Deltamethrin Residues in Milk and Cheese of Lactating Goats (Capra hircus)

peer-reviewedThe distribution of pyrethroid insecticide deltamethrin (DLM) in goat milk and cheese (caciotta) following pour-on administration at the sheep dosage (DLMS-10 mL/60 kg body weight) and double dosage (DLMD-20 mL/60 kg body weight) was studied. DLM concentrations were measured in milk collected from study animals (No.14) before treatment and at 2, 4, 8, 12, 16, 24, 30, 36, 48, 56, until 168 h (7 days) post treatment and in caciotta cheese at 12 and 24 h post treatment. At both dosages, the maximum level of DLM residues in goat milk and cheese was below the maximum residue limit (MRL) of 20 μg kg−1 established for bovine milk (EU No 37/2010) at all time points. However, in terms of public health, higher DLM residues in cheese show that further specific studies should be performed on double dosage efficacy and pharmacokinetic and pharmacodynamics properties of ectoparasites in lactating goats

Application of green sample preparation techniques for the rapid analysis of aqueous samples by high performance liquid chromatography

近年來隨著科技的進步，分析儀器已具備高靈敏度的優點，但是大部分的儀器還難以直接測定諸如生物、食物以及環境等複雜基質的樣品。因此樣品前處理技術仍為化學分析過程一項極為重要的課題。將分析測定物有效地從複雜基質中分離，對分析結果的準確度與可信度有極大的影響。由於快速、低成本、以及綠色環境友善的要求，小型化的樣品前處理技術的發展應運而生。本論文將介紹低密度溶劑超音波輔助乳化微萃取(LDS-USAEME) 技術，此技術僅用數微升的萃取溶 劑能快速萃取多種分析物。本論文 著 重 於 開發三種新型低密度溶劑超音波輔助乳化微萃取技術，應用在環境、生物、和食品中的樣品分析。 首先開發超音波輔助乳化微萃取暨漂浮凝固化有機液滴(USAEME-SFO) 技術 結合 高 效液相層析儀紫外光偵測 (HPLC-UV) 為一個具快速、 有效及高靈敏 偵測 環 境 水 樣 中 氯苯胺的方法。經詳細研究影響萃取效率之參數及建立最佳萃取條件，10毫升水樣品在 pH 為11時以 60 μL 的1-dodecanol 當萃取溶劑在2分鐘的超 音波震盪 下進行萃取 可 獲 得 最佳萃取效果。在最佳化的條件下，檢量線之線性偵測範圍為0.05-500 μg L-1， 其 相 關 係數介於0.9948~0.9957之間。所測定氯苯胺化合物的方法偵測極限(LOD) 可低至0.01 μg L-1與0.1 μg L-1之間，相對標 準偏差(RSD)為 在2.1%到6.1%之間 。 本 方 法 成 功 地 應 用在真實環境水樣氯苯胺化合物的分析，其相對回收率介在81.1 %到116.0 % 之 間。 其次，生物樣品的分析常涉及複雜基質且微量問題，因此對於樣品的淨化是生物樣品分析最嚴苛的過程。在本論文研究中，利用LDS-USAEME方法結合HPLC-UV 開 發 為 人 體尿液中吲達帕胺噻嗪類利尿劑的分析技術。經詳細研究影響萃取效率之參數及建立最佳萃取條件後，在最佳化條件下，尿液中吲達帕胺校正檢量線之線性偵測範圍為1 - 100 μg L-1，其相關係數為0.9977。LOD為0.3 μg L-1及RSD值為1.2 - 6.6 % 。 應 用 本 方 法 於 真實樣品後可獲得相對回收率介於80-119 %。本技術開 發 提 供 了 一 個 快 速 、 低 成 本 、和具方便性偵測人類尿液樣品中的吲達帕胺的方法。 第三，食品分析在食品安全及品質控制上佔重要的角色，在本論文研究中，利用LDSUSAEME開發為偵測多數水果中常見的噻菌靈(TBZ)殺菌劑的前處理方法，配合液相層析儀-紫外光偵測 器對果汁樣品中的TBZ作測 定。經詳細研究影響萃取效率之 參數及 建 立 最佳萃取條件後，在最佳化條件下，TBZ校正檢量線之線性偵測範圍為0.75-100 μg L-1 ， 其相關係數為0.9981。LOD為0.1μg L-1及RSD值為1.1-7.9 %。本方 法被 應用 在偵 測 真 實的果汁樣品中的TBZ獲得相對回收率96-107 %。 以上的結果顯示出本方法有著非常廣泛的應用，而且本方法是簡單、可靠、有效、且對環境友善，從而證明出此方法可作為一個簡單且綠色方法去檢測環境、生物、食品水樣中的分析物。In recent years, sensitivity of analytical instruments has been achieved, but most of them cannot directly handle the complex matrices such as biological, food and environmental samples yet. Sample preparation is important for isolating desired components of interest from complex matrices and greatly influences their accurate and reliable analysis. The increasing demand for faster, inexpensive, and more environment-friendly methods has favored the miniaturization of sample preparation techniques. One extraction technique recently introduced is low density solvent based-ultrasound assisted emulsification microextraction (LDS-USAEME) technique which enables rapid extraction of various analytes with few microliters of extraction solvent. This dissertation focuses on the development of three novel applications of the LDS-USAEME technique to aqueous sample analysis, which includes environmental, biological and food aqueous samples. Firstly, a rapid, efficient and sensitive method for the determination of chlorinated anilines in environmental water samples has been developed using ultrasound assisted emulsification microextraction followed by solidification of floating organic droplet (USAEME-SFO) technique coupled with high performance liquid chromatography ultraviolet (HPLC-UV) detection. Parameters influencing the extraction efficiency were thoroughly investigated and the optimum extraction conditions were established which includes analysis of 10mL aqueous sample at pH 11 and 60 μL of 1-dodecanol as the extraction solvent under 2 min of ultrasonication. Under optimal conditions, linear range of calibration plots ranged from 0.05-500 μg L-1 with correlation coefficients ranging from 0.9948 to 0.9957. Limit of detection (LOD) of the proposed method ranged from 0.01 to 0.1 μg L-1 and the relative standard deviations (RSDs) varied from 2.1 to 6.1%. The proposed method has also been successfully applied to analyze real water samples and the relative recoveries of environmental water samples ranged from 81.1 to 116.9%. Secondly, biological samples usually involve complex matrices, and in many applications, sample cleanup is the most demanding procedure. In this work, indapamide, an important pharmaceutical drug which belongs to the class of thiazide-type diuretics, was determined in human urine by the application of LDS-USAEME method coupled with HPLC-VWD. Under optimal conditions, calibration was linear in the concentration range from 1-100 μg L-1 with a correlation coefficient of 0.9977 for the target analyte. The LOD was 0.3 μg L-1 and the RSDs varied from 1.2-6.6%. Relative recoveries in real samples were ranged from 80-119%. The proposed method provided a rapid, sensitive, low cost, easy to handle, and convenient alternative to determine indapamide in human urine samples. Thirdly, food analysis is crucial for food safety and quality control and in this work, thiabendazole (TBZ), a commonly used fungicide in various fruits has been determined in commercial fruit juice samples by the LDS-USAEME procedure coupled with HPLC-VWD detection. Optimum conditions of extraction were investigated and established. Under optimal conditions, linear range of calibration plots ranged from 0.75-100 μg L-1 and RSDs ranged from 1.1-7.9% with a correlation coefficient of 0.9981 for TBZ and the LOD obtained was 0.1 μg L-1. The proposed method was applied to the determination of TBZ in real fruit juice samples and the relative recoveries obtained ranged from 96-107%. The above results indicated that the proposed method had very wide applicability and was simple, reliable, efficient and environment-friendly, thereby proving to serve as a simple and green sample preparation method for the rapid determination of target analytes in environmental, biological and food aqueous samples.Table of contents ACKNOWLEDGEMENTS…………………………………………………………………......ii ABSTRACT-CHINESE………………………………………………………………………...iii ABSTRACT-ENGLISH…………………………………………………………………………v TABLE OF CONTENTS……………………………………………………………………..viii LIST OF FIGURES AND TABLES………………………………………………………......xii ABBREVIATIONS………………………………………………………………………….....xv CHAPTER-I GENERAL INTRODUCTION………………………………………………….1 1.1 Analytical process ……………………………………………………………………….......2 1.1.1 Sampling…………………………………………………………………………………..3 1.1.2 Sample Preparation………………………………………………………………………..3 1.1.3 Chromatographic Separation……………………………………………………………...4 1.1.3.4 High performance liquid chromatography…………………………………………….4 1.2 Overview of extraction techniques for aqueous samples………………………………….5 1.2.1 Liquid-liquid extraction……………………………………………………………………6 1.2.2 Solid phase extraction………………………………………………………………...……7 1.3 Green analytical chemistry…………………………………………………………………..7 1.3.1 Green sample preparation…………………………………………………………………..8 1.4 Historical development of microextraction techniques…………………………………….9 1.4.1 Solvent based microextraction techniques…………………………………………………10 1.4.1.1 Single drop microextraction (SDME)………………………………………………...10 1.4.1.2 Hollow fiber liquid phase microextraction (HF-LPME)……………………………..12 1.4.1.3 Liquid phase microextraction-solidification of floating organic droplet ……………13 1.4.1.4 Dispersive liquid-liquid microextraction……………………………………………..13 1.5 Ultrasound energy- a clean and green energy approach………………………………....15 1.5.1 Acoustic cavitations………………………………………………………………………18 1.5.2 Trends in ultrasound assisted sample preparations……………………………………….20 1.5.3 Ultrasound assisted emulsification microextraction (USAEME)………………………...21 1.6 Analysis of Aqueous samples………………………………………………………………22 1.6.1 Environmental aqueous samples………………………………………………………….24 1.6.2 Biological aqueous samples………………………………………………………………25 1.6.3 Food aqueous samples……………………………………………………………………26 1.7 Objective of this study……………………………………………………………………….27 CHAPTER-II RAPID ANALYSIS OF CHLORINATED ANILINES IN ENVIRONMENTAL WATER SAMPLES USING USAEME-SFO-HPLC-UV…………...30 2.1 Brief Introduction…………………………………………………………………………..31 2.1.1 Review of sample preparation methods for CAs………………………………………....33 2.1.2 Aim of the present study………………………………………………………………….35 2.2 Experimental………………………………………………………………………………..36 2.2.1 Reagents and solutions……………………………………………………………………36 2.2.2 Instrumentation…………………………………………………………………………...37 2.2.3 USAEME-SFO Procedure………………………………………………………………..37 2.3 Results and discussion……………………………………………………………………...38 2.3.1 Selection of extraction solvent……………………………………………………………38 2.3.2 Effect of volume of extraction solvent……………………………………………………39 2.3.3 Effect of ultrasonication time……………………………………………………………..40 2.3.4 Effect of sample pH……………………………………………………………………....41 2.3.5 Effect of ionic strength……………………………………………………………………43 2.3.6 Evaluation of method performance…………………………………………………….....45 2.3.7 Application to environmental water samples……………………………………………..46 2.3.8 Comparison of USAEME-SFO with other methods……………………………………...48 2.4 Summary…………………………………………………………………………………….49 CHAPTER-III RAPID DETERMINATION OF INDAPAMIDE IN HUMAN URINE USING NOVEL LDS-USAEME-HPLC-VWD……………………………………………….51 3.1 Brief Introduction………………………………………………………………………….....52 3.1.1 Literature background for indapamide analysis………………………………………......53 3.1.2 Aim of the present study……………………………………………………………….…54 3.2 Experimental…………………………………………………………………………………55 3.2.1 Reagents and solutions…………………………………………………………………...55 3.2.2 Urine sampling……………………………………………………………………………56 3.2.3 Instrumentation…………………………………………………………………………...56 3.2.4 LDS-USAEME Procedure……………………………………………………………......57 3.3 Results and discussion……………………………………………………………………….58 3.3.1 Selection of extraction solvent……………………………………………………………58 3.3.2 Effect of extraction solvent volume………………………………………………………58 3.3.3 Effect of ultrasonication time…………………………………………………………......60 3.3.4 Effect of sample pH………………………………………………………………………61 3.3.5 Effect of ionic strength……………………………………………………………………62 3.3.6 Evaluation of quantitative aspects…………………………………………………..........63 3.3.7 Application of the method………………………………………………………………..64 3.3.8 Comparison of the present technique with other reported methods………………...........66 3.4 Summary……………………………………………………………………………………..67 CHAPTER-IV RAPID DETERMINATION OF THIABENDAZOLE IN CITRUS FRUIT JUICES BY LDS-USAEME-HPLC-VWD……………………………………………………68 4.1 Brief Introduction…………………………………………………………………………….69 4.1.1 Aim of the present study……………………………………………………………….....72 4.2 Experimental…………………………………………………………………………………72 4.2.1 Reagents and solutions……………………………………………………………………72 4.2.2 Instrumentation…………………………………………………………………………...73 4.2.3 LDS-USAEME Procedure………………………………………………………………..74 4.2.4 Fruit juice sampling………………………………………………………………………74 4.3 Results and discussion……………………………………………………………………….74 4.3.1 Selection of extraction solvent……………………………………………………………75 4.3.2 Effect of extraction solvent volume……………………………………………................76 4.3.3 Effect of extraction time…………………………………………………...……………..77 4.3.4 Effect of sample pH………………………………………………………………….......78 4.3.5 Effect of ionic strength……………………………………………………………………79 4.3.6 Evaluation of quantitative aspects………………………………………………..............81 4.3.7 Application of the method to real samples…………………………………………….....82 4.3.8 Comparison of present method with other reported techniques……………………….....83 4.4 Summary……………………………………………………………………………………..84 CHAPTER-V CONCLUSIONS………………………………………………...........………..85 References……………………………………………………………………………………...88 List of Publications……………………………………………………………………………10

Rapid analysis of chlorinated anilines in environmental water samples using ultrasound assisted emulsification microextraction with solidification of floating organic droplet followed by HPLC-UV detection

The present study demonstrates a simple, rapid and efficient method for the determination of chlorinated anilines (CAs) in environmental water samples using ultrasonication assisted emulsification microextraction technique based on solidification of floating organic droplet (USAEME-SFO) coupled with high performance liquid chromatography-ultraviolet (HPLC-UV) detection. In this extraction method, 1-dodecanol was used as extraction solvent which is of lower density than water, low toxicity, low volatility, and low melting point (24 °C). After the USAEME, extraction solvent could be collected easily by keeping the extraction tube in ice bath for 2 min and the solidified organic droplet was scooped out using a spatula and transferred to another glass vial and allowed to thaw. Then, 10 μL of extraction solvent was diluted with mobile phase (1:1) and taken for HPLC-UV analysis. Parameters influencing the extraction efficiency, such as the kind and volume of extraction solvent, volume of sample, ultrasonication time, pH and salt concentration were thoroughly examined and optimized. Under the optimal conditions, the method showed good linearity in the concentration range of 0.05–500 ng mL−1 with correlation coefficients ranging from 0.9948 to 0.9957 for the three target CAs. The limit of detection based on signal to noise ratio of 3 ranged from 0.01 to 0.1 ng mL−1. The relative standard deviations (RSDs) varied from 2.1 to 6.1% (n=3) and the enrichment factors ranged from 44 to 124. The proposed method has also been successfully applied to analyze real water samples and the relative recoveries of environmental water samples ranged from 81.1 to 116.9%

Microwave assisted headspace controlled-temperature single drop microextraction for liquid chromatographic determination of chlorophenols in aqueous samples

We report on an efficient one-step sample preconcentration technique by coupling microwave heating and cloud vapor zone (CVZ)-based headspace controlledtemperature single drop microextraction (HS-CT-SDME), and its application to headspace extraction of chlorophenols in aqueous solutions. Microwave irradiation is utilized to accelerate evaporation of analytes into the headspace sampling zone for the direct extraction of aqueous chlorophenols. A microdrop of extractant is suspended at the bottom of a bell-mouthed micropipette tip connected to a microsyringe needle. An external cooling system was adopted to control the formation of the CVZ around the SDME tip in the headspace sampling area. In the CVZ procedure, the warm headspace vapor is quickly cooled near the SDME tip, thus forming a dense cloud of analyte-water vapor; thereby enhancing the partition of the analytes into the SDME solvent. The chlorophenols are then determined by LC-UV detection. Under the optimized experimental conditions, the analytical signal is linearly related to the concentration of the chlorophenols range of 2.5–250 ng mL−1. The detection limits vary from 0.3 to 0.7 ng mL−1, and the precision (expressed as the relative standard deviation) from 3.7 to 13.3 %. The method was validated with real water samples, and the spiked recovery ranged between 92 and 103.1 % for river water, and between 85.1 % and 98.6 % for lake water. Compared to other methods, microwave assisted HS-CT-SDME is simple, rapid, sensitive, inexpensive and eco-friendly, and requires less sample and organic extractant