scholarly journals Factors Affecting Multiresidue Determination of Priority Herbicides when Using Solid-Phase Microextraction

2002 ◽  
Vol 85 (2) ◽  
pp. 486-493 ◽  
Author(s):  
Dimitra A Lambropoulou ◽  
Ioannis K Konstantinou ◽  
Triantafyllos A Albanis
Keyword(s):  
River Water ◽  
Water Samples ◽  
Natural Waters ◽  
Sea Water ◽  
Solid Phase ◽  
Time Profile ◽  
Factors Affecting ◽  
Stirring Rate ◽  
Relative Standard

Abstract A solid-phase microextracton (SPME) procedure was developed for the determination of 10 selected organonitrogen herbicides (s-ethyl dibropylthiocarbamate [EPTC], molinate, propachlor, trifluralin, simazine, atrazine, propazine, terbuthylazine, alachlor, and prometryn) and was tested with various natural waters. Gas chromatography coupled with flame thermionic and mass spectrometric detection was used for quantitation. For this purpose, polydimethylsiloxane and polyacrylate fibers were used and the factors affecting the SPME process such as pH, ionic strength, methanol content, memory effect, stirring rate, and adsorption-time profile were investigated and optimized. By using spiked liquid chromatography water, optimal factors were determined to be 25% salt, <0.5% methanol, stirring rate of 960 rpm, pH 4, and an equilibrium time of 30 min. These conditions were used in further studies of the fibers and in analysis of natural water samples. The method was applied to spiked natural waters such as ground water, sea water, lake water, and river water at a concentration range of 0.5–10 μg/L. Limits of detection ranged from 5 to 90 ng/L, and precision ranged from 5 to 15% (as relative standard deviation), depending on the pesticide, fiber, and detector used. The recoveries of herbicides were 70.2–118.4%, and the average r2 values of the calibration curves were >0.99 for all analytes. The results demonstrate the suitability of the SPME method to determine these organonitrogen herbicides in various natural waters. River water samples originating from the Epirus region (Northwestern Greece) were analyzed to verify the performance of the optimized method by comparing the results obtained by SPME with those obtained by using conventional solid-phase extraction of the selected herbicides.

scholarly journals Amine-functionalized magnetic activated carbon as an adsorbent for preconcentration and determination of acidic drugs in environmental water samples using HPLC-DAD

2020 ◽  
Vol 18 (1) ◽  
pp. 1218-1229 ◽  
Author(s):  
Mpingana Ndilimeke Akawa ◽  
Kgogobi Mogolodi Dimpe ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Activated Carbon ◽  
River Water ◽  
Water Samples ◽  
High Performance ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Array Detector ◽  
Acidic Drugs ◽  
Relative Standard

AbstractIn the present study, a convenient and highly effective method was developed for the quantification of acidic drugs in wastewater and river water samples. Ultrasonic-assisted magnetic solid phase extraction employing magnetic waste tyre-based activated carbon nanocomposite functionalized with [3-(2-aminoethylamino)propyl]trimethoxysilane as a cost-effective and efficient adsorbent was used for the extraction and preconcentration of acidic drugs (naproxen [NAP], ketoprofen (KET) and diclofenac [DIC]). The quantification of target analytes was achieved by high‐performance liquid chromatography with diode array detector. Under optimum conditions, the detection limit, quantification limit and relative standard deviation obtained for the analytes of interest ranged from 0.38 to 0.76, 1.26 to 2.54 µg L−1 and 2.02 to 4.06%, respectively. The applicability of the developed method was assessed by the spike recovery tests and the relative recoveries proved that the method is reliable for the determination of acidic drugs in wastewater. Thereafter, the method was applied successfully for the determination of NAP, KET and DIC in river water, influent and effluent wastewater.

scholarly journals Determination of the fenvalerate insecticide in natural waters by a photochemically-induced fluorescence method

2015 ◽  
Vol 34 (2) ◽  
pp. 245 ◽  
Author(s):  
Diène Diégane Thiaré ◽  
Atanasse Coly ◽  
Diégane Sarr ◽  
Abdourakhmane Khonté ◽  
Amadou Diop ◽  
...  
Keyword(s):  
Natural Waters ◽  
Sea Water ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Irradiation Time ◽  
Tap Water ◽  
Analytical Sensitivity ◽  
Photochemically Induced Fluorescence ◽  
Relative Standard

<p>The fenvalerate pyrethroid insecticide was determined in various types of natural waters of Senegal by means of a newly-developed, simple, rapid and very sensitive photochemically-induced fluorescence (PIF) method. The PIF method was optimized with respect to the irradiation time, solvent and pH. The obtained calibration curves yielded correlation coefficients very close to unity. The limit of detection (LOD) and of quantification (LOQ) values were very low (LOD = 0.01–0.66 ng/ml and LOQ = 0.04–2.20 ng/ml, according to the solvent), and the relative standard deviation (RSD) values were small, ranging between 0.1 and 1.5 %, which indicated a very good analytical sensitivity and a great repeatability of PIF. Recovery studies were performed on spiked distilled water, tap water, sea water, well water, river water and draining water samples of Senegal, using the liquid-liquid extraction (LLE), solid phase extraction (SPE), and standard addition procedures. Satisfactory recovery results (about 85–121%) were obtained for the determination of fenvalerate in an aquatic environment.</p>

Development of an on-line solid phase extraction method based on new functionalized magnetic nanoparticles. Use in the determination of mercury in biological and sea-water samples

Talanta ◽  
2016 ◽  
Vol 153 ◽  
pp. 228-239 ◽  
Author(s):  
Elisa Vereda Alonso ◽  
M.M. López Guerrero ◽  
Pilar Colorado Cueto ◽  
José Barreno Benítez ◽  
José Manuel Cano Pavón ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Solid Phase Extraction ◽  
Water Samples ◽  
Extraction Method ◽  
Sea Water ◽  
Solid Phase ◽  
Phase Extraction ◽  
Functionalized Magnetic Nanoparticles ◽  
On Line

Atomic Absorption Spectrometric Determination of Arsenite in Water Samples by Graphite Furnace After Extraction with Ammonium sec-Butyldithiophosphate

1984 ◽  
Vol 67 (2) ◽  
pp. 277-280
Author(s):  
Dipankar Chakraborti ◽  
Kurt J Irgolic ◽  
F Adams
Keyword(s):  
Atomic Absorption ◽  
River Water ◽  
Water Samples ◽  
Graphite Furnace ◽  
Dimethylarsinic Acid ◽  
Relative Standard ◽  
Methylarsonic Acid ◽  
Atomic Absorption Spectrometric ◽  
Hexane Solution

Abstract Arsenite—but not arsenate, methylarsonic acid, or dimethylarsinic acid—is extracted from water samples by 5 mL of a 0.01M hexane solution of rec-dibutylthiophosphate. A 10 μL aliquot of the extract is injected into an atomic absorption spectrometer with a graphic furnace for the determination of arsenic. The calibration curve is linear to 1500 Dg As. Quantities of arsenic as low as 100 ng As (0.2 ppb As when contained in 500 mL) can be confidently determined. The method was tested with natural river water and synthetic river water. The relative standard deviations associated with the recoveries of arsenite from natural water and synthetic river water spiked with arsenite range from 4.8 to 8.0%. Ten to 15 arsenite determinations can be completed in 1h.

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.

scholarly journals SILICA GEL MODIFIED WITH 1,2-NAPHTHOQUINONE THIOSEMICARBAZONE FOR SORPTION-PHOTOMETRIC DETERMINATION OF MERCURY (II)

2017 ◽  
pp. 52-55
Author(s):  
M. Zui ◽  
S. Diduk
Keyword(s):  
Silica Gel ◽  
Natural Water ◽  
Water Samples ◽  
Natural Waters ◽  
Photometric Determination ◽  
Test Method ◽  
Relative Standard ◽  
Edta Solution ◽  
Effects Of Ph

A sorption-photometric test method for preconcentration and determination of mercury (II) was developed using silica gel modified with 1,2-naphthoquinone thiosemicarbazone. Modification of silica gel with a reagent was carried out from the chloroform-hexane solution for 3 hours. Pocket photometer was used for the measurement of reflected (transmitted) light from silica modified after sorption of thiosemicarbazonate of Hg(II). The adsorption capacity of the sorbent has been found to be 35 μmol g-1 for 1,2-naphthoquinone thiosemicarbazone. The effects of pH, sorption time, the volume of aqueous solution were studied. In the optimal conditions (pH 3.0; 5 min; 25°C) the extraction recovery of mercury is 90–95%. The range of concentrations of mercury (ІІ) is 50–600 µg L–1, the detection limit (S/N = 3) is 23 µg L–1. The method is tested in the model tap and natural water samples, relative standard deviation for 50 μg L−1 of Hg(II) is below 9.0 % (n = 3). The interference effect of the most common heavy metals in natural water, as Fe (III), Zn (II) and Mn (II) ions were studied. The EDTA solution was added for the binding of these metals, which forms strong colorless complexes with EDTA. We have shown that in the presence of 0,01 M EDTA solution Fe (III), Zn (II) and Mn (II) ions, each up to 500 μg L−1, do not interfere with the determination of mercury (II) at its content of 50 μg L−1. The method can be used for the determination of mercury in the sewage of various industries and natural waters with its high content. The proposed method is inexpensive, simple, fast, and environmentally friendly for the determination of the micro quantities of mercury (II) in the water samples.

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