瓶、聚乙烯塑料瓶和硼玻璃瓶均可用于保存碱化水样测定甲基汞,但只有前两种容器同时适用于总汞分析水样保存。本文认为天然水样中的微生物是水样保存过程中导致甲基汞无机化的主要因素。     

全自动甲基汞分析仪测定水和废水中甲基汞

建立了全自动甲基汞分析仪测定水和废水中甲基汞的方法,对较清洁的地表水和一般废水样品可直接衍生化测定,对基体复杂水样则需蒸馏后再衍生化测定。该法在水样中甲基汞含量为0~1 000 pg范围内线性良好,相关系数r为0.999 7,检出限为0.002 ng/L,标准参考物质测定结果均在参考值范围内,相对标准偏差为1.1%,加标回收率为83.2%~96.6%。该法适用于水及废水中甲基汞的检测。     

气相色谱法测定地表水中的甲基汞

采用气相色谱法测定地表水中的甲基汞。样品前处理采用琉基棉大量吸附样品中的甲基汞,富集倍数大、操作程序简单快速。色谱条件优化如下:毛细管色谱柱DB-1701,柱温为160℃,进样口温度为220℃,ECD检测器温度为250℃,尾吹(N2)60 mL/min,流速为1.0mL/min,分流比:10:1。测定结果表明,甲基汞的峰形尖锐,响应灵敏度高;取5L水样时最低检出限为0.1ng/L,加标样品测定的RSD为6.6﹪,回收率均为64.0%～78.4%。测定结果显示,该方法具有简便、快捷、准确、灵敏、重现性好等特点。     

水中苯胺类化合物分析的难点

结合实验研究了水中苯胺类化合物的测定难点和影响因素，包括样品保存和水样中悬浮物的影响。苯胺类化合物易被氧化，样品不易保存且受悬浮物的影响。研究结果表明：样品中未加入抗氧化剂进行保存时，部分苯胺类化合物迅速降解；当样品中加入80 mg/L硫代硫酸钠进行保存时，部分苯胺类化合物的保存时间可以延迟2~3 d后降解。样品中悬浮物对联苯胺萃取影响较大，回收率偏低，可以通过调节样品pH至酸性后过滤，再将滤液调至中性后进行萃取，回收率明显提高。笔者同时讨论了消除与补偿基质干扰的方法，包括色谱分离条件和检测器条件的选择、优化，内标法、空白基质匹配标准校正法和工作曲线法等定量方法的选择。     

气相色谱-质谱法测定沉积物中的有机氯和多氯联苯

采用加速溶剂萃取法提取沉积物中的有机氯和多氯联苯,提取液用凝胶色谱法净化后用气相色谱-质谱法测定。方法在5.00μg/L~200μg/L范围内线性良好,当取样量为10.0 g时,方法检出限为0.03μg/kg~0.37μg/kg,空白样品2个质量比水平的加标回收率为70.8%~121%,测定结果的RSD为2.7%~11.5%。用该方法测定实际样品,结果 12个抽检的沉积物样品中多氯联苯均未检出,9个样品中有机氯检出。     

4-AAP萃取光度法测定挥发酚的几点体会

介绍了在测定挥发酚过程中对试剂的保存，缓冲溶液pH值的控制，各种试剂的加入顺序及萃取时间的确定等问题的几点体会，并有针对性地提出了解决的办法。     

酸化吹气-气相分子法测定固体废物中硫化物

采用酸化吹气装置结合气相分子吸收光谱仪对固体废物中硫化物进行测定。考察酸性试剂的选取、加入量及酸化吹气反应时间对测定结果的影响,得出最佳的前处理条件为加入10 mL体积比为1∶1的磷酸,酸化吹气45 min。为确保吸收液中硫化物不被氧化,向吸收液中加入一定量抗氧化剂。结果表明:当抗氧化剂加入量为5 mL时,吸收液中硫化物的浓度可在6 h内保持稳定。方法的标准曲线相关系数为0.999 9,检出限为0.19 mg/kg,实际固体废物样品的相对标准偏差为2.7%～6.1%,加标回收率为91.0%～93.0%。将气相分子吸收光谱法和亚甲基蓝分光光度法进行比对,结果表明2种方法对固体废物中硫化物的测定无显著差异。     

用4—AAP萃取光度法测定挥发酚的几点体会

介绍了在测定挥发酚过程中对试剂的保存、缓冲溶液pH值的控制、各种试剂的加入顺序及萃取时间的确定等问题的几点体会，并有针对性地提出了解决的办法。     

兰州市冬季和春季PM2.5金属元素浓度水平与分布

为了解兰州市大气PM2.5中金属元素的污染水平和分布,于2013年冬季和春季在兰州市区4个在线监测点进行PM2.5样品采集,利用ICP-MS分析金属元素浓度。结果表明,Pb、B元素含量高于200 ng/m3,V、Fe元素含量在100~200 ng/m3,其余元素含量低于100 ng/m3,其中Pb含量最高,平均含量达到373.8 ng/m3.各监测点元素含量在冬季和春季各有不同,整体上是冬季高于春季。金属元素在兰州市区的空间分布与兰州市工业排放和气象因素有关,工业排放为主导因素。     

太原市冬、夏季醛酮化合物污染特征及来源分析

针对太原市空气臭氧污染较为严重的问题,开展臭氧主要前体物醛酮化合物质量浓度及其变化规律研究.利用2,4-二硝基苯肼固相吸附/高效液相色谱方法,通过对太原市2019年冬季和夏季大气的醛酮化合物进行分析,发现太原市冬季总醛酮化合物的平均质量浓度为13μg/m3,低于夏季的27μg/m3.其中甲醛、乙醛和丙酮质量浓度最高,且...     

Pesticides and Nitrate in Groundwater and Rainwater in the Province of Limburg in The Netherlands

The purpose of this study was to investigate the occurrence ofhigh levels of pesticides in groundwater and rainwater in TheProvince of Limburg in The Netherlands. In groundwater samplesin particular the presence of triazines – atrazine, simazine and propazine – was observed; besides these pesticides, dieldrin has also been observed. Atrazine and simazine were found to exceed the groundwater standard of 100 ng L^-1. In the rainwater samples, the presence of 13 of 23 different analyzed pesticides was observed. A number of pesticides werefound in high concentrations; e.g. atrazine (>200 ng L^-1). Two pesticides detected in rainwater (+-HCH and atrazine) were found to exceed the groundwater standard. Seven pesticides in rainwater were found to exceed the target value and three pesticides the maximum tolerable risk value (DDT, heptachlor and heptachlorepoxide A), which are used as ecotoxicological standards in The Netherlands.Nitrate in 15 of 16 analyzed natural springs was found toexceed the guideline value for nitrate in drinking waterof 50 mg L^-1, up to levels of about 200 mg L^-1. Nitrate concentrations in rainwater samples were observed up to 4.5 mg L^-1. A risk analysis of exposure to high pesticide levels in groundwater or rainwater has been performed using the model HESP. For atrazine levels due todeposition of rainwater in two different locations, exceedance of the T.D.I. level of 0.5 g kg^-1 day^-1 based on WHO criteria was observed for children using both an urban and a rural scenario and use of groundwater as drinking water.     

Organochlorine insecticide residues in drinking and ground water in and around Delhi

A multiresidue method was developed for the estimation of 15organochlorine pesticides in water. 50 samples of drinking watersupplied by the Municipal Corporation to the residential areasof Delhi and 20 ground water samples from nearby villages usedfor irrigation were monitored for the presence of organochlorineinsecticides by the method developed. Although, organochlorinepesticides were detected in the ground water and irrigationwater samples, the levels of pesticides were below the MaximumContaminant Level as prescribed by WHO. No organochlorineinsecticides were detected in any of the drinking water samples.     

Long-term changes in acidity and DOC in throughfall and soil water in Finnish forests

The main objective of this study was to examine if any detectable trends in dissolved organic carbon (DOC), sulphate (SO₄-S) concentrations and acid neutralizing capacity (ANC) in throughfall (TF) and soil water (SW) could be found during 1990–2010 and to relate them to recent changes in decreased acid deposition. The study was conducted in seven boreal coniferous forest sites: four of which are managed and three unmanaged forests sites. Generally, temporal trend showed a significant decrease in SO₄-S concentrations in bulk precipitation (BP), TF and SW. At some of the sites, there was an increasing tendency in BP and TF in the DOC concentrations. This feature coincides with decreasing SO₄-S concentration, indicating that SO₄-S may be an important driver of DOC release from the canopy. However, a slightly increased temperature, larger senescing needle mass and consequently increased decaying activity in the canopy may partly explain the increasing trend in DOC. In SW, no consistent DOC trend was seen. At some sites, the decreased base cation concentrations mostly account for the decrease in the ANC values in SW and TF.     

宽甸土壤及部分农作物中硼的分布及污染分析

用ICP-MS测定了辽宁宽甸23个土壤样品中的硼。背景地区和污染地区的土壤硼含量分别在 39.2～82.4mg/kg和133～1195mg/kg之间。其中硼矿开采区的土壤硼含量高达1195mg/kg。还用同样的方法分析了背景地区和污染地区几种农作物中硼的含量,结果表明,背景地区的大豆、土豆、玉米和豆角的硼含量(干基)分别为:37.4～47.9、5.8～6.3、24.4～25.5和1.24～2.74mg/kg,而污染地区相应农作物的硼含量分别为:34.0、12.0～12.8、40.7和2.48～2.64mg/kg。     

郑州大气及颗粒物中多环芳烃的分布特征与来源解析

对2012年郑州市大气中气态和颗粒态多环芳烃(PAHs)的分布特征与来源进行了分析。结果表明,ρ(∑PAHs)(包括气相与颗粒相)为23.27~194.61 ng/m3,气相中∑PAHs高于颗粒相,四环以下的PAHs大都存在于气态中;在夏、春2季,较小分子质量(≤178)的PAHs占比较高,冬季,较大分子质量(≥252)的PAHs占比明显较高;各功能区ρ(PAHs)排序为工业区交通密集区医疗、文化、行政混合区。郑州大气和颗粒物中PAHs可能主要来自煤和液体燃料(汽油柴油)的燃烧。     

大同市地表水及工业废水中氯苯和酚类化合物的监测

对流经大同市的主要河流和重点工业污染源所排放废水中的氯苯和酚类化合物做了分析测定.对酚类化合物的测定方法进行了改进.研究表明,大同市污染源对御河氯苯类污染物贡献较小,焦化厂酚类化合物排放量较高.     

Pesticides and Trace Metals Residue in Grape and Home made Wine in Jordan

Sixty home made wine and sixty-four grape samples were collectedfrom five territories in Jordan, where grapes and wine aremostly producted. The collected samples were analyzed for themost used organochlorine pesticides (OCP) and organophosphorouspesticides (OPP) in Jordan, as well as for four heavy metals(Ni, Cu, Zn and Pb). The results showed that OCPs residues weredetected in 73% of the wine samples but no OPPs residue weredetected which is due to generally shorter half life of thelater pesticide. Grapes showed higher incident of contaminationthan wine, however, OCPs and OPPs with both short and longhalf-lives were detected. The OPPs were detected in only8.3% of the analyzed grape samples. Heavy metals showed higher valuesin grapes than in the wine samples and it was attributed toremoval of solids during wine preparation processes or throughcontamination of wine during storage. Most of the samples werebelow toxic limit.     

Organochlorines and Mercury in Waterfowl Harvested in Canada

Samples of breast muscle from 32 species of waterfowl collected from 123 sites across Canada were analyzed for chlorobenzenes (CBz), chlordane-related compounds (CHL), hexachlorocyclohexanes (HCH), DDT, mirex, dieldrin, PCBs and mercury. ΣDDT, ΣCBz and ΣPCB were the compounds most frequently found above trace levels. ΣHCH and ΣMirex were detected the least often. Mercury was detected in all of the mergansers, over 50% of dabbling, bay and sea ducks, and in less than 2% of the geese analysed. The highest levels of contaminants were generally found in birds feeding at higher trophic levels such as sea ducks and mergansers. With the exception of a few samples of mergansers and long-tailed ducks from eastern Canada, which contained ΣPCB concentrations of 1.0–2.4 mg kg⁻¹, ΣPCB levels were less than 1 mg kg⁻¹ wet weight. Only one merganser from eastern Canada had a ΣDDT concentration (2.6 mg kg⁻¹ ww) which was greater than 1 mg kg⁻¹ ww. The highest ΣCHL (0.10 mg kg⁻¹ ww) was also found in mergansers from eastern Canada. Levels of total mercury in breast muscle were either low (< 1 mg kg⁻¹ ww) or below detection limits with the exception of a few samples of mergansers from eastern Canada which contained mercury concentrations of 1.0–1.5 mg kg⁻¹ ww. Health Canada determined that the organochlorine and mercury levels found in samples of breast muscle of ducks and geese analysed in this study did not pose a health hazard to human consumers and therefore these waterfowl were safe to eat.