M. Y. Khuhawar

Use of modified sorbent for the separation and preconcentration of chromium species from industrial waste water.

A simple and sensitive method based on solid phase extraction (SPE) on acetyl acetone modified XAD-16 has been established for separation of Cr (III) and Cr (VI) from and industrial water samples. Two forms of chromium showed different exchange capacities at different pH values, viz. Cr (III) selectively retained at pH 5-7 whereas Cr (VI) retained at pH 1. Hence complete separation of the two forms of chromium is possible. Retained species were eluted with 5 mL of 2 mol L(-1) HNO(3) and 2 mol L(-1) NaOH. The detection limit of 0.02 and 0.014 microg mL(-1) was achieved for Cr (III) and Cr (VI), respectively, with an enrichment factor of 100 and 140. Various kinetic and thermodynamic parameters were also determined. The metal ion concentration was measured by atomic Absorption Spectroscopy. The possible retention mechanism is also discussed. The method was successfully applied for the speciation of chromium in industrial water samples.

Quantitative separation of oxytocin, norfloxacin and diclofenac sodium in milk samples using capillary electrophoresis.

A simple, sensitive and rapid method has been developed for simultaneous separation and quantification of three different drugs: oxytocin (OT), norfloxacin (NOR) and diclofenac (DIC) sodium in milk samples using capillary electrophoresis (CE) with UV detection at 220 nm. Factors affecting the separation were pH, concentration of buffer and applied voltage. Separation was obtained in less than 9 min with sodium tetraborate buffer of pH 10.0 and applied voltage 30 kV. The separation was carried out from uncoated fused silica capillary with effective length of 50 cm with 75 microm i.d. The carrier electrolyte gave reproducible separation with calibration plots linear over 0.15-4.0 microg/mL for OT, 5-1000 microg/mL for NOR and 3-125 microg/mL for DIC. The lower limits of detection (LOD) were found to be 50 ng/mL for OT, and 1 microg/mL for NOR and DIC. The method was validated for the analysis of drugs in milk samples and pharmaceutical preparations with recovery of drugs within the range 96-100% with RSD 0.9-2.8%.

Capillary gas chromatographic determination of methylglyoxal from serum of diabetic patients by precolumn derivatization with 1,2-diamonopropane.

Capillary gas chromatographic (GC) determination of methylglyoxal (MGo) was developed on the basis of precolumn derivatization with 1,2-diaminopropane (DAP) at pH 3. The elution was carried out on an HP-5 (30 m x 0.32 mm i.d.) connected with FID. The linear calibration curve was obtained for MGo within 0.09-1.04 microg/ml with detection limit of 40 ng/ml. Dimethylglyoxal (DMGo) also formed derivative with DAP and eluted and separated from MGo at column temperature 100 degrees C for 1 min with heating rate 30 degrees C/min up to 200 degrees C with run time 4.6 min. The nitrogen flow rate was 1.5 ml/min with split ratio of 10:1, v/v. MGo was determined from serum and urine of diabetics and healthy volunteers. The amounts of MGo from serum and urine of diabetic patients were 0.180-0.260 microg/ml and 0.170-0.250 microg/ml with relative standard deviation (R.S.D.) within 1-4% and 1-3%, respectively. The amounts of MGo from serum of healthy volunteers were 0.032-0.054 microg/ml with an R.S.D. of 1.5-3%. DMGo was not detected from the biological fluids and was used as an internal standard.

Syntheses and thermoanalytical studies of some schiff base polymers derived from 5,5′-methylene bis(2-hydroxyacetophenone)

Abstract Six Schiff base polymers poly 5,5′-methylenebis(2-hydroxyacetophenone)1,2-ethylenediimine (PHAen), poly[5,5′-methylenebis(2-hydroxyacetophenone)1,2-propylenediamine] (PHAPn), poly[5,5′-methylenebis (2-hydroxyacetophenone) 1,3-propyledenediamine] (PHAPR), poly[5,5′-methylenebis(2-hydroxyacetophenone) dl -stilbenediimine] ( dl -PHAS), poly[5,5′-methylenebis(2-hydroxyacetophenone)- meso -stilbenediamine] ( meso -PHAS), and poly[5,5′-methylenebis(2-hydroxyacetophenone)azine] (PHAH) have been prepared by polycondensation of 5,5′-methylenebis(2-hydroxyacetophenone (MHA) with ethylenediamine, dl -stilbenediamine meso -stilbenediamine or hydrazine. Each of the polymers has been characterized by elemental microanalysis, infrared and ultraviolet spectroscopy. Their thermogravimetry (TG) and differential thermal analysis (DTA) have been recorded and evaluated. The reduced viscosity of the polymers measured in tetrahydrofuran (THF), dimethylformamide (DMF) and dimethyl sulphoxide (DMSO) was found within 0.202–0.505 dl/g.

Determination of Guanidino Compounds in Serum by Micellar Electrokinetic Capillary Chromatography Using Benzoin as the Derivatizing Reagent

An analytical procedure has been evolved for the determination of seven guanidino compounds; guanidine (G), methylguanidine (MG), guanidinoacetic acid (GAA), guanidinopropionic acid (GPA), guanidinobutyric acid (GBA), arginine (Arg), and guanidinosuccinic acid (GSA) by micellar electrokinetic capillary chromatography (MEKC) within 6 min using benzoin as derivatizing reagent. Sodium dodecyl sulfate (SDS) was used as the micellar medium in a sodium tetraborate (0.1 M) buffer at pH 8.5. Uncoated fused silica capillary was used with an effective length of 39 cm and 75 μm id. Applied voltage was 25 kV and photo diode array detection was set at 228 nm. Linear calibrations obtained from 0.057 to 14.11 μmol/L and limits of detection (LOD) were within 0.019–0.03 μmol/L. The derivatization and separation was repeatable with relative standard deviation (RSD) within 1.9–3.8%. Serum of healthy volunteers and uremic patients was analyzed and amounts found in uremic patients were G 1.98–3.03, MG 1.21–1.79, GAA 3.67–6.09, GPA 1.17–1.37, GBA 1.29–1.46, Arg 9.49–19.17, and GSA 6.83–10.91 μmol/L with RSD (n = 4) within 1.3–4.5%. The amount of guanidino compounds was higher in uremic patients than in healthy volunteers.

Gas Chromatographic Determination of Guanidino Compounds in Uremic Patients Using Glyoxal as Derivatizing Reagent

The guanidino compounds guanidine, methylguanidine, guanidinoacetic acid, guanidinopropionic acid, guanidinobutyric acid and guanidinosuccinic acid were eluted and separated after pre-column derivatization with glyoxal from an HP-5 column (30 m × 0.32 mm i.d.) with film thickness 0.25 µm at an initial column temperature of 100 °C for 2 min, with ramping of 20°C/min up to 250 °C and a nitrogen flow rate of 3 mL/min. Detection was by flame ionization detection. Linear calibrations were observed within 0.1-20.0 µmol/L, with limit of detection within 0.024-0.034 µmol/L for each compound. The separation was repeatable with relative standard deviation (RSD) (n = 6) within 1.2-1.8 and 1.1-1.6% in terms of retention time and peak height/peak area, respectively. The method was applied for the determination of the guanidino compounds from serum of uremic patients (n = 7) and healthy volunteers (n = 8), and amounts were observed within 1.33-11.71 and 0.07-0.39 µmol/L with RSD 1.1-3.5 and 1.1-3.0%, respectively. The results were further supported by the standard addition method.

Synthesis, Characterization and Antibacterial and Antifungal Studies of Schiff base Polymers derived from Methylene bis Cinnamaldehyde

The present study explores the synthesis and characterization of all the compounds via Carbon-Hydrogen-Nitrogen (C.H.N.) analysis with infrared, ultraviolet spectroscopy. Antibacterial and Antifungal studies of these compounds against different antibacterial and antifungal microorganisms gave important findings. Six new Schiff base polymers Poly 4,4-methylene bis(cinnamaldehyde) 1,2-diiminopropane (PMbCPn), Poly 4,4-methylene bis(cinnamaldehyde) 1,3-diiminopropane (PMbCPR), Poly 4,4-methylene bis(cinnamaldehyde) ethylenediimine (PMbCen), Poly 4,4-methylene bis(cinnamaldehyde) 1,2-phenylenediimine (PMbPCPh), Poly 4,4-methylene bis(cinnamaldehyde) Urea (PMbCU), Poly 4,4-methylene bis(cinnamaldehyde) Semicarbazide (PMbCSc), and Poly 4,4-methylene bis(cinnamaldehyde) Thiosemicarbazide (PMbCTSc), were prepared by polycondensing these polymers with methylene bis cinnamaldehyde by a general method. The monomer and Schiff base polymers presented considerable antimicrobial results.

Determination of amino acids in jams, fruits and pharmaceutical preparations by gas chromatography using trifluoroacetylacetone and ethylchloroformate as derivatizing reagents

A gas chromatography (GC)-flame ionization detection procedure was used to determine amino acids in a pharmaceutical preparation (Aminess N tablets), jams (apple, mango, strawberry and mixed fruit), juices (lemon and orange) and a vegetable (kundru). Free amino acids were extracted as aqueous or aqueous–methanol solutions and hydrolyzed by acid treatment with 6 M hydrochloric acid. GC was performed after pre-column derivatization with trifluoroacetylacetone and ethylchloroformate using an HP-5 column (30 m × 0.32 mm id). The complete separation of 19 amino acids was repeatable with a relative standard deviation, in terms of retention time and peak height/peak area, within 3.8%. The limits of detection were in the range 0.1–0.2 μg mL−1. Differences in the concentrations of both free and acid hydrolyzed amino acids were observed in the various jams, fruit juices and vegetables.

Chemical Recycling of Expanded Polystyrene Waste: Synthesis of Novel Functional Polystyrene-Hydrazone Surface for Phenol Removal

Expanded polystyrene (EPS) waste was chemically recycled to a novel functional polystyrene-hydrazone (PSH) surface by acetylation of polystyrene (PS) and then condensation with phenyl hydrazine. The synthesized surface was characterized by the FT-IR and elemental analysis. Synthesized novel functional PSH surface was successfully applied for the treatment of phenol-contaminated industrial wastewater by solid-phase extraction. Multivariant sorption optimization was achieved by factorial design approach. 99.93% of phenol was removed from aqueous solution. FT-IR study showed the involvement of nitrogen of hydrazone moiety of synthesized surface for the uptake of phenol through the hydrogen bonding.

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

Abstract 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=20.41±0.12kJmol-1) nature of the adsorption process. The sorption capacity of PTS was found to be 45.25±0.69mgg-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 five membered chelate formation.