Search results

Search:
in the keywords: Water samples

Sort By:

Limit search:

Determination of three phenoxyacid herbicides in environmental water samples by the application of dispersive liquid-liquid microextraction coupled with micellar electrokinetic chromatography

100%

Ma Y., Wen Y., Li J., Wang H., Ding Y., Chen L.

Open Chemistry

2013

vol. 11

issue 3

394-403

Abstract 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 [...]

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

88%

Abdolmohammad-Zadeh H., Ebrahimzadeh E.

Open Chemistry

2010

vol. 8

issue 3

617-625

A 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. [...]

Refine search results

2 Open Chemistry

1 2013

1 2010

1 Abdolmohammad-Zadeh H.

1 Chen L.

1 Ding Y.

1 Ebrahimzadeh E.

1 Li J.

1 Ma Y.

1 Wang H.

1 Wen Y.

Search results

Determination of three phenoxyacid herbicides in environmental water samples by the application of dispersive liquid-liquid microextraction coupled with micellar electrokinetic chromatography

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