Electroanalytical and chromatographic determination of pentachlorophenol and related molecules in a contaminated soil: a real case example

Electroanalytical and chromatographic methodologies have been applied for the determination of pentachlorophenol (PCP) and some of its derivatives in real soil samples contaminated by industrial discharge. The analytes were extracted with hexane from soil samples collected at different points of the site and mixed to produce a representative sample. Square wave voltammetry (SWV) experiments were carried out on either a boron-doped diamond (BDD) electrode or a gold ultramicroelectrode (Au-UME) in an analyte composed by the Britton-Robinson (B-R) buffer at pH 5.5 with the direct addition of proper amounts of the extract. The voltammetric responses revealed an irreversible anodic peak at approximately 0.80 V vs. Ag/AgCl with a peak current showing a linear dependence on PCP concentration. This linear relationship yielded a detection limit (DL) of 2×10⁻⁸ mol l⁻¹ (or 5.5 μg l⁻¹) for the BDD electrode and 6.9×10⁻⁸ mol l⁻¹ (18.4 μg l⁻¹) for the Au-UME, while the independently measured HPLC detection limit was 1.1×10⁻⁸ mol l⁻¹ (3.0 μg l⁻¹). The application of electroanalytical and chromatographic methodologies in the analysis of soil extracts revealed, besides the PCP responses, signals for some related molecules such as o-tetrachlorobenzoquinone (o-chloranil), hexachlorobenzene and tetrachlorophenol. Recovering experiments for PCP showed a concentration of 27.5 mg kg⁻¹ for the electroanalytical determinations and 26.8 mg kg⁻¹ for the HPLC analysis, values exceedingly high if considering that the maximum residue limit established for natural waters by the Brazilian Environmental Agency is 10 μg l⁻¹.     

乙酰化气相色谱法快速测定皮革及皮革制品中的五氯苯酚残留量

在前人工作基础上，对皮革及皮革制品中五氯苯酚残留测定方法经试验改进，增加浓硫酸净化步骤，并以艾氏剂作为标物，乙酰五氯苯酚用填充气相色谱测定。     

Determination of pentachlorophenol residues in wine and corks by solvent extraction methodology and specific gas chromatography detection

Summary A gas chromatographic methodology with selective detection is presented for the analysis in wines and corks of pentachlorophenol residues, which are suspected to be the most likely precursors of some off-flavours described in several wine samples. After derivatisation, pentachlorophenol acetate residues were monitored by electrolytic conductivity detection and/or mass spectrometric detection in the selective ion mode at m/z 264 and 266. Recoveries varied from 80 to 96% for wine samples fortified with 5 to 100 g l^–1 and from 83 to 91% for corks (fortified at 25 to 100 g kg^–1). The proposed methodology allowed for a determination limit of g l^–1 for wine and 10 g kg^–1 for corks.     

环境样品中五氯苯酚分析方法的研究进展

本文概述了国内外环境样品中五氯苯酚(PCP)测定方法的研究状况,包括分光光度法、HPLC法、GC法和免疫分析法等。重点介绍了PCP的提取、衍生化过程,同时总结了各种方法的优缺点。引用文献19篇。     

Fe-Ni/TiO2纳米管阵列电极的制备、表征及光电催化还原五氯酚活性

采用阳极氧化法和浸渍电沉积联用法制备了不同负载量的Fe-Ni/TiO2纳米管阵列电极. 通过扫描电子显微镜(SEM)、 X射线光电子能谱(XPS)和电化学测量等手段对样品的微观形貌、 晶体结构和光电响应等特性进行分析. 考察了在0.6 V偏压下, 所制备的电极对五氯酚的光电催化还原性能. 结果表明, 适量的Fe和Ni纳米颗粒的负载, 降低了TiO2纳米管阵列光生电子-空穴对的复合几率; 浸渍电沉积5次的Fe-Ni/TiO2纳米管阵列电极光电催化还原降解五氯酚的效率为91.35%, 明显高于TiO2纳米管阵列电极.     

顶空固相微萃取-气相色谱法测定饮用水中氯酚

提出了应用气相色谱法与顶空固相微萃取样品预处理技术相结合的方法测定饮用水中2,4,6-三氯酚(TCP)和五氯酚(PCP)。选用20mL顶空瓶,其中预置0.1mol·L~(-1)盐酸溶液0.5mL及氯化钠4.0g,加入水样10.0mL,立即封盖。插入85μm聚丙烯酸酯萃取头,在500r·min~(-1)转速振荡条件下于60℃萃取40 min,随之进入色谱仪解吸并测定。测定中采用HP-5毛细管柱和程序升温(40℃～280℃)条件,并用载气流量为3mL·min~(-1)。测得2,4,6-TCP及PCP的线性范围依次为55μg·L~(-1)和12μg·L~(-1)以内,其检出限(3S/N)依次为0.15μg·L~(-1)和0.13μg·L~(-1),加入3个浓度水平的标准溶液对方法的回收率及精密度作了试验,测得回收率在90.0%～112.8%之间,相对标准偏差(n=6)在3.0%～4.9%之间。     

Accurate analysis of trace pentachlorophenol in textiles by isotope dilution liquid chromatography-mass spectrometry

A highly accurate method for measuring pentachlorophenol (PCP) concentrations in textile samples was developed. This highly accurate method for the analysis of textile samples is valuable, given the inherent challenges associated with the complexity of the sample matrix. This method can be applied to certify the concentration of pentachlorophenol in textile CRMs. A measurement procedure based on isotope dilution liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) was developed. Samples were pretreated with acid and then with n-hexane. Excellent precision was obtained. The validated concentration ranges for the method were 1.0-50 ng/g, the LOD was 1.0 ng/g, and the LOQ was 5.0 ng/g. The precision of this method is in the range of 0.80-1.40%. The method can trace to mass.     

Application of persulfate with hydrodynamic cavitation and ferrous in the decomposition of pentachlorophenol

Hydrodynamic cavitation (HC) and Fe(II) are advanced oxidation processes, in which pentachlorophenol (PCP) is treated by the redox method of activating persulfate (PS). The kinetics and mechanism of the HC and Fe(II) activation of PS were examined in aqueous solution using an electron spin resonance (ESR) spin trapping technique and radical trapping with pure compounds. The optimum ratio of Fe(II)/PS was 1:2, and the hydroxyl radical (HO) and sulfate radical (SO₄⁻) generation rate were 5.56 mM h⁻¹ and 8.62 μM h⁻¹, respectively. The generation rate and R_ct of HO and SO₄⁻ at pH 3 and 50 °C in the Fe(II)/PS/HC system are 7584.6 μM h⁻¹, 0.013 and 24.02 μM h⁻¹, 3.95, respectively. The number of radicals was reduced as the pH increased, and it increased with increasing temperature. The PCP reaction rate constants was 4.39 × 10⁻² min⁻¹ at pH 3 and 50 °C. The activation energy was 10.68 kJ mol⁻¹. In addition, the mechanism of PCP treatment in the Fe(II)/PS/HC system was a redox reaction, and the HO⁻/SO₄⁻ contribution was 81.1 and 18.9%, respectively. In this study, we first examined PCP oxidation through HO and SO₄⁻ quantification using only the Fe(II)/PS/HC process. Furthermore, the results provide the foundation for activation of PS by HC and Fe(II), but also provide a data basis for similar organic treatments other than PCP.     

Immobilization of laccase by Cu2+ chelate affinity interaction on surface modified magnetic silica particles and its use for the removal of pentachlorophenol

Magnetic Cu²⁺-chelated silica particles using polyacrylamide as a metal-chelating ligand was developed and used for the immobilization of laccase by coordination.The effect of pH and temperature on the enzymatic property of immobilized laccase and its catalytic capacity for pentachlorophenol（PCP） degradation were evaluated systemically.Compared with free laccase,the immobilized laccase showed improved acid adaptabihty and thermal stability.The immobilized laccase prepared in this work exhibited a good catalytic capacity for PCP removal from aqueous solutions.     

Controlling the Fenton Reaction for Soil Remediation

ABSTRACT

This paper describes the use elemental iron to control the Fenton reaction, a process in which ferrous ion reacts with hydrogen peroxide. It is widely believed that the Fenton reaction produces free radicals that can degrade organic chemicals. By using elemental iron in place of ferrous iron, we found that the vigor of the Fenton reaction can be controlled, and therefore can be used more effectively to remediate contaminated soil.

Laboratory studies were done to compare the elemental iron approach with the original ferrous salt approach. It was found that elemental iron can increase the effectiveness of the Fenton reaction in degrading organic chemical such as Pentachlorophenol (PCP). The mechanism of control lies in the production of ferrous irons from elemental iron in the presence of hydrogen peroxide.