水和废水中2,4—滴,2,4—二氯酚,2,4,6—三氯酚的测定

用Ｕｌｔｒａ－２，３２０μｍ柱分离２，４－滴，２，４－二氯酚肽２，４，６－三氯酚，保证了检测结果有足够的精确度，用直接进水样技术而不必处理水样，使检测结果趋精确。     

离子色谱法同时测定水中的SeO_3~（2－）和SeO_4~（2－）

用抑制型离子色谱法探讨了ＳｅＯ３（２）和ＳｅＯ４（２－）等七种阴离子的洗脱行为，讨论了共存阴离子的干扰及其消除，建立了测定水中ｓｅＯ３（２－）和ＳｅＯ４（２－）等阴离子的方法．ＳｅＯ３（２－）和ＳｅＯ４（２－）的检测限分别为４０μｇ／Ｌ和５０μｇ／Ｌ．     

新试剂4－（2－喹啉偶氮）－1，3－二羟萘分光光度法测定水中镉

研究了镉（Ⅱ）与４－（２－喹啉偶氮）－１，３－二羟萘（２－ＱＡＤＶＭ）的显色反应。结果表明：在０．３ｍｎｏｌ／Ｌ氢氧化钠溶液中，当有十二烷基（２－羟乙基）二甲基氯化铵（ＤＥＭＡＣ）存在时，镉（Ⅱ）与２－喹啉偶氮形成１：２橙红色络合物，λ_ｍａｘ为５１０_ｎｍ，摩尔吸光系数ε＝１．２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，镉的浓度的在０～２０μｇ／（２５ｍＬ）范围内符合比尔定律，用２－喹啉偶氮作显色剂，可直接测定废水中的镉。试样用标准加入法测得回收率为９６％～１０４％，相对标准偏差小于３％，用此法与双硫腙分光光度法对模拟镀镉废水进行了对比试验，其相对误差小于４％。     

水中微量五氯酚的气相色谱法测定

提出ＧＣ－ＦＣＤ分析方法测定水中微量五氯酚残留量。水样经萃取分离、衍生后，采用石油醚提取醋酸五氯酚酯，然后进入色谱柱，柱内填充２％ＯＶ－１７＋２％ＱＦ－１／ＣｈｒｏｍｏｓｏｒｂＷ－ＨＰ（８０～１００目），柱温２００℃，Ｎ＿２流量８０ｍＬ／ｍｉｎ，五氯酚酯３ｍｉｎ内出峰，最低检测浓度为０．１μｇ／Ｌ，各种样品回收率均在９０％以上，样品测试结果满意，可用于多种水体中微量ＰＣＰ残留量的测定。     

异相平衡流动注射分光光度法测定水中痕量SO^2—4

根据异相平衡的原理,确立了用流动注射分光光度法测定水样中痕量ＳＯ＾２－４的新方法。利用Ｂａ（Ⅱ）与偶氮氯磷Ⅲ的二元络合显色反应及ＢａＳＯ４＝Ｂａ＾２＋＋ＳＯ＾２－４进入微溶化合物ＢａＳＯ４反应柱前后吸光值的改变,从而求得ＳＯ＾２－浓度。表观摩尔吸光系数ε＝２．３＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,ＳＯ＾２－４检的线性范围为０－４０ｍｇ／Ｌ,检测限为０．８０ｍｇ／Ｌ,相对标准偏差为１．２％,试     

离子色谱法测定水中F~－，Cl~－，NO_3~－和SO_4~(2－)的实践

报导了用离子色谱法同时测定水中Ｆ~－，Ｃｌ~－、ＮＯ_3~－和ＳＯ_4~（2－）的最佳分析条件；研究了各组分测定的精密度，准确度，检测限和线性范围。用本法分析样品，获得了满意的结果。     

4－AAP法测定挥发酚中的萃取操作

４－ＡＡＰ法测定挥发酚中的萃取操作邹全忠，于清（河南信阳地区环境监测站，信阳４６４０００）准确加入三氯甲烷后加塞，稍用力振摇１－２次，将分液漏斗转为直立，开塞放气；加塞，较上次稍加力振摇２－３次，仍将分液漏斗直立，放气。如此放气４－５次，感到气流已很...     

发生氢气分离离子色谱法间接测定水中硫化物

利用ＫＢＨ４在酸性条件下分解产生的氢气为载气分离水中硫化物，用ＮａＯＨ—Ｈ２Ｏ２溶液吸收Ｈ２Ｓ，并将其氧化为ＳＯ２－４，用离子色谱法测定ＳＯ２－４。方法用于各种水样中硫化物的测定，相对标准偏差为１．５８％，回收率在９０．５％到９８．２％之间。方法适用于水中硫化物的测定     

液上空间－气相色谱法测定工业废水中1，1，1－三氯乙烷等卤代烃的研究

本方法研究了液上空间气相色谱法测定工业废水１，１，１－三氯乙烷、四氯化碳、三氯甲烷三种挥发性卤代烃，采用填充气相色谱法以角鲨烷为固定液，用ＣｈｒｏｍｏｓｏｒｂＧＡＷ－ＤＭＣＳ作为担体，在选定的条件下，１，１，１－三氯乙烷、四氯化碳、三氯甲烷能完全分离．同时也能与经常共存的二氯甲烷、三氯乙烯、四氯乙烯、一氯二溴甲烷、三溴甲烷完全分离而互不干扰。本方法的定性检出限是按全程序空白值标准偏差的３倍值计算。１，１，１－三氯乙烷、四氯化碳、三氯甲烷的定性检出限分别为２．４×１０－２ｎｇ、２．１０×１０－４ｎｇ、０．１３ｎｇ，当进样量为２０ｕｌ时，１，１，１－三氯乙烷、四氯化碳、三氯甲烷的最低检出浓度分别为１．２×１０－３ｍｇ／１、１．０８×１０－５ｍｇ／１、６．４８×１０－３ｍｇ／ｌ。     

消解仪－麝香草酚分光光度法测定水中总氮

采用消解仪替代高压蒸汽灭菌器消解水样,用麝香草酚分光光度法替代紫外分光光度法测定总氮.试验表明,方法在0mg/L～10.0mg/L范围内线性良好,相关系数R为0.9999;方法检出限为0.04mg/L;测定低、中、高质量浓度的标准溶液,RSD为1.1% ～5.5%;对3份实际水样进行加标回收试验,回收率为94.6% ～98.2%,测定总氮标准品,结果在保证值范围内;用该方法与国标方法同时测定水样,测定结果的相对偏差〈5%.     

2,4-滴、灭草松和多种酚类的快速检测方法探讨

采用Waters Oasis HLB柱分离富集水样,用超高效液相色谱法同时测定水中2,4-滴、灭草松和7种酚类。通过优化试验条件,使方法在0. 03 mg/L～10. 0 mg/L范围内线性良好,方法检出限为0. 03μg/L～0. 12μg/L,自来水水样的回收率为84. 4%～109%,RSD为0. 8%～3. 7%。     

Combined toxicity of three chlorophenols 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol to Daphnia magna

The toxicity of single and combined mixtures of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) to Daphnia magna was studied. The toxicity ranking of these three single chlorophenols (CPs) to Daphnia magna was PCP > 2,4-DCP > 2,4,6-TCP. The toxic units (TU) approach was used to estimate the combined effects in experiments, the median effective concentration (EC(50)) values were 0.87-1.21 and 0.46-0.59 for binary and ternary mixtures, respectively. Response surface models of General Linear Models (R(2) > 0.90, residual deviation < 3.25) were established for all three binary mixtures. The toxicity for ternary mixtures based on the EC(50)-value and 10% effective concentration (EC(10))-value fixed mixture ratio presented a synergism. The risk based on the single CP's toxicity test may be underestimated. In addition, four approaches (concentration addition, toxicity equivalency factors, effect summation, and independent action) were used for the calculation of combined effects of the mixture. The experimental results showed that concentration addition and toxicity equivalency factor approaches were effective methods for calculation of additive effects of mixtures from binary systems of CPs; while independent action and effect summation (low simulated tail) predicted lower toxicity than experimental results. Limitations of the traditional focus on the effects of single agents were highlighted; hazard assessments ignoring the possibility of joint action of CPs will almost certainly lead to significant underestimations of risk.     

Dissipation and residue of 2,4-D isooctyl ester in wheat and soil

A simple analytical method was developed to determine the 2,4-D isooctyl ester residue in wheat and soil by gas chromatography coupled with electron capture detector. Using the method, the dissipation and residue of 2,4-D isooctyl ester in wheat field was investigated. The average recoveries of 2,4-D isooctyl ester ranged from 80.1% to 110.0% with relative standard deviations of 2.4% to 16.1%. The pesticide showed a rapid dissipation rate either in wheat seedling or soil, with the half-lives of 1.0 to 3.0 days. The terminal residue results in wheat grain were much lower than the codex MRL (2.0 mg/kg). It could be considered safe to food and environment when using this herbicide for controlling weeds in wheat field.     

Kinetics of Biotransformation of 2,4-Dichlorophenol using UASB-Reactor

Chlorophenol compounds are environmental pollutants that are both anthropogenic and xenobiotics. Some of these chemicals are carcinogens and are both toxic to a number biochemical processes. Biotransformation of 2,4-dichlorophenol (2,4-DCP) was studied in the presence of glucose on an upflow anaerobic sludge blanket reactor (UASB) using mixed culture. A continuously operated UASB reactor was employed using mixed synthetic wastewater. Results obtained from the 1.8 L volume capacity UASB reactor were subjected to kinetic evaluation constants. Results indicate that the degradation of 2,4-DCP in the presence of glucose was strongly influenced by the concentration of the compound. High degradation levels were observed when the concentration of 2,4-DCP was in the range of 50-150 mg L(-1). Concentrations of 2,4-DCP above 160 mg L(-1) were toxic to microbes even in the presence of glucose. The maximum degradation of 2,4-DCP was found to be 70.4% when initial concentration of 2,4-DCP was 124 mg L(-1) and glucose concentration of 500 mg L(-1) at hydraulic retention time of 13.2 hr. The biodegradation followed first order reaction kinetics with a rate constant (K) of 0.67, Vmax of 0.244 kg m(-3) day(-1), Ks of 0.117 kg m(-3) day(-1) and correlation coefficient of 0.766.     

2,4-二硝基苯腙的色谱分离分析条件的研究

合成了甲醛的衍生物—２,４二硝基苯腙,对其结构与纯度进行了鉴定;应用气相色谱研究了其在四氯化碳溶液中的色谱分离分析性质,结果表明,将之作为标准品用于空气中甲醛的分析是可行的。     

A spectrophotometric assay method for vanadium in biological and environmental samples using 2,4-dinitrophenylhydrazine with imipramine hydrochloride

A simple, rapid, and sensitive method involving the interaction of 2,4-dinitrophenylhydrazine with imipramine hydrochloride in presence of vanadium (V) in sulfuric acid medium has been proposed for the determination of vanadium. The purple-colored product developed showed an absorption maximum at 560 nm and was stable for 24 h. The working curve was linear over the concentration range of 0.1–2.8 μg ml^− 1, with sensitivity of detection of 0.0124 μg ml^− 1. Molar absorptivity and Sandell’s sensitivity were found to be 2.6 × 10⁴ l/mol cm and 0.0039 μg cm^− 1, respectively. The accuracy of the proposed method was assessed by Student’s t test and variance ratio F test, and the results were on par with the reported method. The method was successfully used in the determination of V in water, human urine, soil, and plant samples, and it was free from interference by various concomitant ions.     

Quantitative determination of hexamethylene diisocyanate (HDI), 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI) monomers at ppt levels in air by alkaline adduct coordination ionspray tandem mass spectrometry

Occupational exposures to isocyanates can lead to occupational asthma. Once sensitized, some workers could react to isocyanate monomers at concentrations below 1% of the Permissible Exposure Limit of 5 ppb in air. Currently available methods are not sufficiently sensitive to adequately evaluate isocyanates present at these levels in workplace air. This article describes a novel method for isocyanate determination allowing the ultratrace quantification in workplace air of hexamethylene diisocyanate, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate monomers. Sampling is performed during a complete workshift at a flow rate of 1 L min(-1) with a cassette containing a 1-(2-methoxyphenyl)piperazine-impregnated 25 mm filter. Analysis is performed using liquid chromatography hyphenated with coordination ionspray tandem mass spectrometry. The analytical method's linearity was measured for a concentration range varying from the limit of detection of 0.04-0.13 ng mL(-1), depending on the monomer, up to approximately 32 ng mL(-1) for every isocyanate monomer, all with correlation coefficients (R(2)) greater than 0.999. The analytical method's lower limit of quantification combined with an adapted sampling strategy allow the quantification of isocyanate monomers down to 0.04 ppt for an 8 h work shift when a lithium adduct is used, which is more than 300 times lower than the most sensitive method currently available. This novel method can be used to confirm the very low level of isocyanate monomers for the safe reassignment of sensitized workers and it is also useful for charting the isocyanate dispersion tail in workplace environments.     

Monitoring for 2,4-residues in fish species resident in treated lakes in east-central Ontario 1977–80

Authorized use of 2,4-D by cottage owners in Buckhorn Lake for the years 1977 to 1980 ranged from 124 to 280 kg of active ingredient, annually. This would give predicted average water concentrations of 2 to 4 g L^–1 during the June–July period. However, higher residues were observed in the Lake. Between 1977 and 1980, 353 individual fish, of eight species, were caught for analysis in Buckhorn and Chemong lakes. These fish belonged to eight edible species. Twelve percent of the fish caught during the pre-treatment period (i.e. May), had detectable residues of 2,4-D. Mean residues by species and year ranged from <5 to 30 g kg^–1 2,4-D. In the early post-treatment period (i.e. July), 69% of fish caught had mean residues by species which ranged from <5 to 136 g kg^–1 2,4-D. In the late post-treatment period (i.e. October), 19% of fish caught by year had detectable residues of 2,4-D. Mean residues by species during this period ranged from <5 to 60 g kg^–1 2,4-D. While 15 (i.e. 4%) of the 353 fish and fish composites had 2,4-D above the maximum residue limit of 100 g kg^–1 only six were of edible size.     

5—(4—磺酸基苯偶氮)8—(2,4—二硝基苯氨基)喹啉测定食品中铜的研究应用

在弱碱性介质中 ,5— (4—磺酸基苯偶氮 ) 8— (2 ,4—二硝基苯氨基 )喹啉 (SPDNPAQ)与铜反应生成 2∶ 1紫红色络合物 ,体系 λmax=56 0 nm,ε=1.2 3× 10 5L· mol-1· cm-1。铜含量在 0～ 0 .4 mg/ L内符合比耳定律 ,方法用于一些生物样品和水样中铜的测定。