双系统离子色谱法检测水中硫化物、氰化物、总磷和总氮

针对水中硫化物、氰化物、总磷、总氮标准方法检出限较高,存在检出即超标的风险,且需分开检测的问题,本文通过调整过硫酸钾和氢氧化钠的配比,并试验了过硫酸钾纯度以及加热消解方式对总磷总氮检测结果的影响,确定最优的消解条件,将水中的磷和氮氧化为磷酸盐和硝酸盐,与硫化物、氰化物采用离子色谱分别测定,结果同时输出。该方法在实验测定的浓度范围内硫化物、氰化物、总磷和总氮的相对标准偏差分别为1.370%～8.074%；硫化物、氰化物、总磷和总氮的检出限分别为 0.0003mg/L、0.0001 mg/L、0.01 mg/L、0.03 mg/L；对实际水样中加标回收率分别为95.40 %～107.80 %；与实验室现有检测方法方法相比,检测时间大幅压缩,提高了检测效率。本方法已经应用于水中硫化物、氰化物、总磷和总氮的检测,并与参考方法具有良好的一致性。经过扩展,该方法可用于白酒中硫化物和氰化物以及窖泥中总磷、总氮的检测。     

高温燃烧法测定水质总氮

通过高温燃烧法测定了水质总氮含量,与K2S2O8氧化-紫外分光光度法进行比较,高温燃烧法的测定结果准确可靠。方法的检出限为0.05 mg/L,测定下限为0.20 mg/L,样品测定的RSD为0.9%~4.6%,加标回收率为97.4%~103%。对于有悬浮物干扰的水样,可以超声粉碎后测定;Fe3+,Cr6+和卤素离子对高温燃烧法测定总氮无干扰。     

流动注射光度法测定水中总磷量

采用流动注射光度法测定了水中总磷量。水样经硫酸和过硫酸钾在125℃消解后,所得样品溶液中磷(PO_4~(3-))与钼酸铵生成杂多酸,经还原成钼蓝后测定其吸光度。总磷的质量浓度在1.0mg·L~(-1)以内与其吸光度呈线性关系,方法的检出限(3S/N)为0.003mg·L~(-1),测定下限(10S/N)为0.012mg·L~(-1)。方法用于测定水样中总磷的含量,相对标准偏差(n=7)在1.5%～3.0%之间,加标回收率在95.7%～102.5%之间。     

紫外消解流动注射光度法测定海水养殖废水中总氮、总磷

采用紫外消解–流动注射分光光度法测定海水养殖废水中总氮和总磷。总氮样品浓度在0.050~5.00mg/L范围内,总磷样品浓度在0.020~5.00 mg/L范围内均与峰高有良好的线性关系(r分别为0.999 90和0.999 94)。在盐度为35,进样时间为70 s,清洗时间为90 s的条件下,总氮和总磷的检出限分别为0.050mg/L和0.020 mg/L,测定结果的相对标准偏差分别为1.15%,0.60%(n=6),加标回收率分别为98.7%~101.2%和98.6%~102.5%。该方法能满足海水养殖废水中总氮和总磷的监测要求。     

高氨氮污水中总氮浓度检测方法改进

为了获得一种检测范围更宽、准确性更高又适合高氨氮污水的总氮测定方法,以养猪废水为研究对象,先采用蒸馏-中和滴定法(HJ537-2009)测定水中氨氮,再采用国标法(GB11894-89)测定蒸馏剩余液中除氨氮以外其他形态的氮,最后求两部分之和。新方法对KNO_3,NH_4Cl,C_2H_5NO_2的加标回收率分别为99%~102%,99%~101%,98%~102%,相对标准偏差为0.38%,检测范围为0.05~1000 mg/L,优于国标法。新方法可有效防止国标法中部分氨氮在碱性环境中转化为氨气逸出,从而提高总氮测定的准确性和精确度。     

连续流动分析法测定水中总磷、总氮比对研究

采用连续流动分析方法同时测定水和废水中总磷、总氮,验证连续流动分析方法的适用性。数据结果表明连续流动法测定总磷、总氮线性良好,相关系数均在0.9999以上,方法检出限分别为0.01、0.04 mg·L~(-1),实验室测定总磷、总氮标准溶液RSD分别在1.3%~2.6%,1.4%~6.0%之间,测定有证标准物质的结果在保证值范围内,实际水样的加标回收率分别为90%~108%,99%~104%。该方法与国标分光光度法同时测定多种类型的水样,比对实验结果表明两种方法无显著性差异。     

区带流动分析技术测定水中的总磷

建立区带流动分析技术快速测定水中总磷的方法。用双气泡隔断方法实现完全显色反应,通过智能除泡技术排除气泡干扰,采用便携式化学分析仪测定水样中的总磷含量。结果表明,总磷质量浓度在0.01～0.6 mg/L范围内与吸光度呈良好的线性关系,线性相关系数r~2=0.999 45,方法检出限为0.01 mg/L。测定结果的相对标准偏差为0.99%～1.64%(n=6),样品加标回收率为85.9%～113.0%。该方法准确度高,检测时间短,仪器携带方便,适合于现场监测及突发性污染事故的应急监测。     

碱性过硫酸钾氧化法-紫外分光光度法测定养殖海水中总氮量

以国家标准GB/T 12763.4-2007中的碱性过硫酸钾氧化法和GB/T 11894-1989中淡水总氮测定的紫外分光光度法为基础对海水总氮测定方法进行了改进。在改进的方法中减少了物质转化步骤,相应减少了样品转移次数与定量移取步骤。该方法测定总氮量的线性范围在57.74mg·L-1(以KNO3计)以内。该方法的有机氮物质氧化率为(99.1±5.6)%,加标氧化率为(100.4±4.2)%,以海水样品为基体的加标回收率为(107.3±15.3)%。对海水样品及20,40μmol·L-1硝酸钾标准溶液的测得结果与已知值无显著差异。     

全自动电位滴定法测定水中氯化物

为了实现快速准确测定水中氯化物含量,建立了一种全自动电位滴定法测定水中氯化物的分析方法,对取样体积进行了优化,结果表明本方法最佳取样体积为50mL。研究了CO32-、S2-、I-、Br-等对氯化物测定结果的影响,并就干扰离子的消除提出了有效的方法,水样中加入1 ml （2+98）硝酸溶液可消除S2-、CO32-的干扰,当水样中I-、Br-浓度高于5mg/L时仪器可自动校正并扣除干扰。本方法检出限为0.19mg/L,大大低于水质 氯化物的测定 硝酸银滴定法GB 11896-89中规定的10 mg/L的要求,该方法测定地表水、地下水和工业废水实际样品,精密度为1.9%～2.3%,加标回收率为91.9%～99.0%。采用全自动电位滴定法测定水中氯化物,方法检出限低、精密度和正确度良好。本方法的建立为复杂环境水样中氯化物的准确测定提供了有益的技术支撑。     

紫外光与臭氧结合消解-离子色谱法测定水质总磷

采用紫外光与臭氧结合消解水样,用离子色谱法测定水质总磷含量,色谱峰高与磷酸盐质量浓度在0-20mg／L范围内线性关系良好,检出限和测定下限分别0．008mg／L和0．03mg／L。此方法无需添加化学试剂,避免了标准分析方法中各种因素的影响,操作简单快速、省时,测定水质总磷的相对标准偏差为0．07％（n=5o对实际样品进行分析,总磷的加标回收率为94．5％～105．5％,表明该方法测定结果可靠,具有一定的应用价值。     

Simple and automatic determination of aldehydes and acetone in water by headspace solid-phase microextraction and gas chromatography-mass spectrometry

We describe a simple and automatic method to determine nine aldehydes and acetone simultaneously in water. This method is based on derivatization with 2,2,2-trifluoroethylhydrazine (TFEH) and consecutive headspace-solid-phase microextraction and gas chromatography-mass spectrometry. Acetone-d(6) was used as the internal standard. Aldehydes and acetone in water reacted for 30 min at 40°C with TFEH in a headspace vial and the formed TFEH derivatives were simultaneously vaporized and adsorbed on polydimethylsiloxane-divinylbenzene. Under the established condition, the method detection limit was 0.1-0.5 μg/L in 4 mL water and the relative standard deviation was less than 13% at concentrations of 0.25 and 0.05 mg/L. This method was applied to determine aldehydes and acetone in 5 mineral water and 114 surface water samples. All mineral water samples had detectable levels of methanal (24.0-61.8 μg/L), ethanal (57.7-110.9 μg/L), propanal (11.5-11.7 μg/L), butanal, pentanal (3.3-3.4 μg/L) and nonanal (0.3-0.4 μg/L). Methanal and ethanal were also detected in concentration range of 2.7-117.2 and 1.2-11.9 μg/L, respectively, in surface water of 114 monitoring sites in Korea.     

碲化镉纳米晶标记抗荧蒽抗体及其荧光免疫分析

以水热法合成的碲化镉(CdTe)纳米晶标记抗荧蒽抗体后,标记复合物的荧光强度增强,其分散性和稳定性良好。将此标记物用于直接竞争荧光免疫分析,测定了环境水样中荧蒽的含量。结果表明,在0.1～1000μg/L范围内有良好的线性关系;抑制率IC50为12.4μg/L,检出限IC20为13.1ng/L。对水样进行加标回收实验,回收率在95.1%～111%之间;相对标准偏差小于9%。本方法准确可靠,结果满意,能够满足环境中微量环境激素类污染物的检测需要。     

Determination of volatile chlorinated hydrocarbons in water samples by static headspace gas chromatography with electron capture detection

A simple, efficient, solvent‐free, and commercial readily available approach for determination of five volatile chlorinated hydrocarbons in water samples using the static headspace sampling and gas chromatography with electron capture detection has been described. The proposed static headspace sampling method was initially optimized and the optimum experimental conditions found were 10 mL water sample containing 20% w/v sodium chloride placed in a 20 mL vial and stirred at 50ºC for 20 min. The linearity of the method was in the range of 1.2–240 μg/L for dichloromethane, 0.2–40 μg/L for trichloromethane, 0.005–1 μg/L for perchloromethane, 0.025–5 μg/L for trichloroethylene, and 0.01–2 μg/L for perchloroethylene, with coefficients of determination ranging between 0.9979 and 0.9990. The limits of detection were in the low μg/L level, ranging between 0.001 and 0.3 μg/L. The relative recoveries of spiked five volatile chlorinated hydrocarbons with external calibration method at different concentration levels in pure, tap, sea water of Jiaojiang Estuary, and sea water of waters of Xiaomendao were in the range of 91–116, 96–105, 86–112, and 80–111%, respectively, and with relative standard deviations of 1.9–3.6, 2.3–3.5, 1.5–2.7, and 2.3–3.7% (n = 5), respectively. The performance of the proposed method was compared with traditional liquid–liquid extraction on the real water samples (i.e., pure, tap, and sea water, etc.) and comparable efficiencies were obtained. It is concluded that this method can be successfully applied for the determination of volatile chlorinated hydrocarbons in different water samples.     

Analysis of bromate in drinking water using liquid chromatography-tandem mass spectrometry without sample pretreatment

An analytical method for determining bromate in drinking water was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The (18)O-enriched bromate was used as an internal standard. The limit of quantification (LOQ) of bromate was 0.2 μg/L. The peak of bromate was separated from those of coexisting ions (i.e., chloride, nitrate and sulfate). The relative and absolute recoveries of bromate in two drinking water samples and in a synthesized ion solution (100 mg/L chloride, 10 mg N/L nitrate, and 100 mg/L sulfate) were 99-105 and 94-105%, respectively. Bromate concentrations in 11 drinking water samples determined by LC-MS/MS were <0.2-2.3 μg/L. The results of the present study indicated that the proposed method was suitable for determining bromate concentrations in drinking water without sample pretreatment.     

微波消解-紫外分光光度法测定水中总氮

研究了用微波消解-紫外分光光度法测定水样中的总氮,结果表明,所提出的消解方法具有操作简单、省时、消解完全的特点,精密度和准确度均令人满意．方法的线性范吲为0．0242～9．60mg／L,水样加标回收率为101％～103％,相对标准偏差为0．13％～0．44％。     

A New Spectrophotometry Method for the Determination of Aniline in Environmental Water Samples

ABSTRACT

A new spectrophotometric method has been established to determine trace aniline in water samples. A mixture solution of N-chlorosuccinimide and 8-hydroxyquinaldine in N, N-dimethylformamide (DMF) was used to react with the aniline in water at room temperature (20°C). When the solution was adjusted to pH 10-11 by adding 3 mol/L NaOH, a clear and blue-colored dye formed immediately with the maximum absorption wavelength at 615 nm. Molar absorptivity and detection limit were found to be 1.0×10⁴ L mol^?1 cm ^?1 and 30 μg/L, respectively. Linearity was excellent in the concentration range of 0.2 to 15 mg/L aniline in water sample. The proposed method has been used to analyze aniline in surface and sewage water samples with the recoveries 96-103% and relative standard deviation less than 3%. It's a promising method to be applied for routine analysis of aniline in water.     

Optimization of dispersive liquid-liquid microextraction and improvement of detection limit of methyl tert-butyl ether in water with the aid of chemometrics

Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry-selective ion monitoring (GC-MS-SIM) was applied to the determination of methyl tert-butyl ether (MTBE) in water samples. The effect of main parameters affecting the extraction efficiency was studied simultaneously. From selected parameters, volume of extraction solvent, volume of dispersive solvent, and salt concentration were optimized by means of experimental design. The statistical parameters of the derived model were R(2)=0.9987 and F=17.83. The optimal conditions were 42.0 μL for extraction solvent, 0.30 mL for disperser solvent and 5% (w/v) for sodium chloride. The calibration linear range was 0.001-370 μg L(-1). The improved detection limit with the aid of chemometrics was 0.3 ng L(-1). The relative standard deviation (RSD) with n=9 for 0.1 mg L(-1) MTBE in water with and without internal standard was 2.7% and 3.1%, respectively. Under the optimal conditions, the relative recoveries of spiked MTBE in different water samples were in the range of 100-105%.     

浊点萃取光度法测定水样中亚硝酸根

A new method for the determination of trace nitrite by spectrophotometric after cloud point extraction was proposed.The effects of experimental conditions such as acidity,concentration of chromogenic reagent and surfactant,equilibration temperature and time on cloud point extraction were discussed.Under the optimum conditions,a good linear relationship was obtained in the range of 4.0～200 μg/L of the nitrite(r=0.9998),the detection limits of 0.43 μg/L.The recoveries fell in the range from 97.7% to 102.4% an...     

Trace determination of dichlorvos in environmental samples by room temperature ionic liquid-based dispersive liquid-phase microextraction combined with HPLC

Using 1-butyl-3-methylimidazolium hexa?uorophosphate ([BMIM][PF6]) room temperature ionic liquid (RTIL) as extraction solvent, tetrahydrofuran (THF) as disperser solvent, the organophosphorus pesticide dichlorvos in water was determined by dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography. Factors affecting RTIL-DLLME (type of disperser solvent, amount of RTIL, volume of disperser solvent, percentage of NaCl and volume and pH of water sample) were optimized by the single-factor method, obtaining the most favorable results when using 65 μL of [BMIM][PF6] and 260 μL of THF to extract the compound from an 8-mL water sample at pH 5.0 containing 25% (w/v) of NaCl. Under these optimum conditions, an enrichment factor of 215-fold was obtained. The calibration curves were linear in the concentration range of 2-1,000 μg/L. The limit of detection calculated at a signal-to-noise ratio of 3 was 0.2 μg/L. The relative standard deviations (RSD) for six replicate experiments at 20, 100 and 200 μg/L concentration levels were 1.8%, 1.3% and 1.3 %, respectively. Then the proposed method was applied to the analysis of three different water sample sources (tap, farm and rain water) and the relative recoveries and RSD of spiked water samples were 95.6-102.4% and 0.6-3.1%, respectively, at three different concentration levels of 20, 100 and 200 μg/L.     

悬浮固化-分散液液微萃取-液相色谱-串联质谱测定纺织废水中磷系阻燃剂

建立了悬浮固化-分散液液微萃取结合液相色谱-串联质谱测定纺织废水中5种痕量磷系阻燃剂的方法。通过对萃取过程中萃取剂、分散剂的种类与体积、盐浓度、溶液pH值等对萃取效率的影响因素优化,确立了最佳萃取条件。采用了密度小于水的十一烷醇（400 μL）为萃取剂,甲醇（300 μL）为分散剂,控制溶液pH值在6~9之间,NaCl添加量为2 g,萃取时间为涡旋2 min。在优化的萃取条件下,该方法在2~100 μg/L均有良好的线性关系,相关系数大于0.995,除二（2,3-二溴丙基）磷酸酯（BIS）的检出限为5 μg/L外,三（2-氯乙基）磷酸酯（TCEP）、三（1,3-二氯-异丙基）磷酸酯（TDCP）、三（1-氮丙啶基）氧化膦（TEPA）和三（2,3-二溴丙基）磷酸酯（TRIS）的检出限均为2 μg/L。后整理、染色和印花等实际废水样品加标试验表明,方法的平均回收率为71.6%~114.5%,RSD为2.7%~11.2%（n=6）。对11个样品进行检测,其中3个废水样品检出TCEP与TDCP化合物,含量为2.6~3.4 μg/L。本方法简单,快速,灵敏度好且环保绿色,能够对纺织废水中的5种痕量磷系阻燃剂进行准确的定性与定量检测。