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.

scholarly journals Adsorption-Photometric and Test-Determination of Fe(III) in Natural Water Using Silica Lyer-by-Lyer Modified with Polyhexamethylene Guanidine and Ferron

2020 ◽  
pp. 349-362
Author(s):  
Svetlana L. Didukh-Shadrina ◽  
Olga V. Buyko ◽  
Vladimir N. Losev
Keyword(s):  
Natural Water ◽  
Mineral Water ◽  
Diffuse Reflectance ◽  
Reflectance Spectrum ◽  
Diffuse Reflectance Spectrum ◽  
Photometric Determination ◽  
Test Method ◽  
Test Determination ◽  
Polyhexamethylene Guanidine

Silica based adsorbent sequentially modified with polyhexamethylene guanidine and 7-iodine-8-hydroxyquinoline-5-sulfonic acid (Ferron) was proposed for adsorption-photometric and test-determination of Fe(III) in natural water. During adsorption of Fe(III) from solutions with pH 2.0-3.5 adsorbent became green colored. Formation of green-colored surface complex of Fe(III) with Ferron with the maximum in diffuse reflectance spectrum at 600 nm was used for developing the procedure of its adsorption-photometric determination. Detection limit calculated by 3s-criterion was 0.03 μg/0.1 g of adsorbent (3 μg/L if the adsorption was carried out from 10 mL of solution); the analytical range was 10 – 220 μg/L. Test-method was proposed for quick visual determination of Fe(III) in natural water in the variant of test-scale. Developed procedures were tested for determination of iron in natural river water of Krasnoyarskii kray and mineral water “Zagorie”

Determination of Trif luralin, Diallate, Triallate, Atrazine, Barban, Diclofop-Methyl, and Benzoylprop-Ethyl in Natural Waters at Parts per Trillion Levels

1983 ◽  
Vol 66 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Hing-Biu Lee ◽  
Alfred S Y Chau
Keyword(s):  
Natural Water ◽  
Water Samples ◽  
Natural Waters ◽  
Florisil Column ◽  
Multiresidue Method ◽  
Analytical Scheme ◽  
Acid Type ◽  
Neutral Compounds ◽  
Cleanup Procedure

Abstract A sensitive multiresidue method is presented for the determination of 7 neutral herbicides in natural waters, with practical detection limits between 5 and 100 ng/L(ppt). The extraction was carried out at pH ≼1, using dichloromethane, so that acid-type herbicides can also be incorporated in the future. The entire cleanup procedure involves base partitioning, preliminary cleanup and fractionation on a 10% deactivated Florisil column, and final cleanup of the fractions on an activated Florisil column. However, the cleanup procedure is flexible enough to permit the analyst to use some or all of the cleanup steps, depending on the herbicide levels of interest. Recoveries of the 7 herbicides from distilled and natural water samples were between 82 and 104% at 2 fortification levels. Furthermore, this basic analytical scheme has been demonstrated, separately, to be effective in the determination of other neutral compounds such as PCBs, 18 organochlorine pesticides, and chlorobenzenes and thus has a potential to be developed into a multiclass, multiresidue method.

A batch method for the determination of ion-exchangeable trace metals in natural waters

1977 ◽  
Vol 28 (3) ◽  
pp. 397 ◽  
Author(s):  
BT Hart ◽  
HR Davies
Keyword(s):  
Trace Metals ◽  
Natural Water ◽  
Water Samples ◽  
Natural Waters ◽  
Field Studies ◽  
Metal Species ◽  
Batch Method ◽  
Chelex 100 ◽  
Natural Water Samples

A batch method for the determination of ion-exchangeable trace metals in natural waters is reported. The technique employs the resin Chelex 100 and has been tested for Cd, Cu, Pb, Zn and Fe using both synthetic and natural water samples. Quantitative recovery of ionic spikes was achieved and uptake was found to occur rapidly, being virtually completed within 1 h. Evidence is provided for the presence in the natural water samples of stable bound trace metal species. This batch method should prove particularly useful for field studies of the physicochemical forms of trace metals in aquatic environments.

Evaluation of XAD-2 for Multiresidue Extraction of Organochlorine Pesticides and Polychlorinated Biphenyls from Natural Waters

1977 ◽  
Vol 60 (1) ◽  
pp. 224-228 ◽  
Author(s):  
John A Coburn ◽  
Ilze A Yaldmanis ◽  
Alfred S Y Chau
Keyword(s):  
Polychlorinated Biphenyls ◽  
Organochlorine Pesticides ◽  
Silica Gel ◽  
Natural Water ◽  
Water Samples ◽  
Natural Waters ◽  
Extraction Procedure ◽  
Distilled Water ◽  
Fractionation Column ◽  
Control Samples

Abstract The Amberlite polymeric resin, XAD-2, was evaluated for multiresidue extraction of ng/L levels of several organochlorine pesticides and polychlorinated biphenyls (PCBs) from fortified distilled water and from fortified and unfortified natural waters. Recoveries from 1 L distilled water samples fortified with 10—100 ng of 10 organochlorine pesticides averaged 96%. Recoveries averaged 85% for XAD-2 resin extraction of fortified natural samples collected from across Canada. Unfortified control samples contained no detectable levels of any of the pesticides used in the fortification. The resin is not suitable for extracting Mirex from natural water; only about 50% of added Mirex was recovered. Recoveries of PCBs from 2 L natural water samples, fortified with 250 ng PCBs/L and corrected for losses on the silica gel fractionation column and apparent PCB content of the control samples, ranged from 78 to 86%. Blanks for the resin extraction procedure were very low, averaging 4 ng PCBs/L.

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 Separation and Preconcentration of Trace Amounts of Manganese and Nickel from Natural Water Samples by a Diimine Derivative Schiff Base-Coated Silica-Gel Minicolumn

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Reyhaneh Rahnama ◽  
Mohammad Reza Jamali
Keyword(s):  
Schiff Base ◽  
Silica Gel ◽  
Natural Water ◽  
Water Samples ◽  
Sample Volume ◽  
Flame Atomic Absorption ◽  
Natural Water Samples ◽  
Relative Standard ◽  
Separation And Preconcentration ◽  
Flame Atomic Absorption Spectrometer

An efficient method for preconcentration of trace amounts of Mn (II) and Ni (II) ions by using a minicolumn (10 mm × 30 mm i.d.) filled with a diimine derivative Schiff base on silica-gel has been reported. The retained analytes on the column were recovered with 5 mL of mixture of nitric acid 5 mol L−1and methanol (1 : 1) and were determined by a flame atomic absorption spectrometer. Different factors including pH of sample solution, sample volume, amount of sorbent, eluent volume, and interference of other ions have been studied and the optimized conditions developed were utilized for the trace determination of Mn (II) and Ni (II) in natural water samples. The recoveries for the analytes under the optimum working conditions were higher than 98%. The relative standard deviations of the determinations (10 replicate analyses) at 25 μg L−1of Mn (II) and Ni (II) were 2.5% and 2.3%, respectively. The limit of the detection (3s,n=10)for analytes were found to be 0.20 μg L−1for Mn (II) and 0.15 μg L−1for Ni (II). The proposed method was applied to the analysis of natural water samples with satisfactory results.

scholarly journals Determination of Bentazone in Waters by Solid-Phase Spectrofluorimetry

1996 ◽  
Vol 79 (2) ◽  
pp. 567-570 ◽  
Author(s):  
José Luis Vilchez ◽  
Diego Torres-Bustos ◽  
Rosario Blanc ◽  
Alberto Navalón
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Relative Standard Deviation ◽  
Natural Water ◽  
Water Samples ◽  
Solid Phase ◽  
Excitation Wavelength ◽  
Relative Standard ◽  
Sensitive Method

Abstract A sensitive method for determining trace amounts of bentazone was developed. The method is based on solid-phase spectrofluorimetry. Bentazone was fixed on a dextran-type anion-exchange gel, and the fluorescence of the gel, packed in a 1 mm thick quartz cell, was measured directly at an excitation wavelength of 338 nm and an emission wavelength of 436 nm by using a solid-phase attachment. The applicable concentration range was 2.0–120.0 μg/L, with a detection limit of 0.4 μg/L. The relative standard deviation at the 30.0 μg/L level was 1.2%. The method was used to determine bentazone in natural water samples. Recoveries were 96.0–102.5%.

Sign in / Sign up

Export Citation Format

Share Document