Pre-concentration and determination of fluorescence quenching of CdS quantum dots of Pb ions by dispersive liquid–liquid microextraction in the presence of the ionic liquids

2018 ◽  
Vol 47 (2) ◽  
pp. 127-132
Author(s):  
Ehsan Jafarnejad ◽  
Jafar Abolhasani ◽  
Arezoo Derakhshan
Keyword(s):  
Quantum Dots ◽  
Ionic Liquids ◽  
Fluorescence Quenching ◽  
Cadmium Sulphide ◽  
Content Type ◽  
Relative Standard ◽  
Pb Ions ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

Purpose This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry. Design/methodology/approach Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots. Findings Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained. Originality/value This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.

Dispersive Liquid-Liquid Microextraction Based on Ionic Liquid and Spectrophotometric Determination of Bilirubin in Biological Samples

2020 ◽  
Vol 16 (5) ◽  
pp. 652-659
Author(s):  
Asiye A. Avan ◽  
Hayati Filik
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Biological Samples ◽  
Urine Samples ◽  
Spectrophotometric Detection ◽  
Full Color ◽  
Dispersive Liquid Liquid Microextraction ◽  
Urine And Serum ◽  
Liquid Microextraction

Background: An Ionic Liquid-based based Dispersive Liquid-Liquid Microextraction (IL-DLLME) method was not applied to preconcentration and determination of bilirubin. Ionic Liquids (ILs) are new chemical compounds. In recent years, Ionic Liquids (ILs) have been employed as alternative solvents to toxic organic solvents. Due to these perfect properties, ILs have already been applied in many analytical extraction processes, presenting high extraction yield and selectivity for analytes. Methods: In this study, IL-DLLME was applied to biological samples (urine and serum) for the spectrophotometric detection of bilirubin. For bilirubin analysis, the full-color development was based on the reaction with periodate in the presence of hydrochloric acid. The high affinity of bilirubin for the ionic liquid phase gave extraction percentages above 98% in 0.3 M HCl solution. Results: Several IL-extraction parameters were optimized and room temperature ionic liquid 1-butyl- 1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and ethanol were used as extraction and disperser solution. The linear range was found in the range of 0.5-6.0 μM (0.3-3.5 μg mL-1) and the limits of detection of the proposed method was 0.5 μM (0.3 μg mL-1). The proposed method was applied for the preconcentration and separation of trace bilirubin in real urine samples. Also, the recoveries for bilirubin in spiked biological samples (urine and serum) were found to be acceptable, between 95-102%. Conclusion: The proposed IL-DLLMEapproach was employed for the enrichment and determination of trace levels of bilirubin in urine samples using NaIO4 as an oxidizing agent and Uv-vis spectrophotometric detection. The periodate oxidation of bilirubin is rapid, effective, selective, and simple to perform. The method contains only HCl, NaOI4, and an anionic surfactant. The method may be useful for economizing in the consumption of reagents in bilirubin determining. The IL-DLLMEmethod ensures a high yield and has a low toxicity no skin sensitization, no mutagenicity and no ecotoxicity in an aquatic environment since only very low quantities of an IL is required. For full-color formation, no any extra auxiliary reagents are required. Besides, the IL-DLLME technique uses a low-cost instrument such as Uv-vis which is present in most of the medical laboratories.

Simultaneous Determination of Four Plant Hormones in Soil by Ultrasound-Assisted Ionic Liquid Based Dispersive Liquid-Liquid Microextraction

2014 ◽  
Vol 675-677 ◽  
pp. 181-184 ◽  
Author(s):  
Gui Qi Huang ◽  
She Ying Dong ◽  
Zhen Yang ◽  
Ting Lin Huang
Keyword(s):  
Ionic Liquid ◽  
Plant Hormones ◽  
High Performance ◽  
Extraction Solvent ◽  
Target Analytes ◽  
Relative Standard ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

An ultrasound-assisted ionic liquid based dispersive liquid-liquid microextraction (UA-IL-DLLME) was developed for the determination of four plant hormones (6-benzyladenine (6-BA), kinetin (6-KT), 2, 4-dichlorophenoxy acetic acid (2, 4-D) and uniconazole (UN)) in soil, using high performance liquid chromatography (HPLC)-diode array detection (DAD). Several important parameters including the type and volume of extraction solvent, the volume of disperser solvent, ultrasound time, pH of the solution and salt effect were studied and optimized. Under optimum conditions, the limits of detections (LODs) for the target analytes were in the range of 0.002-0.01 μg g-1. And satisfactory recoveries of the target analytes in the soil samples were 79.3-96.7 %, with relative standard deviations (RSD, n=5) that ranged from 4.3 to 6.7%.

scholarly journals Use of Dispersive Liquid-Liquid Microextraction and UV-Vis Spectrophotometry for the Determination of Cadmium in Water Samples

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
J. Pérez-Outeiral ◽  
E. Millán ◽  
R. Garcia-Arrona
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Experimental Conditions ◽  
Cadmium Determination ◽  
A Value ◽  
Relative Standard ◽  
Potential Applicability ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

A simple and inexpensive method for cadmium determination in water using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry was developed. In order to obtain the best experimental conditions, experimental design was applied. Calibration was made in the range of 10–100 μg/L, obtaining good linearity (R2 = 0.9947). The obtained limit of detection based on calibration curve was 8.5 μg/L. Intra- and interday repeatability were checked at two levels, obtaining relative standard deviation values from 9.0 to 13.3%. The enrichment factor had a value of 73. Metal interferences were also checked and tolerable limits were evaluated. Finally, the method was applied to cadmium determination in real spiked water samples. Therefore, the method showed potential applicability for cadmium determination in highly contaminated liquid samples.

Vortex-Assisted Dispersive Liquid–Liquid Microextraction Coupled with Deproteinization for Determination of Nateglinide in Human Plasma Using HPLC/UV

2020 ◽  
Author(s):  
Mohamed A Hammad ◽  
Amira H Kamal ◽  
Reham E Kannouma ◽  
Fotouh R Mansour
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Limit Of Detection ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
Salt Addition ◽  
Relative Standard ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

Abstract A validated method for preconcentration and determination of nateglinide in plasma was developed using vortex-assisted dispersive liquid–liquid microextraction. Different variables that affect extraction efficiency were studied and optimized, including type and volume of extractant, type and volume of disperser, pH of diluent, salt addition effect, centrifugation and vortex time. Nateglinide was extracted using 30 μL of 1-octanol as an extractant and 200 μL of methanol as a disperser. The enrichment factor reached 330 under the optimum conditions. High-performance liquid chromatography/ultraviolet was used for detection using phosphate buffer (pH 2.5, 10 mM): acetonitrile (45:55, v/v) as a mobile phase at a flow rate of 1 mL/min. The method was linear over the range of 50–20,000 ng/mL with a limit of detection of 15 ng/mL (signal-to-noise ratio = 3). Intra- and inter-day precision had %relative standard deviation <6% (n = 3) and the %recoveries were found to be between 102.5 and 105.9%. The proposed method is simple, sensitive, eco-friendly, cost-effective and powerful for microextraction of nateglinide from human plasma samples.

Chitosan–Zinc Oxide Nanoparticles Combined with Dispersive Liquid–Liquid Microextraction for the Determination of BTEX in Water Samples

2015 ◽  
Vol 68 (3) ◽  
pp. 481 ◽  
Author(s):  
Mostafa Khajeh ◽  
Leyla Azarsa ◽  
Mansoureh Rakhshanipour
Keyword(s):  
Zinc Oxide ◽  
Water Samples ◽  
Zinc Oxide Nanoparticles ◽  
Solid Phase ◽  
Oxide Nanoparticles ◽  
Flame Ionization ◽  
Relative Standard ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

In this study, chitosan–zinc oxide nanoparticles were used as an adsorbent matrix for solid-phase extraction and combined with dispersive liquid–liquid microextraction (SPE–DLLME) for determination of benzene, toluene, ethylbenzene, and xylene isomers (BTEX) in water samples. The eluent of SPE was used as the dispersive solvent of the DLLME for further purification and enrichment of the BTEX prior to gas chromatography-flame ionization detector analysis. The effect of variables, including amount of adsorbent, sample and eluent flow rate, type and volume of extraction and dispersive solvent, salt concentration, and extraction time, was investigated and they were optimized. Under the optimum conditions, good linearity for all BTEX with determination coefficients in the range of 0.9993 < r2 < 0.9997, suitable precision (1.4 % < RSD <1.9 %; where RSD refers to relative standard deviation), and low detection limits (0.5–1.1 µg L–1) were achieved. The current chitosan–zinc oxide nanoparticles SPE–DLLME procedure combines the advantages of SPE and DLLME, and was applied for determination of BTEX in water samples and acceptable recoveries were obtained.

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