scholarly journals Vortex-assisted liquid–liquid microextraction combined with spectrophotometry for the determination of trace nitrite in water samples

2017 ◽  
Vol 17 (5) ◽  
pp. 1225-1231 ◽  
Author(s):  
Yang Jiao ◽  
Jianping Yu ◽  
Yaling Yang

A vortex-assisted liquid–liquid microextraction (VALLME) method using isooctanol as extractant followed by spectrophotometry was developed for the extraction and determination of trace nitrite in water samples. The method is based on selective ion-pairing complex (I3− MG+) formation of triiodideanion I3− with cationic dye malachite green (MG) at pH 3.0, and its subsequent extraction in an organic solvent. The extracted organic solvent-rich phase is diluted with methanol, and its absorbance is measured against an analyte blank at 630 nm. The variables affecting VALLME efficiency were investigated, and a set of optimized conditions was obtained. Under the optimum conditions, the linear range of nitrite was from 1.0 to 100 ng mL−1. The relative standard deviations (n = 10) were 2.1–3.9% and the limit of detection was 0.5 ng mL−1 and was successfully applied to the determination of nitrite in environmental water.

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
J. Pérez-Outeiral ◽  
E. Millán ◽  
R. Garcia-Arrona

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.


2012 ◽  
Vol 518-523 ◽  
pp. 1379-1382
Author(s):  
Ying Chun Yang ◽  
Qian Sun ◽  
Chong Shu Yi ◽  
Zhi Xiang Ye ◽  
Li Mo

A rapid and effective method, the dispersive liquid-liquid microextraction(DLLME) with gas chromatography, has been developed for the extraction and determination of OCP in environmental water samples. The factors relevant to the efficiency of DLLME were investigated and optimized. Under the optimum conditions, such as 150μL of dichloromethane as extraction solvent, 1.2 mL acetone as dispersive agent, 8 minutes extraction time, and without salt addition, the linear response of this method was in the range of 0.5~5000μg L−1 (r = 0.9981), the relative standard deviation (RSD) for 500μg L−1 and 1000μg L−1 of OCP was 5.2% and 12.6% (n = 6), respectively. The detection limit (3σ) was 0.08 μg L−1. The developed method was successfully applied to the determination of trace amount of OCP in three kinds of real environmental water samples, the spiked recoveries were in the range of 87.4%~108.0%.


2013 ◽  
Vol 11 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Yanling Ma ◽  
Yingying Wen ◽  
Jinhua Li ◽  
Hua Wang ◽  
Yangjun Ding ◽  
...  

AbstractAbstract An efficient method based on dispersive liquid-liquid microextraction coupled with micellar electrokinetic chromatography has been developed for determination of three phenoxyacid herbicides (PAs) of 2,4-dichlorophenoxybutyric acid (2,4-DB), dicamba and 2,4-dichlorophenoxyacetic acid (2,4-D), in environmental water samples. The types and volumes of extracting and dispersing solvents, ionic strength, extraction and centrifugation time and centrifugation speed were investigated. Successful separation of the three PAs was achieved within 7 min, by using the background electrolyte solution consisting of 10 mmol L−1 sodium tetraborate, 25 mmol L−1 sodium dodecyl sulfate and 15% (v/v) methanol, at pH 9.75. Excellent analytical performances were attained, such as good linear relationships (R ≥0.9993) between peak area and concentration for each PAs from 10–1000 ng mL−1, limits of detection of 1.56–1.91 ng mL−1, and intra-day precisions at two spiked levels in terms of migration time and peak area within the range of 0.22–0.42% and 3.88–6.39%, respectively. Enrichment factors of 2,4-DB, dicamba and 2,4-D were 180, 151 and 216, respectively. The method recoveries obtained at fortified 20.0, 50.0 and 100.0 ng mL−1 for lake, river and reservoir water samples varied from 67.91 to 119.07% with the relative standard deviation of 1.47–6.89%. Graphical abstract


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Siroos Shojaei ◽  
Saeed Shojaei ◽  
Arezoo Nouri ◽  
Leila Baharinikoo

AbstractAs the world population continues to grow, so does the pollution of water resources. It is, therefore, important to identify ways of reducing pollution as part of our effort to significantly increase the supply of clean and safer water. In this study, the efficiency of ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) as a fast, economical, and simple method for extraction malachite green (MG) and rhodamine B (RB) dyes from water samples is investigated. In optimal conditions, the linear dynamic range (LDR) for RB and MG is 7.5–1500 ng mL−1 and 12–1000 ng mL−1, respectively. The limit of detection (LOD) is 1.45 ng mL−1 and 2.73 ng mL−1, and limit of quantification (LOQ) is 4.83 ng mL−1 and 9.10 ng mL−1 for RB and MG, respectively. Extraction efficiency is obtained in the range of 95.53–99.60%. The relative standard deviations (RSD) in real water and wastewater samples are less than 3.5. The developed method is used successfully in the determination of RB and MG dyes from water samples and there are satisfactory results.


2021 ◽  
Vol 50 (5) ◽  
pp. 1297-1307
Author(s):  
Sohaib Jumaah Owaid Luhaib ◽  
Noorfatimah Yahaya ◽  
Anas Alshishani ◽  
Maizatul Najwa Jajuli ◽  
Mazidatulakmam Miskam

A new analytical method based on vortex-assisted liquid-liquid microextraction with back extraction (VALLME-BE) coupled with high performance liquid chromatography was developed for the simultaneous determination of antidiabetic drugs; repaglinide, glibenclamide, and glimepiride in water samples. Chromatographic separation was achieved using C18 column (250 × 4.6 mm × 5 µm) and methanol-phosphate buffer (pH3.7) in the ratio of 70:30 v/v as a mobile phase at a flow rate of 1 mLmin-1. VALLME-BE was performed using 200 μL of n-octane dispersed into the aqueous sample (10 mL) with the aid of vortexing agitation. Then, the analytes were back-extracted from the organic solvent to 0.05 M NaOH (40 µL). Under these conditions, enrichment factor of 155-fold was achieved. The developed VALLME-BE method showed excellent linearity in the range of 30 to 1000 µgL-1 with limit of detection (LOD) of 0.41-1.66 µgL-1 and limit of quantification (LOQ) of 1.38-5.54. 41-1.66 µgL-1. VALLME-BE was applied for the determination of repaglinide, glibenclamide and glimepiride in water samples with the recoveries ranged from 83-109%. The relative standard deviation for inter-day and intra-day precision was less than 9.9%.


2020 ◽  
Vol 67 (4) ◽  
pp. 1092-1099
Author(s):  
Armin Fallah ◽  
Mohammad Reza Hadjmohammadi

In this study, a rapid and efficient method has been used for the extraction and determination of morin and quercetin in fruit juice samples based on air-assisted liquid-liquid microextraction based on solidification of floating organic droplet and HPLC-UV. The effects of 7 important parameters on the extraction recovery were examined and were optimized by Plackett-Burman design and Central Composite design. According to the Plackett-Burman design results, ionic strength of the sample solutions, the aspiration/dispersion cycles, and the rate and time of centrifuge did not show significant effects on the extraction of morin and quercetin. The optimized conditions of extraction were as follows; the volume of the extraction solvent of 83.6 μL, pH of 4.34 for the sample, and 1-undecanol as extraction solvent. Under these conditions, the linear calibration curve was in the ranges of 1–1000 ng/mL and 0.5–1000 ng/mL for morin and quercetin, respectively, with the determination coefficient values above 0.99. The limit of detection of morin and quercetin was 0.3 and 0.2 ng/mL, respectively. The extraction recoveries for 10 ng/mL of morin and quercetin were 98.9% and 96.5%, respectively; while, relative standard deviations (n = 3) were lower than 3.2%.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Wajid Ali Khan ◽  
Muhammad Balal Arain ◽  
Hashmat Bibi ◽  
Mustafa Tuzen ◽  
Nasrullah Shah ◽  
...  

AbstractIn this study, an extremely effective electromembrane extraction (EME) method was developed for the selective extraction of Cu(II) followed by Red-Green-Blue (RGB) detection. The effective parameters optimized for the extraction efficiency of EME include applied voltage, extraction time, supported liquid membrane (SLM) composition, pH of acceptor/donor phases, and stirring rate. Under optimized conditions, Cu(II) was extracted from a 3 mL aqueous donor phase to 8 µL of 100 mM HCl acceptor solution through 1-octanol SLM using an applied voltage of 50 V for 15 min. The proposed method provides a working range of 0.1–0.75 µg·mL−1 with 0.03 µg·mL−1 limit for detection. Finally, the developed technique was applied to different environmental water samples for monitoring environmental pollution. Obtained relative recoveries were within the range of 93–106%. The relative standard deviation (RSD) and enhancement factor (EF) were found to be ≤4.8% and 100 respectively. We hope that this method can be introduced for quantitative determination of Cu(II) as a fast, simple, portable, inexpensive, effective, and precise procedure.


2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh

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.


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