Wyniki wyszukiwania - BazTech

1

Recycling of styrofoam waste: synthesis, characterization and application of novel phenyl thiosemicarbazone surface

Siyal A.N., Memon S.Q., Khuhawar M.Y.

Polish Journal of Chemical Technology

|

2012

|

Vol. 14, nr 4

11-18

EN

An attempt has been made to recycle Styrofoam waste to a novel functional polymer, Phenyl thiosemicarbazone surface (PTS). Polystyrene (PS) obtained from Styrofoam waste was acetylated and then condensed to PTS by reacting it with 4-Phenyl-3-thiosemicarbazide ligand and characterized by FT-IR spectroscopy and elemental analysis. Synthesized PTS was applied successfully for the treatment of lead contaminated water by batch extraction method. Sorption variables were optimized (pH 8, adsorbent dose 53mg, initial Pb(II) ion concentration 10mgl-1 and agitation time 90min) by factorial design approach. Lead uptake by PTS was found much sensitive to the pH of Pb(II) ion solution. The maximum removal (99.61%) of Pb(II) ions was achieved at optimum conditions. The Langmuir and D-R isotherm study suggested the monolayer, favorable (RL=0.0001-0.01) and chemisorption (E=20.41š0.12kJmol-1) nature of the adsorption process. The sorption capacity of PTS was found to be 45.25š0.69mgg-1. The FT-IR spectroscopy study showed the involvement of nitrogen and sulphur of thiosemicarbazone moiety of PTS for the uptake of Pb(II) ions by fi ve membered chelate formation.

2

Micellar electrokinetic chromatographic separation and quantitative analysis of thorium, uranium, gold, and mercury from environmental ore samples

Mallah A, Memon S. Q., Khuhawar M.Y., Solangi A. R., Bhanger M. I.

Acta Chromatographica

|

2011

|

Vol. 23, no. 1

69--80

EN

A rapid and reliable analytical procedure has been developed for the separation and analysis of dioxouranium, thorium, gold, and mercury by micellar electrokinetic chromatography (MEKC) using bis(acetylacetone)ethylenediamine (H2AA2en) as complexing reagent. Under the optimized conditions (64 mM borate buffer containing 12.25 mM SDS and 13% acetonitrile, pH 8.0, 25 kV, 311 nm as detection wavelength) the ions were separated within 5.0 min. Linear dynamic ranges were 1–5, 8–42, 10–50, and 2–40 μg mL -1, respectively, for gold, mercury, thorium, and uranium and the respective detection limits were 0.66, 3.33, 1.6, and 3.3 μg mL -1. The applicability of method has been evaluated by application to uranium and thorium from ore samples.

3

Micellar electrokinetic chromatographic separation and analysis of thorium, uranium, gold, and mercury in environmental ore samples

Mallah A, Memon S. Q., Solangi A. R., Khuhawar M. Y., Bhanger M. I.

Acta Chromatographica

|

2010

|

Vol. 22, no. 3

405--417

EN

A fast and reliable analytical procedure has been developed for separation and analysis of dioxouranium, thorium, gold, and mercury by micellar electrokinetic chromatography (MEKC) using bis(acetylacetone)ethylenediamine (H 2 AA 2 en) as complexing reagent. Under the optimized conditions (64 mM borate buffer containing 12.25 mM SDS and 13% acetonitrile, pH 7.99; 25 kV; detection wavelength 311 nm), other ions present were separated within 5 min. Linear dynamic ranges 1–5, 8–42, 10–50, and 2–40 μg mL -1 and detection limits 0.66, 3.33, 1.6, and 3.3 μg mL -1, respectively, were achieved for gold, mercury, thorium, and uranium. The applicability of method was evaluated by analysis of uranium and thorium in ore samples.

4

Liquid chromatographic analysis of mercury(ii) and cadmium(ii) using dimethylglyoxal bis-(4-phenyl-3-thiosemicarbazone) as derivatizing reagent

Arain G. M., Khuhawar M. Y.

Acta Chromatographica

|

2008

|

Vol. 20, no. 1

25-41

EN

A liquid chromatographic method based on precolumn derivatization with dimethylglyoxal bis-(4-phenyl-3-thiosemicarbazone) (DMBS) has been developed for quantitative analysis of Hg(II) and Cd(II) and separation of Hg(II), Cd(II), VO(II), and Ag(I). The complexes were separated on a 25 cm × 4.6 mm i.d., 10-µm particle, C 18 column with methanol-water-acetonitrile-1 mM tetrabutylammonium bromide (TBAB) 48:32:18:2 (v/v) as mobile phase at a flow rate of 1 mL min -1. UV detection was at 258 nm. Linear calibration plots were obtained in the ranges 0.5-10.0 µg mL -1 for Hg(II), 0.5-12.0 µg mL -1 for Cd(II), 2-10 µg mL -1 for V, and 1.5-12.5 µg mL -1 for Ag(I), with detection limits of 50, 125, 400 and 400 pg, respectively, per 20-µL injection. Several metal ions tested did not affect the determination of mercury and cadmium. The method was used for quantitative analysis of Hg and Cd in freshwater fish, tea leaves, and tobacco. The Hg content of the samples was 0.067-0.284, 0.011-0.123, and 0.042-0.261 µg -1, respectively, with relative standard deviations (RSD) from 0.8 to 4.4%. The Cd content of fish, tea leaves, and tobacco was 0.0068-0.0236, 0.233-0.712, and 0.171-1.126 µg -1, respectively, with RSDs from 1.4 to 4.7%. Higher concentrations of Hg and Cd were observed in blood samples from smokers on dialysis than in those from healthy nonsmokers.

5

Quantitative analysis of eight cephalosporin antibiotics in pharmaceutical products and urine by capillary zone electrophoresis

Solangi A. R., Memon S. Q., Khuhawar M. Y., Bhanger M. I.

Acta Chromatographica

|

2007

|

No. 19

81-96

EN

A simple and rapid capillary zone electrophoretic (CZE) method has been established for separation and quantification of a mixture of eight ce-phalosporins – cefadroxil (CFL), cefixime (CIX), cefuroxime sodium (CFR), ceftriaxone sodium (CTR), ceftizoxime (CFT), cefaclor (CFC), cefradine (CFD), and cefotoxime (CTA). Conditions affecting the separation were pH, buffer concentration, and applied potential. Separation was performed in less than 11 min with 50 mM sodium tetraborate buffer, pH 9.0, and an applied potential of 30 kV. Reproducible separation was achieved and calibration plots were linear over two to three orders of magnitude of analyte concentration. Limits of detection were in the range 0.5–5 µg mL–1. De-tection was by UV absorbance at 214 nm. When the method was assessed for analysis of cephalosporins in pharmaceutical preparations and in urine, relative standard deviations (RSD, n = 4) were in the range 0.3–1.9%.

6

High-performance liquid chromatographic determination of isoniazid, pyrazinamide, and indomethacin in pharmaceutical preparations

Khuhawar M. Y., Rind F. M. A., Rajper A. D.

Acta Chromatographica

|

2005

|

No. 15

269-275

EN

Isoniazid (INH) has been quantitated after precolumn derivatization with 5-methylfuran-2-carboxaldehyde (MFA). Chromatography was performed on a 150 mm × 4.6 mm i.d. YMC-ODS column with water–methanol–tetrahydrofuran, 59:39:2 (v/v) as a mobile phase at a flow rate of 2 mL min-1. Detection was performed at 328 nm. By adoption of this proc-dure pyrazinamide (PZA) and indomethacin (IM) separated completely and could be determined together with INH. Linear calibration plots were obtained between 1.4 and 5.5 µg mL-1 for INH, between 6.2 and 30.8 µg mL-1 for PZA, and between 10.7 and 64.08 µg mL-1 for IM. The method of analysis was used for quantitation of INH, PZA, and IM in pharmaceutical preparations with a coefficient of variation <1%.