Spectrophotometric determination of titanium with N-m-Tolyl-N-phenylhydroxylamine and its application to environmental samples

N-m-Tolyl-n-phenylhydroxylamine is proposed for the spectrophotometric determination of titanium. The reagent forms a yellow chloroform-soluble complex with titanium in media with a hydrochloric acid concentration of at least 9M. The apparent molar absorptivity at 380 nm is 7.4 x 10(3) 1.mole(-1).cm(-1). The optimum final concentration range is 0-54 mug of titanium in 10 ml of chloroform. The complex contains the metal and reagent in 1:2 ratio. The proposed method has been successfully applied to the determination of titanium in coal, coal fly-ash, pond sediment and asphalt.     

Electrothermal atomic-absorption spectrometry of arsenic and its application to environmental samples

Electrothermal atomization of arsenic with a metal micro-tube atomizer has been studied. Thiourea and thionalide were found to give effective atomization of arsenic. A method involving extraction of the thionalide complex for determining traces of arsenic in water and soil is described.     

Investigation of the IC-ICP-MS determination of iodine species with reference to sample digestion procedures

The determination of iodine in aqueous solutions suffers from several serious problems, caused by the formation of iodine species, derived from the oxidative pretreatment of biological materials. For the determination of these iodine species an ion chromatograph was coupled with an ICP-mass spectrometer. Because of the possible interconversion of the iodine species depending on the pH-value, different eluent-column combinations were used for acidic or alkaline sample solutions, respectively. Iodide, iodate, and several not identified, presumably organo-iodine species could be separated and detected. Unfortunately, the iodine (I₂) itself could not be determined with the method proposed. The reaction products of pretreatment are influenced strongly by the matrix. Mixtures of different iodine containing components are received, dependent on the matrix composition and particularly on the pH-value.     

Determination of diphenylarsenic compounds related to abandoned chemical warfare agents in environmental samples

To elucidate the current extent of pollution of the environment with diphenylarsine chloride (DA, Clark I) and diphenylarsine cyanide (DC, Clark II), we have developed analytical procedures using gas and liquid chromatography and employed them to analyze water and soil samples. DA, DC, and their degradation products were extracted with water or organic solvents. Derivatization with n‐propanethiol was adopted to achieve higher analytical reproducibility. DA and DC were unstable and decomposed into bis(diphenylarsine)oxide (BDPAO) in water, but only negligibly into diphenylarsinic acid (DPAA) during the 30 days of a stability test. Diphenylarsenic compounds afforded the same product by this derivatization, but their reaction rates varied depending on the starting materials. DPAA had to be treated under acidic conditions at 60 °C to achieve the desired conversion efficiency. Recovery of the thiol derivatives of the diphenylarsenic compounds tested was almost quantitative from water, but only about 50% from soil, reflecting the low extraction efficiency. We applied the method to the analysis of organoarsenic compounds sampled from the water of the drinking well in Kamisu‐cho, Ibaraki Prefecture, where the water was thought to have had deleterious effects on the inhabitants. The high level of DPAA was identified as the causative agent. Our analyses of soil samples from Samukawa‐cho and Hiratsuka City, Kanagawa Prefecture, where a naval arsenal had previously stood, succeeded in identifying intact DA, BDPAO and triphenylarsine, diphenylarsenic thiol‐derivatives, as well as other substances (mustard gas, lewisite). The true magnitude of contamination became evident after these measurements. Copyright © 2005 John Wiley & Sons, Ltd.     

Trends in liquid-phase microextraction, and its application to environmental and biological samples

Liquid phase microextraction (LPME) is a popular technique for sample pretreatment before the trace determination of target compounds from complex matrices, examples being pesticides in environmental and food samples, or drug residuals in biological samples such as blood or urine. LPME is simple, affordable, easy to operate, and highly sensitive. It is a miniaturized implementation of conventional liquid-liquid extraction in which only a few microliters of solvents are used instead of several hundreds of milliliters. This review focuses on newly developed LPME-based techniques, their application to environmental and biological samples, on their limitations, and on future applications.

A study on proton induced X-ray analysis and its application to environmental samples

Proton induced X-ray analysis has been studied by the 5 MV Van de Graaff of Tohoku University emphasizing on backing materials and angular dependence of background. The method has further been applied to analyses of some environmental samples. From experimental results, it was found that 4 μm Mylar foil among Formvar, Mylar and carbon gives sufficiently low background spectrum, high sensitivity and good mechanical strength. The detection limit is much improved at the backward direction with respect to the incident beam comparing with that at 90° which has usually been adopted. The analytical results on soil and aerosol samples were compared with those by the Atomic Absorption Spectrophotometrical method (AAS). Vanadium can easily be analysed by this method, but not by the AAS method. Milk and human milk were also analysed.     

Determination of chemical warfare agents and related compounds in environmental samples by solid-phase microextraction with gas chromatography

Solid phase microextraction (SPME) is an increasingly common method of sample isolation and enhancement. SPME is a convenient and simple sample preparation technique for chromatographic analysis and a useful alternative to liquid-liquid extraction and solid phase extraction. SPME is speed and simply method, which has been widely used in environmental analysis because it is a rather safe method when dealing with highly toxic chemicals. A combination of SPME and gas chromatography (GC) permits both the qualitative and quantitative analysis of toxic industrial compounds, pesticides and chemical warfare agents (CWAs), including their degradation products, in air, water and soil samples. This work presents a combination of SPME and GC methods with various types of detectors in the analysis of CWAs and their degradation products in air, water, soil and other matrices. The combination of SPME and GC methods allows for low detection limits depending on the analyte, matrix and detection system. Commercially available fibers have been mainly used to extract CWAs in headspace analysis. However, attempts have been made to introduce new fiber coatings that are characterized by higher selectivities towards different analytes of interest. Environmental decomposition of CWAs leads to the formation of more hydrophilic products. These compounds may be isolated from samples using SPME and analyzed using GC however, they must often be derivatized first to produce good chromatography. In these cases, one must ensure that the SPME method also meets the same needs. Otherwise, it is helpful to use derivatization methods. SPME may also be used with fieldportable mass spectrometry (MS) and GC-MS instruments for chemical defense applications, including field sampling and analysis. SPME fibers can be taken into contaminated areas to directly sample air, headspaces above solutions, soils and water.     

Colorimetric technique for the detection of carbofuran and its application in various environmental samples

A large variety of pesticides have been used in the agriculture area to raise the quality, extend and yield storage life of crops. The nonstop uses of these pesticides have resulted in pollution of the environment and also caused risk to human health. For the rapid detection of selective CBFpesticide, we developed a simple and sensitive colorimetric detection method based on azo-coupling reaction. After a simple pre-treatment of carbofuran (2, 2-dimethyl-2, 3-dihydro-7-benzofuranyl N-methyl carbamate) (CBF) (1000 ​μg ​mL⁻¹) with a diazotized solution, the resulting is rapidly undergoing azo-coupling reaction with p-aminoantipyrine (1% alcoholic) with a dramatic color change only in few minutes. Finally, we successfully applied the concentrations of CBF pesticide on vegetable, fruit, soil, and water samples in the presence of natural interferences using UV–Vis spectrophotometer and FTIR with limits of detection at 0.004μgmL⁻¹. CBF had recoveries in the range of 93–98%, with relative standard deviation values less than 2% and good linearity was achieved with r ​≥ ​0.98. The inhibition rate was linear with CBF concentration in the range of 1μgmL⁻¹ to 10μgmL⁻¹. The proposed method applies to analyze CBF pesticide in real samples. FTIR technique was used to consider and gain structural information about the existing intermolecular interactions for vegetable samples.     

Determination of molybdenum in environmental samples

Molecular imprinted membrane of indole-3-ethanol (IE) was prepared by hybridization of IE imprinted polymer powder and polysulfone (PSf) membrane. The IE imprinted polymer by covalent imprinting method was synthesized with copolymerization of indole-3-ethyl methacrylate (IEMA) and divinylbenzene (DVB). The cross-linked P(IEMA-co-DVB) was ground to be powders having less than 63 μm size and then hybridized within PSf membrane by using phase inversion process. The resultant imprinted powder showed binding capacities of 1.8, 7.2, 0 and 0 μmol g⁻¹ for IE, indole, 8-hydroxyquinoline and pyrrole in aqueous solution, respectively, and after hybridization with the PSf membrane, the value was 46, 26, 0 and 0 μmol g⁻¹. As a result, it was found that the IE imprinted powder alone showed non-selectively binding to the IE, but, the hybridized powder within the PSf membrane bound selectively the IE. Evidence was presented that hydrophobic interaction of the PSf matrix caused the selective and efficient binding. We also showed separation behavior of the hybrid membranes and discussed on the binding selectivity of the IE molecule. In view point of hybrid effect of the PSf membrane and the cross-linked imprinted powder, the results of the separation of these substrates were considered.     

Determination of plutonium in environmental samples with quadrupole ICP-MS

A method for rapid determination of plutonium isotopes in environmental samples with ultrasonic nebulisation and quadrupole ICP-MS detection was established. Techniques for sample dissolution, pre-concentration and chemical separation were evaluated and the optimal scheme outlined. Comparisons with α-spectrometry and high resolution ICP-MS confirmed the suitability of the method when applied to different environmental matrices within the global fallout concentration range in the northern hemisphere as well as more contaminated sites. Operational detection limits were 0.5–1.5 fg/l for fresh waters and 0.03–0.1 ng/kg for lake sediments and saline marsh sediments.     

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

Summary Halides, particularly Br^- and Cl^-, have been used as indicators of potential sources of Na⁺ and Cl^- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na⁺ and Cl^- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression.     

Spectrophotometric determination of vanadium using variamine blue and its application to synthetic, environmental and biological samples

A simple, rapid and accurate spectrophotometric method is described for the determination of trace amounts of vanadium using variamine blue (VB) as a chromogenic reagent. The method is based on the oxidation of variamine blue to form a violetcolored species on reaction with vanadium(V), having an absorption maximum at 570 nm. Beer’s law is obeyed in the range of 0.1–2.0 μg ml^?1. The molar absorptivity and Sandell’s sensitivity were found to be 1.65 × 10⁴ l mol^?1 cm^?1 and 0.003 μg cm^?2, respectively. Optimum reaction conditions were evaluated in order to delimit the linear range. The effect of interfering ions on the determination is described. The proposed method has been successfully applied to the determination of vanadium in steel, pharmaceutical, environmental, and biological samples.     

Determination of thiourea and its organic derivatives with iodine trichloride

Thiourea and its organic derivatives and thiosemicarbazide are determined in water, methanol or glacial acetic acid medium by reaction with an excess of iodine trichloride in the presence of mercuric chloride. The reaction is complete in 15 min. The excess of iodine trichloride is evaluated by adding potassium iodide and titrating the liberated iodine with thiosulphate. A variety of organic thioureas can be determined with an average accuracy and precision of 0.2%.     

离子色谱-电感耦合等离子体质谱法测定植物性样品中的碘及其形态

建立了离子色谱-电感耦合等离子体质谱联用(IC-ICP/MS)测定植物性样品中碘及其形态的方法。采用碱提取法处理样品后,应用IC-ICP/MS检测植物样品中的碘离子和碘酸根;采用高温裂解法处理样品,使样品中各种形态的碘最终均转化为碘离子,然后应用IC-ICP/MS检测碘离子,从而实现总碘的测定。碘的方法检出限为0.010 mg/kg。碱提取法和高温裂解法处理样品的碘的加标回收率分别为89.6%～97.5%和95.2%～111.2%,结果令人满意。按照所建立的方法分别考察了紫菜、海带、圆白菜、茶叶、菠菜等常见植物性样品中碘的存在形式,结果表明,紫菜中的碘以有机碘为主,而海带、圆白菜、茶叶、菠菜中的碘则以无机碘为主。     

Determination of the total amount of organically bound chlorine,bromine and iodine in environmental samples by instrumental neutron activation analysis

The determination of chlorine, bromine and iodine present as non-polar, hydrophobic hydrocarbons in environmental samples is reported. The organohalogen compounds are separated from water into an organic phase by on-site liquid—liquid extraction, and from biological material by procedures based on lipid phase extraction and codistillation. After removal of inorganic halides by washing with water and concentration of the sample by evaporation of the solvent, the resulting extracts are analyzed for their chlorine, bromine and iodine contents by instrumental neutron activation analysis. Strict attention is paid to the possibility of contamination in every step of the procedure. Background values in routine analysis are approximately 100–200 ng of chlorine, <5 ng of bromine and <3 ng of iodine.     

Spectrophotometric determination of isoproturon using p-aminoacetophenone and its application in environmental and biological samples

A simple and sensitive method for the determination of isoproturon, a widely used herbicide is described here which is based on alkaline hydrolysis of isoproturon to its corresponding primary amine followed by diazotization and coupling with p-aminoacetophenone in alkaline medium. The absorption maxima of the coloured compound formed is measured at 525 nm. Beer's law is obeyed over the concentration range of 0.5-5.0 mug in a final solution volume of 25 ml (0.02-0.2 ppm). The molar absorptivity and Sandell's sensitivity were found to be 8.6x10(5) l mol(-1) cm(-1) and 0.0002 mug cm(-2), respectively. The method has been satisfactorily applied to the determination of isoproturon in environmental and biological samples.     

Determination of 210Pb in environmental samples

Summary Measurement of ²¹⁰Pb has gained a highly scientific attention due to its wide range of environmental applications. The most commonly used analytical techniques: gamma-spectrometry, beta-counting and alpha-spectrometry were used to measure environmental samples (geological, soil, sediment). Our paper is aiming at comparing the capabilities and limits of application of these three different analytical techniques for ²¹⁰Pb measurement in various environmental samples. In addition, analytical data of ²¹⁰Pb measurements with the three different techniques (gamma-spectrometry, beta-counting and alpha-spectrometry) are discussed to highlight the degree of comparability and the most probable sources of discrepancies and errors. Based on the demanded investigation, one analytical technique will be chosen for routine analysis, while the other techniques, if they are available, could be used for analytical quality assurance measures. It was essential to compare the analytical efficacy of each technique, which differ concerning the detection limit (MDA), sensitivity, analytical effort, the duration of analysis and waiting time before analysis.     

Determination of rare-earth elements in environmental samples

A procedure is suggested of extraction-chromatographic pre-separation of REE's for the next activation determination. This method was applied for analyzing geological samples, underground and surface water, some technological materials.     

Determination of vanadium species in environmental samples

The distribution of vanadium between different oxidation states plays an important role in its environmental chemistry. As its two most commons forms, vanadium(IV) and vanadium(V) have different toxicity, speciation analysis of this element is necessary for environmental and biological samples. This paper presents recent research on the determination of vanadium species. Some important problems concerning stability of vanadium forms and proposed separation techniques are discussed.