地下水电导率与溶解性总固体相关性探讨

在环境样品的分析中,电导率和溶解性总固体是经常检测的项目。电导率是电导池常数与溶液电阻的比值,是以数字表示溶液传导电流的能力。溶于水中的各种离子都具有一定的导电能力,其电导率见表１［１］。可溶性离子越多,电阻就越小,电导率就越大。溶解性总固体是水样经...     

水溶性卟啉分光光度法间接测定环境样品中痕量黄原酸盐

黄原酸盐的测定方法很多,如容量法,电导滴定法、紫外光谱法,比色法,极谱法和气相色谱法等等。但这些方法的灵敏度均较低,远不能达到地面水中黄原酸盐的卫生排放标准所要求的检测下限。近年来,已有文章报导,比色法测定黄原酸盐的检测下限可降至2PPb但取样体积过大仍是这一方法的不足之处。本文提出了一种痕量黄原酸盐的间接分光光度测定法,应用于环境样品分析,取得了满意的结果。     

环境样品稀释方法的探讨

环境样品，特别是污染源样品，在监测分析中经常要对污染物含量较高的样品进行稀释，使稀释后详品中污染物的浓度量分析方法测定浓度范围内。采取科学的稀释方法，确定适当的稀释份数，不仅可减轻分析工作量，节约分析成本，而且可降低样品中干扰物质的浓度，降低稀释误差，提高监测结果的可靠性。1样品稀释方法及其选择样品的稀释方法很多，本文便讨论根据样品稀释时使用的样品预处理程度分类。如原始样品稀释法，中同样品稀释法，分析后样品稀释法等．1．1原始样品稀释法需要稀释的环境样品中，均可采用原始样品稀释法。原始样品稀释法根…     

离子色谱法测定大气降水中的硫酸根和硝酸根离子

降水样品中的阴离子,经阴离子色谱柱交换分离,抑制型电导检测器检测,以保留时间定性,峰面积外标法定量,建立了离子色谱同时测定降水的硫酸根和硝酸根离子的分析方法。结果表明,2种阴离子标准曲线线性相关系数均大于0.9991,测定结果的相对偏差(n=10)分别是0.81%和0.89%。用该方法对样品进行测定并进行加标回收试验,加标回收率在98.0%～101.0%之间,能满足大气降水中阴离子的分析要求,是降水样品中阴离子分析的理想方法。     

电导和直流安培双检测器离子色谱法测定清洁水样中的碘化物

选用配备了2种不同检测器(电导检测器和直流安培检测器)的离子色谱仪对稀释后过0.22μm滤膜的水样进行分析。配备有直流安培检测器的离子色谱仪测定水中碘化物的方法在0.100~20.0μg/L范围内线性关系良好,相关系数(r)=0.9999,方法检出限为0.030μg/L,测定下限为0.120μg/L,样品加标回收率为95.0%~104%,相对标准偏差为1.06%~1.64%;配备有电导检测器的离子色谱仪测定水中碘化物的方法在20.0~2.00×105μg/L范围内线性关系良好,相关系数(r)=0.9995,方法检出限为2.00μg/L,测定下限为8.00μg/L,样品加标回收率为99.0%~110%,相对标准偏差为0.71%~3.12%。离子色谱-直流安培检测器法测定水中碘化物的方法准确度高、灵敏度高、精密度好,检出限相对较低,适用于测定ρ(碘化物)≤20.0μg/L的清洁水样;离子色谱-电导检测器法主要适用于测定ρ(碘化物)≥20.0μg/L的水样。     

在线监测氨氮浓度的电导测量方法研究

建立了适用于氨氮在线监测的干法蒸馏-电导法和湿法蒸馏-电导法。该方法是通入一定流量的气量于含氨试样中,全沸腾加热,蒸发出的氨和水蒸气一起经冷凝器后,进入酸吸收液中。酸吸收液的电导率随氨氮蒸馏液的吸收发生变化,其变化的值和样品中氨氮的浓度呈一定的比例关系。研制出的氨氮在线监测仪结构简单,运行稳定可靠,测量结果准确。     

环境样品中铅、锑、汞、硒形态分析研究进展

综述了环境样品中铅、锑、汞、硒形态分析的研究进展,以及光谱法、色谱法、毛细管电泳及其联用技术在形态分析中的应用,展望了环境样品痕量元素形态分析的发展前景。     

微波能加热技术在消解环境样品中的应用

微波能加热技术在消解环境样品中的应用黄图强（四川省沪州市环境监测站６４６０００）当今，环境分析工作者在使用现代分析仪器进行环境样品的分析时，样品的测定过程一般仅需要几分钟，十几分钟。而一个环境样品的消解过程往往则需要几十分钟，甚至几小时。环境样品的复...     

环境样品中~(237)Np的ICP-MS分析研究进展

近年来,环境样品中237Np的准确测量受到越来越多的关注。随着质谱技术的发展,电感耦合等离子体质谱(ICP-MS)成为研究和测量环境样品中237Np的重要手段。文章从样品制备、定量方法、干扰降低、进样系统改进、与色谱联用等方面,对ICP-MS分析环境样品中237Np的研究进展作了评述。     

国家环境标准样品在环境有机污染物分析中的应用

简介了在分析环境中的有机污染物时,标准样品作为替代物、基体加标物在样品前处理中的应用,及其作为仪器性能检验物、校正物、内标物在样品分析过程中的应用。     

Use of denuder/filter apparatus to investigate terpene ozonolysis

A denuder/filter apparatus was used to collect the gaseous and particulate reaction products from ozonlysis of α-pinene, limonene and α-terpineol in an effort to develop sampling techniques for characterizing indoor environment chemistry. Carboxylic acids found in the particulate phase were derivatized to 2,2,2-trifuoroethylamides by reaction with 3-ethyl-1-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC) and 2,2,2-trifluoroethylamine hydrochloride (TFEA). Carbonyl compounds collected in both gas phase and particulate phase were derivatized to their respective oximes by reaction with O-(2,3,4,5,6-pentafluoro-benzyl)hydroxylamine hydrochloride (PFBHA). The ozonolysis of α-pinene yielded the carboxylic acids: cis-pinonic acid and pinic acid and the proposed carboxylic acids methanetricarboxylic acid and terpenylic acid; the carbonyls: 4-oxopentanal, norpinonaldehyde, pinon aldehyde and the proposed carbonyl methylidenepropanedial. The ozonolysis of limonene yielded the carboxylic acids: limonic acid and pinic acid and the carbonyls: 1-(4-methylcyclohex-3-en-1-yl)ethanone (4AMCH), glyoxal, methyl glyoxal, 4-oxopentanal and 6-oxo-3-(prop-1-en-2-yl)heptanal (IPOH). The ozonolysis of α-terpineol yielded the proposed carboxylic acids: terpenylic acid and homoterpenylic acid and the carbonyls: (5E)-6-hydroxyhept-5-en-2-one, methyl glyoxal and 4-oxopentanal.     

Measurement of total antimony and antimony species in mine contaminated soils by ICPMS and HPLC-ICPMS

This paper describes the measurement of total antimony and antimony species in "real world" mine contaminated sediments using ICPMS and HPLC-ICPMS. Low and high temperature microwave extraction procedures (90 degrees C and 150 degrees C, respectively) using a range of nitric-hydrochloric acid combinations were examined as to their efficacy to extract antimony from six mine contaminated soils and a certified reference material. The use of the higher temperature with nitric-hydrochloric acid (1:2 (v/v)) was suitable to release antimony from sediments and the certified reference material, NIST 2710 Montana soil. Antimony concentrations obtained using this acid mixture were similar to those obtained using a more aggressive extraction with nitric, hydrochloric, perchloric and hydrofluoric acid mixture. A 25 mM citric acid solution at 90 degrees C for 15 min extracted 47-78% of antimony from soils. A Hamilton PRP X-100 anion exchange column with 20 mM EDTA mobile phase, pH 4.5, flow rate 1.5 mL min(-1) and column temperature of 50 degrees C was used to separate antimony species. Column recoveries ranged from 78-104%. The predominant form of antimony was Sb(5+). Little conversion of Sb(5+) occurred (<5%) during extraction, however, significant conversion of Sb(3+) occurred (approximately 36%). The extraction of antimony species with citric acid should be useful in the determination of inorganic antimony available to plants, as plants commonly excrete carboxylic acids, including citric acid, into their rhizospheres to mobilise trace elements for nutritional purposes.     

Aerobic biodegradation of linear alkylbenzene sulfonates and sulfophenylcarboxylic acids for different salinity values by means of continuous assays

Aerobic biodegradation of linear alkylbenzene sulfonates (LAS) and sulfophenylcarboxylic acids (SPCs) in water, at different salinity values, has been studied. Three experiments have been carried out employing a staircase model system with continuous dosage of LAS to the system and using concentrations of LAS of the same order as those detected in littoral waters receiving urban wastewater discharges. LAS biodegradation was observed to be almost complete (showing a great extent), and in all cases exceeds 98.4%. At the very low concentration values of LAS utilized in the experiments, no significant variations in the biodegradation of LAS due to the effect of the different salinity values assayed were observed. The biodegradation intermediates detected for all the cases were sulfophenylcarboxylic acids with carboxylic chains of between five and 13 carbon atoms. The detection of C13-SPC (which is only produced by C13-LAS) confirms the existence of ω-oxidation. The total disappearance of SPCs in all cases indicates that mineralization of LAS at the concentrations tested was complete.     

Volatile metabolites from microorganisms grown on humid building materials and synthetic media

Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.     

Molecular characterisation of organic material in air fine particles (PM10) using conventional and reactive pyrolysis-gas chromatography-mass spectrometry

Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to study the composition of organic constituents in air particulate matter (PM10) collected inside an industrial area. A few milligrams of sampling filters containing air particles were pyrolysed at 700 degrees C directly (conventional) or after the addition of a derivatising reagent (tetramethylammonium hydroxide, TMAH, for pyrolysis-methylation; hexamethyldisilazane, HMDS, for pyrolysis-silylation). Py-GC-MS was also applied to synthetic polymers (poly(styrene-co-isoprene), polylimonene and polypinene) and vegetation samples (coniferous pollen, bark and resin) to identify markers indicative of possible precursors. Pyrolysates of PM10 showed the same suite of compounds in all the four seasons, dominated by hydrocarbons like styrene, limonene and clusters of isomeric alkenes with 14, 15 and 16 carbon atoms. Pyrolysis products of natural origin, including furaldehyde, benzeneacetonitrile, dehydroabietin and other diterpenoids were found, while no specific markers of synthetic rubbers were detected. The principal products released from reactive pyrolysis of PM10 were methyl or trimethylsilyl (TMS) derivatives of 1,6-anhydroglucose (levoglucosan), fatty acids, dehydroabietic acid and other resin acids along with hydroxy (di)carboxylic acids. Possible sources of the detected products (e.g. pine forest, biomass combustion) are discussed.     

Techniques and methods for the determination of haloacetic acids in potable water

Haloethanoic (haloacetic) acids (HAAs) are formed as disinfection byproducts (DBPs) during the chlorination of natural water to make it fit for consumption. Sundry analytical techniques have been applied in order to determine the concentrations of the HAAs in potable water supplies: gas chromatography (GC-MS, GC-ECD); capillary electrophoresis (CE); liquid chromatography (LC), including ion chromatography (IC); and electrospray ionization mass spectrometry (ESI-MS). Detection limits required to analyze potable water samples can be regularly achieved only by GC-ECD and ESI-MS. Without improvements in preconcentration or detector sensitivity, CE and LC will not find application to potable water supplies. The predominant GC-ECD methods use either diazomethane or acidified methanol to esterify (methylate) the carboxylic acid moiety. For HAA5 analytes, regulated under the EPA's Stage 1 DBP Rule, diazomethane is satisfactory. For HAA9 data gathered under the Information Collection Rule, acidified methanol outperforms diazomethane, which suffers from photo-promoted side reactions, especially for the brominated trihaloacetic acids. Although ESI-MS can meet sensitivity and selectivity requirements, limited instrumentation availability means this technique will not be widely used for the time being. However, ESI-MS can provide valuable confirmatory information when coupled with GC-ECD in a research setting.     

Tracking sewage derived contamination in riverine settings by analysis of synthetic surfactants

A study has been made of the presence and reactivity of the most commonly used surfactants, both anionic (linear alkylbenzene sulfonates, LAS, and alkyl ethoxysulfates, AES) and non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs), in water and surface sediments from the middle stretch of the Guadalete River in SW Spain (12 stations). Average values were between 0.1 and 3.7 mg kg(-1) in sediment, and between 0.2 and 37 μg L(-1) in water. The sorption of surfactants was dominated by hydrophobic mechanisms, so those homologues having longer alkyl chains (e.g. C(18)AEO) showed higher relative percentages and concentrations in sediments compared with water. Local and sharply higher concentrations of these compounds were observed at three sampling stations (7, 9 and 12), indicating the occurrence of wastewater discharges into the river. By analysing the distributions of different surfactant homologues and their metabolites we were able to distinguish between sewage contamination from sources discharging treated and untreated wastewaters. Upstream (stations 1-2), LAS concentrations were below 30 μg L(-1) and the composition of their degradation intermediates (sulfophenyl carboxylic acids, SPCs) (160 μg L(-1)) was dominated by short-chain homologues (C(6)-C(9)SPCs), indicating that the degradation of this surfactant is at an advanced stage. The highest concentration (487 μg L(-1)) of SPCs was detected near the effluent outlet of a sewage treatment plant (STP) (station 12). Sampling stations (7 and 9) affected by untreated wastewater discharges were the only ones showing the presence of the most reactive and biodegradable SPC isomers and homologues (e.g. C(11)SPC). Here, LAS reached the highest concentration values measured (>2 mg L(-1)), and showed a homologue distribution closer to that of commercial mixtures than LAS found at the other stations.     

Multi-component analysis of polar water pollutants using sequential solid-phase extraction followed by LC-ESI-MS

A multi-component screening analysis method for polar to medium-polar water pollutants was developed. Sample clean-up and group separation are performed by sequential solid-phase extraction (SSPE) using automated SPE with C18 and polymeric sorbent materials. Analyses are performed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) using a single-quadrupole instrument. More than 90 priority compounds of environmental interest--comprising the most important chemical and substance classes: phenols, carboxylic acids, aromatic sulfonates, aromatic amines, pharmaceuticals, surfactants, dyes, and pesticides--have been chosen for the experiments. The compounds are divided by the SSPE procedure into 3 different polarity classes. The extraction recoveries were determined in the 3 fractions for every single substance, and were for most of the analytes in the range of 50-100%. A mixture of hexane-dichloromethane was used for the elution of nonpolar compounds like alkylphenols from C18. Methanol and acetone are well suited for the elution of more polar substances. The limits of detection (LODs) were determined for all compounds. Effluents from municipal and industrial wastewater treatment plants (WWTPs) treating waste water from textile industries; and the corresponding receiving waters (rivers and lakes) have been analysed with the developed method. Urban and industrial pollution was observed in rivers and streams in the area north of Milan, Italy. In the water samples different phenols (nitrophenols, bisphenol A, nonylphenol), alkylphenol ethoxylate surfactants, their metabolites with endocrine disrupting potential, aromatic sulfonates, linear alkylbenzenesulfonate surfactants, dyes, pesticides, pharmaceuticals, and a dichlorobenzidine compound were identified.     

Study of odor compounds in gaseous effluents generated during production of poultry feather and viscera meal using headspace solid phase microextraction

This work reports the screening and characterization of odor compounds in gaseous effluents generated during the production of poultry feather and viscera meal, the by-products of the poultry meat industry. Chemical analysis was carried out by solid phase microextraction in the headspace (HS-SPME) mode. Exhaust air of thermal processing of poultry feather and viscera were sampled online from a bench-scale digester, condensed, and collected in sampling flasks. Both volatile and semivolatile organic compounds present in the condensed gases were extracted under agitation at constant temperature. The extracts were analyzed with a gas chromatograph coupled to a mass spectrometric detector (GC/MSD). The identification of compounds was carried out by comparing the mass spectra obtained with those from the Wiley library and quantification was accomplished through authentic analytical standards. For the determination of the best extraction conditions and analysis, extraction fibers of different coatings and polarities were tested: divinylbenzene/carboxen/polydimethyilsiloxane (DVB/CAR/PDMS), carbowax/divinylbenzene (CW/DVB), and polydimethylsiloxane (PDMS) and chromatography columns of different polarities: DB-WAX (polar) and DB-5 (nonpolar). The best extraction conditions and analysis of the compounds of interest were obtained by the use of the SPME fiber with DVB/CAR/PDMS coating and analysis by GC/MSD with polar capillary column. Several carboxylic acids were identified, as well as mercaptans, amines, and aldehydes of great environmental importance.