Ultrasound-Assisted Emulsification Microextraction in an Online System for Determination of Cadmium in Water and Tea Samples

2018 ◽  
Vol 101 (5) ◽  
pp. 1647-1652 ◽  
Author(s):  
Leane Santos Nunes ◽  
Valfredo Azevedo Lemos
Keyword(s):  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Limit Of Quantification ◽  
Online System ◽  
Extraction Solvent ◽  
Flame Atomic Absorption ◽  
Ultrasound Assisted ◽  
The Rich ◽  
Emulsification Microextraction

Abstract In this work, a method using ultrasound-assisted emulsification microextraction (USAEME) without the use of ligands in an online system for preconcentration and determination of cadmium was developed. The method was based on the preconcentration of cadmium by USAEME, employing trichloroethylene as the extraction solvent, and subsequent retention of the rich phase in a mini-column packed with silica gel. The extracted metal was determined by flame atomic absorption spectrometry. The parameters that affect the extraction of cadmium were optimized using the univariate method. Under optimized conditions, the method presented a limit of detection of 0.17 μg/L, a limit of quantification of 0.57 μg/L, an enrichment factor of 56, and a consumptive index of 0.18 mL/min. The accuracy of the method was tested by analyzing the certified reference material, National Institute of Standards and Technology (NIST) 1573 (tomato leaves). The determination of Cd in water (drinking water, bottled water, river water, and seawater) and tea (black and green tea) samples was also performed using the proposed method. The method is simple, efficient, and eco-friendly because it requires low consumption of an organic solvent.

Lactic Acid Determination in Human Plasma Using Ultrasound-Assisted Emulsification Microextraction Followed by Gas Chromatography

2016 ◽  
Vol 69 (4) ◽  
pp. 451 ◽  
Author(s):  
Parvin Shahdousti ◽  
Rezvan Shojaee ◽  
Mohammad Aghamohammadi ◽  
Behrang Harooni
Keyword(s):  
Gas Chromatography ◽  
Lactic Acid ◽  
Human Plasma ◽  
Limit Of Detection ◽  
Aqueous Sample ◽  
Extraction Solvent ◽  
Relative Standard ◽  
Ultrasound Assisted ◽  
Emulsification Microextraction

A rapid, sensitive, and accurate analytical method was developed for determination of lactic acid (LA) in human plasma to monitor lactic acidosis. This method was based on an ultrasound-assisted emulsification microextraction (USAEME) method followed by gas chromatography with flame ionization detection (GC–FID). Derivatization of LA was carried out by a low density alcoholic solvent which performs both as an extraction solvent and derivatization agent, simultaneously. In this procedure, 100 μL of binary mixtures of pentan-1-ol with toluene (70 : 30, v/v %) was slowly injected into a 10 mL acidified aqueous sample of LA placed into an ultrasonic water bath. The resulting emulsion was centrifuged and after derivatization, 2 μL of organic phase was analysed by GC–FID. The effective variables were evaluated to optimize the efficiency of USAEME. Under the optimum conditions, good linearity in the range of 0.06–7.77 mmol L–1 was obtained with a correlation coefficient (R2) of 0.991 and a limit of detection (LOD) of 0.04 mmol L–1 for water samples. The inter-day and intra-day repeatability of the proposed method in human plasma were evaluated in terms of the relative standard deviation (RSD %) and were found to be <10 %. The results revealed that the USAEME–GC–FID method can be applied successfully for determination of LA in human plasma samples with satisfactory accuracy and precision.

scholarly journals Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh
Keyword(s):  
Ionic Liquid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
Flame Atomic Absorption ◽  
Relative Standard

AbstractA rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C6py][PF6]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L−1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L−1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2–166 µg L−1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

scholarly journals Determination of Copper in Water and Plant Samples by Flame Atomic Absorption Spectrometry After Preconcentration on Octadecyl Silica Membrane Disks Modified with a Recently Synthesized Schiff's Base

2008 ◽  
Vol 91 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Tayebeh Shamspur ◽  
Ali Mostafavi ◽  
Iran Sheikhshoaie
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Minimal Amount ◽  
Aqueous Samples ◽  
Silica Membrane ◽  
Flame Atomic Absorption

Abstract A simple, selective, reliable, and sensitive method for the determination of trace amounts of Cu2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 102 g/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.

scholarly journals Flow-Injection Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Cadmium in Solid and Semisolid Milk Products Coupling a Continuous Ultrasound-Assisted Extraction System with the Online Preconcentration on a Chelating Aminomethylphosphoric Acid Resin

2006 ◽  
Vol 89 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Sheila Cancela ◽  
M Carmen Yebra
Keyword(s):  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Acid Extraction ◽  
Ultrasound Assisted Extraction ◽  
Milk Products ◽  
Flame Atomic Absorption ◽  
Assisted Extraction ◽  
Ultrasound Assisted

Abstract A new sensitive and low-cost method that combines continuous acid extraction, online preconcentration, and flame atomic absorption spectrometry for cadmium determination at g levels in solid and semisolid milk products is described. A continuous ultrasound-assisted extraction system is used to carry out the dynamic acid extraction step. The acid extract is preconcentrated online on a minicolumn packedwith a chelating resin (Chelite P,with aminomethylphosphoric acid groups), and the retained cadmium is elutedwith hydrochloric acid and continuously monitored by flame atomic absorption spectrometry. An experimental design (Plackett-Burman 263/16) is used to optimize the continuous extraction and the preconcentration step. The method allowed a total sampling frequency of 28 samples/h. A good precision of the whole procedure (3.0% relative standard deviation) for a cheese sample containing 0.103 0.004 g/g Cd (dry mass), a high enrichment factor (20.5), and detection and quantification limits of 0.014 and 0.067 g/g, respectively, for a 60 mg of sample were obtained with this methodology. The method was successfully applied to the determination of trace amounts of cadmium in solid and semisolid milk products, such as cheese and yogurt samples.

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