A nanosilver-based spectrophotometric method for determination of malachite green in surface water samples

A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate–acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0?×?10^?9–2.0?×?10^?7?mol?L^?1 malachite green with a correlation coefficient of 0.996. The limit of detection (S/N?=?3) was 2.0?×?10^?9?mol?L^?1. Relative standard deviation for ten replicate determinations of 1.0?×?10^?8?mol?L^?1 malachite green was 1.86 %. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.     

间接光度法测定水中硫酸根

介绍了用一定过量的氯化钡沉淀SO2-4,余下的Ba2+与加入一定过量的铬酸钾反应,存在于溶液中的铬酸根在pH3.4的HAc-NaAc介质中与联邻甲苯胺生成蓝绿色的产物,并且溶液的颜色随硫酸根的量呈线性关系,借此进行光度法测定硫酸根.本法选620nm为测定波长,硫酸根含量在0～125μg/10ml范围符合比尔定律.方法在用于测定自来水中硫酸根时,结果满意.     

火焰原子吸收法测定水中总铬

水中铬的测定有一定的技术难度。本文采用原子吸收测定方法,以铵盐作基体改进剂,可以有效地抑制铁与镍对水中铬的干扰。在仪器最佳工作条件下,对混合标准样进行了对比测定,获得了满意的测定结果     

钼酸铵分光光度法测定废水中的元素磷

利用钼酸铵分光光度法测定了水样中的元素磷,发现该方法的灵敏度、准确度和稳定性都可以满足分析的要求,并且用元素磷标准样品进行了对比实验,分析误差在10%以内.     

测定双酚A的流动注射化学发光法研究

在鲁米诺-高碘酸钾化学发光体系中加入双酚A,可以抑制该体系的化学发光,据此建立了双酚A的流动注射化学发光监测分析新方法。该法的线性范围为6 0×10-6～1 0×10-3g L,检测限为1 3×10-7g L。方法可用于水体中双酚A的测定。     

Turbidimetric determination of chloride in different types of water using a single sequential injection analysis system

A sequential injection analysis system for the turbidimetric determination of chloride in different types of water is proposed. The determination is based on the reaction of chloride with silver ions and the subsequent measurement of the turbidity caused by silver chloride precipitation. In this method, the use of toxic reagents, such as mercury thiocyanate, commonly employed in most spectrophotometric techniques for chloride determination, is avoided. The main feature of the developed system is the use of a single configuration to carry out the determination over a wide concentration range (2-400 mg L(-1)) by changing only the aspirated sample volume. This characteristic allows the determination of chloride in ground, surface and wastewaters using the same manifold. In addition, a considerable saving of precipitating reagent is achieved due to non-continuous consumption. The results obtained with the developed system were statistically indistinguishable from those of the potentiometric titration reference method. Relative standard deviations for ten consecutive injections were lower than 3.7%, with a sampling frequency of between 55 and 57 determinations per hour.     

Derivative spectrophotometric method for copper determination

A simple, sensitive and selective method by solvent extraction-first derivative spectrophotometry is described for the determination of microamounts of copper in water by means of its reaction and extraction at pH 8.0 with 3-(4-phenyl-2-pyridinyl-5-phenyl-1,2,4-triazine) (PPT) and picrate (2,4,6-trinitro-phenol) into 1,2-dichloroethane. Copper was thus determined in the range 7.5–350 ng/ml with a detection limits (3) of 2.3 ng/ml. The relative standard deviations were in all instances less than 2.0%. The proposed method was successfully applied for the determination of copper in several kinds of water.     

大辽河入海口水质在线自动监测系统取样工程的建设与维护

介绍一个以自吸喷射泵为取样泵的水质自动监测系统取样工程建设方案及其日常维护措施。适用于河口和四季分明水域建设水质自动监测站需要,更可在其他类型水域建站时借鉴使用。     

A new nanosilver-based spectrophotometric method for monitoring Eriochrome black T in river water

In this paper, a new spectrophotometric method is reported for the determination of nanomolar levels of Eriochrome black T in environmental samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of Eriochrome black T by hexacyanoferrate (III) in acetate–acetic acid medium and at 25 °C. The absorbance is measured at 512 nm with the fixed-time method. It relies on the linear relationship between the absorbance difference (?A) and Eriochrome black T amounts in the range of 40–1,250 nM. Under optimum conditions, the sensitivity of the proposed method, i.e., the detection limit corresponding to 80 s, is about 25 nM. The method is featured with good accuracy and reproducibility for Eriochrome black T determination in river water samples without any pre-concentration and separation step.     

地表水水质自动监测站提水系统最佳方案设计初探

介绍地表水水质自动监测站提水系统的设计方案 ,分析各方案的优缺点 ,探讨各方案的适应性及选择最佳方案 ,以期对自动站的建设提供参考。     

流动注射分光光度法测定废水中硫化物的研究

在硫化物的直接显色分光光度法 (GB/T1 71 3 3 -1 997)的基础上 ,对在线气体扩散 -流动注射分光光度测定废水中硫化物的管路参数等条件作了探讨。实验结果表明 ,硫化物的浓度在 0～ 1 0 mg/L范围内 ,具有良好线性关系。通过在线气体扩散分离技术 ,提高了分析速度 ,分析频率达 2 6次 /小时 ,方法的相对标准偏差在 3 .0 3 %～ 8.5 3 %之间 ,回收率在97.0 %～ 1 0 4.0 %之间。     

Sensitive spectrophotometric methods for the assessment of nitrite in water sample

Two spectrophotometric methods have been developed for the determination of nitrite using dapsone (DAP) with alpha-naphthol and 4-amino-5-hydroxynapthalene-2,7-disulphonic acid monosodium salt (AHNDMS) as chromogenic reagents with maximum absorbance wavelength at 540 and 520 nm respectively. For the method that utilizes dapsone with alpha-naphthol (DAP-alpha-naphthol), the beer's law range is obeyed between 0.05-0.8 microg ml(-1) with molar absorptivity of 5.749 x 104 l mol(-1) cm(-1). The second method that uses dapsone with AHNDMS (DAP-AHNDMS), the beer's law is valid over the range 0.2-1.4 mug ml(-1) and molar absorptivity 2.44 x 104 l mol(-1) cm(-1). The common interfering ions in the analytical procedures have been studied. This proposed methods are reliable, reproducible and have been successfully applied to determine nitrite in various water sources of environmental interest.     

An online preconcentration system for the determination of uranium in water and effluent samples

Amberlite XAD-4 resin functionalized with β-nitroso-α-naphthol was applied to an online system for the preconcentration and determination of uranium. U (VI) ions were retained on the minicolumn at an appropriate pH and then desorbed with acid solution. The amount of uranium in the eluate was measured spectrophotometrically at 650 nm using Arsenazo III as a colorimetric reagent. The limit of detection and the preconcentration factor were 1.8 μg L^???1 and 10, respectively. The chemical and flow variables affecting the preconcentration were studied. The influence of several ions on the system was also investigated. The method was successfully applied for the evaluation of uranium in water and in effluent samples.     

Flow injection spectrophotometric determination of methamidophos using online hydrolysis

A new protocol for the online spectrophotometric determination of methamidophos has been developed. The method is based on online hydrolysis of methamidophos, and the resulting hydrolyzed product is reacted with sodium nitroproside to form a colored complex. The calibration curve is linear over the concentration range of 0.5–20 μgml^?–?1, with a molar absorptivity of 2.5×10⁴ L mol^?1 cm^?1. The method is fast and reproducible with a sample throughput of 90 samples/h. The method is successfully applied to formulations and real samples.     

铋磷钼蓝分光光度法测定土壤中磷含量

土壤中磷含量的分析是土壤环境监测的主要项目之一.建立了铋磷钼蓝分光光度法测定土壤中磷含量的新方法,与现有的《土壤全磷测定方法》(GB 9837-88)和土壤总磷快速检测仪方法进行了比较讨论.方法的检出限为5.0 mg/kg,对磷含量为475 mg/kg和292 mg/kg的标准土壤样品进行测定,结果与标准值吻合,其相对...     

Validation of spectrophotometric method for Se(IV) determination: analytical applications

As selenium is an important part of the antioxidant enzymes and also because there are several studies suggesting a possible link between cancer and selenium deficiency, this paper presents a spectrophotometric method for the assay of Se(IV), using N,N-diethyl-p-phenylenediamine monohydrochloride as reagent. The proposed method is based on the reaction between the selenium and potassium iodide in low acidic medium, when iodine is released. This last product will further oxidise the new reagent. The final obtained product is strongly coloured in red and has an absorption maximum at 552 nm and molar extinction coefficient (ε) of 6.1?×?10⁴ L mol^?1 cm^?1. The optimum working conditions were established, and the developed method was validated, being characterised by a good linearity (in the range of 0.5–3.0 μg/mL), a limit of detection (0.0573 μg/mL) and a limit of quantification (0.1737 μg/mL). At the same time, the repeatability, the precision of the method and the accuracy were established. The proposed and validated method was applied with good results for the determination of Se(IV) in spring and bottled water from Iasi and also in pharmaceutical and cosmetic products.     

Dibenzazepin hydrochloride as a new spectrophotometric reagent for determination of hydrogen peroxide in plant extracts

A rapid, simple, accurate, and sensitive visible spectrophotometric method for the determination of trace amounts of hydrogen peroxide in acidic buffer medium is reported. The proposed method is based on the oxidative coupling of Ampyrone with dibenzazepin hydrochloride by hydrogen peroxide in the buffer medium of pH?4.0 which is catalyzed by ferrous iron. The blue-colored product formed with maximum absorption at 620?nm was found to be stable for 2?h. Beer's law is obeyed for hydrogen peroxide concentration in the range of 0.03-0.42?μg?ml(-1). The optimum reaction conditions and other important optical parameters are reported. The molar absorptive and Sandell's sensitivity are found to be 5.89?×?10(4)?mol(-1)?cm(-1) and 0.57?g/cm(2), respectively. The interference due to diverse ions and complexing agents was studied. The method is successfully applied to the determination of hydrogen peroxide in green plants satisfactorily.     

苯基荧光酮-溴代十六烷基三甲铵光度法测定微量镉的研究

研究了 Cd( ) 苯基荧光酮 CTMAB体系的分光光度测定 ,提出了一种测定镉的新方法。在 p H1 0 2的碳酸氢钠 氢氧化钠介质中 ,在 CTMAB存在下镉 ( )与苯基荧光酮形成红色配合物。其 λmax=578nm,ε578=2 .0× 1 0 4 L mol·cm,镉量在 0～ 1 2 5μg 2 5ml范围内遵守比耳定律。     

Simultaneous spectrophotometric determination of trace amount of polycyclic aromatic hydrocarbons in water samples after magnetic solid-phase extraction by using projection pursuit regression

Magnetic solid-phase extraction based on coated nano-magnets Fe₃O₄ was applied for the preconcentration of four polycyclic aromatic hydrocarbons (PAHs; anthracene, phenanthrene, fluorine, and pyrene) in environmental water samples prior to simultaneous spectrophotometric determination using multivariate calibration method. Magnetic nanoparticles, carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field so, no filtration or centrifugation was necessary. After elution of the adsorbed PAHs, the concentration of PAHs was determined spectrophotometrically with the aid of a new and efficient multivariate spectral analysis base on principal component analysis-projection pursuit regression, without separation of analytes. The obtained results revealed that using projection pursuit regression as a flexible modeling approach improves the predictive quality of the developed models compared with partial least squares and least squares support vector machine methods. The method was used to determine four PAHs in environmental water samples.