Biomedical subjects

M Y Khuhawar

Publications and source records attributed to M Y Khuhawar.

14 recordsLinked to original sources

PubMed2006

Sawdust--a green and economical sorbent for the removal of cadmium (II) ions.

The ability of sawdust (treated and untreated) waste, a waste material derived from the commercial processing of cedrus deodar wood for furniture production, to remove/preconcentrate Cd(II) ions from aqueous solution was determined. Sorption was found to be rapid (approximately 97% within 8 min). The binding of metal ions was found to be pH dependent, optimal sorption accruing at around pH 4-8. Potentiometric titrations of sawdust revealed two distinct pK(a) values, the first having the value similar to carboxylic groups (3.3-4.8) and second comparable with that of amines (8.53-10.2) with the densities 1.99 x 10(-4) and 7.94 x 10(-5), respectively. Retained Cd(II) ions were eluted with 5 ml of 0.1 mol l(-1) HCl. Detection limit of 0.016 microg ml(-1) was achieved with enrichment factors of 120. Recovery was quantitative using sample volume of 600 ml. The Langmuir and D-R isotherm equations were used to describe partitioning behavior for the system at different temperatures. Kinetic and thermodynamic behavior of sawdust for Cd(II) ions removal was also studied.

Adsorption↗

PubMed2006

Capillary gas chromatographic determination of phenylpropanolamine in pharmaceutical preparation.

Analytical procedure has been developed for the gas chromatographic determination of phenylpropanolamine (PPA) using trifluoroacetylacetone (FAA) as derivatizing reagent. Elution is carried out from the column HP-5 (30 mx0.32 mm i.d.) with film thickness 0.25 microm at initial column temperature 70 degrees C for 5 min, followed by heating rate 10 degrees C/min up to 120 degrees C. Injection port temperature was maintained at 270 degrees C. Nitrogen flow rate was 2 ml/min and detection was by FID. The linear calibration curve was obtained with 30-150 microg/ml PPA with detection limit of 6.0 microg/ml. The method was used for the determination of PPA from Sinutab and Tavegyl-D tablets. The relative standard deviation (R.S.D.) for the analysis of pharmaceutical preparation was obtained within 0.4-0.9%.

Calibration↗

PubMed2006

Spectrophotometric and liquid chromatographic determination of dopamine from pharmaceutical preparations using acetyl acetone as derivatizing reagent.

Dopamine (DA) has been determined by spectrophotometry and by liquid chromatography as derivatives of acetylacetone (AA). The liquid chromatography of DA was carried out in the presence of hydroxyproline (HP), octopamine (OP) and tyramine (TY). The separation was obtained from Phenomenex C-18 column 5 pm (150 x 4.6 mm id) by isocratic elution with methanol: acetonitrile: water (45: 6: 49 v/v/v), UV detection was at 320 nm. Linear calibration curves were obtained for each with 2.5-40.0 microgml(-1) with detection limits in the range 1.8-80 ng injection(-1) (10 microl). The dopamine was determined in pharmaceutical preparations with coefficient of variation (CV) within 0.7-1.5%.

Calibration↗

PubMed2005

Preconcentration and separation of Cr(III) and Cr(VI) using sawdust as a sorbent.

A simple, inexpensive method based on solid-phase extraction (SPE) on sawdust from Cedrus deodera has been developed for speciation of Cr(III) and Cr(VI) in environmental water samples. Because different exchange capacities were observed for the two forms of chromium at different pH-Cr(III) was selectively retained at pH 3 to 4 whereas Cr(VI) was retained at pH 1-complete separation of the two forms of chromium is possible. Retained species were eluted with 2.5 mL 0.1 mol L(-1) HCl and 0.1 mol L(-1) NaOH. Detection limits of 0.05 and 0.04 microg mL(-1) were achieved for Cr(III) and Cr(VI), respectively, with enrichment factors of 100 and 80. Recovery was quantitative using 250 mL sample volume for Cr(III) and 200 mL for Cr(VI). Different kinetic and thermodynamic properties that affect sorption of the chromium species on the sawdust were also determined. Metal ion concentration was measured as the Cr(VI)-diphenylcarbazide complex by UV-visible spectroscopy. The method was successfully applied for speciation of chromium in environmental and industrial water samples.

Adsorption↗

PubMed2005

Enrichment of Pb(II) ions using phthalic acid functionalized XAD-16 resin as a sorbent.

A simple and reliable method has been developed using polymeric material containing phthalic acid as a chelating agent to concentrate ultratrace amounts of lead ions in aqueous solutions. After characterization by CHN, IR, and thermal studies, the static and dynamic sorption behavior of Pb(II) ions onto new synthetic resin has been investigated. The sorption has been optimized with respect to pH, shaking speed, and contact time between the two phases. Maximum sorption is achieved from solution of pH 5-8 after 10 min agitation time. The lowest concentration for quantitative recovery is 5.8 ng cm(-3) with a preconcentration factor of approximately 850. The kinetics of sorption follows the first-order rate equation with the rate constant k=0.58+/-0.04 min(-1). The variation of the equilibrium constant K(c) with temperature between 10 and 50 degrees C yields values of DeltaH, 52.4+/-1.65 kJmol(-1), DeltaS, 186+/-5.21 Jmol(-1)K(-1), and DeltaG(303K), -4.15+/-0.002 kJmol(-1). The sorption data of Pb(II) ions in the concentration range from 2.41x10(-6) to 1.44x10(-4) molL(-1) follows the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms at all temperatures investigated. The sorption of Pb(II) ions onto synthesized resin in the presence of common anions and cations has also been measured. The possible sorption mechanism of Pb(II) ions onto phthalic acid modified XAD-16 is also discussed. The sorption procedure is utilized to preconcentrate Pb(II) ions prior to their determination in automobile exhaust particulates by atomic absorption spectrometry using direct and standard addition methods.

Journal Article↗

PubMed2004

Liquid chromatography of uranium complexes of tetradentate Schiff bases.

Dioxouranium together with copper(II), nickel(II) and iron(II) were extracted in chloroform as complexes of bis(salicylaldehyde)-dl-stilbenediimine (dl-H2SA2S) or bis(salicylaldehyde)-meso-stilbenediimine (meso-H2SA2S), and separated by liquid chromatography with UV detection. The linear calibration range and detection limits were 40 - 200 ng and 10 ng/injection for each metal ion. The method was applied to the determination of uranium from mineral ore samples at concentrations of 30 - 700 microg/g with coefficients of variation from 3.6 to 5.5%. The relative elution of dioxouranium complexes of different Schiff bases was examined from reversed-phase HPLC; the substitution of methyl and phenyl groups at the bridge position enhanced the column retention of uranyl complexes.

Journal Article↗

PubMed2003

Liquid chromatographic determination of gamma-aminobutyric acid in cerebrospinal fluid using 2-hydroxynaphthaldehyde as derivatizing reagent.

gamma Aminobutyric acid (GABA) was determined by precolumn derivatization with 2-hydroxynaphthaldehyde and elution was made using Phenomenex C(18), 5 microm column with methanol: water (62:38 v/v) and UV detection at 330 nm. In a mixture containing glycine, l-lysine and tyramine GABA separated completely. A number of amines and amino acids tested did not affect the response of GABA. A linear calibration curve was obtained for GABA in the range of 1.2-28.0 microg/ml with detection limit of 2.8 ng/injection (5 microl). The method was used for the determination of GABA in cerebral spinal fluid (CSF) samples and gave results of 19.0 to 22.4 microg/m1 with coefficient of variation 2.4%

Aldehydes↗

PubMed2002

Gas and liquid chromatography of metal chelates of pentamethylene dithiocarbamate.

Capillary GC and HPLC of metal chelates of pentamethylene dithiocarbamate were examined. Copper(II), nickel(II), cobalt(III), iron(III), manganese(II) and chromium(III) chelates formed in slightly acidic media (pH 5) were extracted in methyl isobutyl ketone or chloroform. Capillary GC elution and separation was carried out on methylsilicone DB-1 column (25 m x 0.2 mm I.D.) with film thickness 0.25 microm. Electron-capture detection was used. Elution was carried at initial column temperature 200 degrees C with an increment at a rate of 5 degrees C/min up to 250 degrees C and maximum temperature was maintained for 10 min. Symmetrical peaks with baseline separation were obtained with the metal chelates investigated with linear calibration range between 5 and 25 microg/ml for each metal ion and detection limits in the range of 0.5-6.0 microg/ml corresponding to 27-333 pg of metal ion reaching to the detector. HPLC separation was carried out from LiChrosorb ODS, 5 microm column and complexes eluted with methanol-water-1 mM sodium acetate (70:28:2, v/v) with a flow-rate of 1.2 ml/ml. UV detection was at 260 nm. The detection limits obtained were in the range 2-6 microg/ml. The methods were applied to the determination of metal ions in canal water and coal samples with RSD values within 4.15%. The results when compared with a standard flame atomic absorption spectrophotometric method and revealed no significant difference.

Chelating Agents↗

PubMed2002

Liquid chromatographic determination of isoniazid, pyrazinamide and rifampicin from pharmaceutical preparations and blood.

Isoniazid (IN), pyrazinamide (Pz) and rifampicin (Rf) are separated on YMC-ODS column. IN was derivatized with 2-fluorene-carboxaldehyde (FA). The separation was achieved using ethanol-chloroform-acetonitrile water by isocratic elution and detected at 337 nm. The detection limits were 0.11 ng, 0.2 ng and 13 ng/injection (5 microl) for IN, Pz and Rf, respectively. The method of analysis was applied to the pharmaceutical preparations and in the blood samples of the patients suffering from tuberculosis after undergoing chemotherapy with IN, Pz and Rf. The amounts quantitated in blood showed 0.97 to 1.58 microg/ml IN, 3.44 to 4.09 microg/ml Pz and 1.98 to 3.5 microg/ml Rf with coefficient of variations 0.8-1.8%, 0.9-1.3% and 0.8-2.1%, respectively.

Antitubercular Agents↗

PubMed2001

Polyamines as cancer markers: applicable separation methods.

Spermine, spermidine, putrescine and cadaverine are aliphatic amines widely spread in the human body. Their concentrations together with their acetyl conjugates increase significantly in the biological fluids and the affected tissues of cancer patients. Their concentrations decrease with the improvement in the patient's condition on multiple therapy. Various chromatographic techniques are frequently used in monitoring concentrations of di- and polyamines in cancer. Among these techniques, thin-layer chromatography and liquid chromatography using pre- or postcolumn derivatization, separating on a reversed-phase or an ion-exchange column are the most commonly used. Besides, high-resolution capillary column gas chromatography (GC) is increasingly used over packed column GC, and in recent years, capillary zone electrophoresis has also gained some importance in polyamine determinations. The review examines the prospects and the limitations of polyamines as cancer markers using chromatographic and electrophoretic techniques.

Biogenic Polyamines↗

PubMed2001

HPLC determination of phenylpropanolamine in pharmaceutical preparations using 4-dimethylaminobenzaldehyde as a derivatizing reagent.

A method is described for the high performance liquid chromatographic (HPLC) determination of phenylpropanolamine (PPA) based on precolumn derivatization with 4-dimethylaminobenzaldehyde (DAB) and elution from phenomenex C-18 column with methanol-water and detection by spectrophotometry at 418 nm. Linear calibration was obtained with 9.4--46.9 microg ml(-1) with a detection limit of 4.7 ng ml(-1). Vitamin B(12) and rifampicin when present together with PPA separated completely and could be determined simultaneously. PPA was determined in pharmaceutical preparations with a relative standard deviation of 0.6--1.6%.

Chromatography, High Pressure Liquid↗

PubMed1999

Capillary gas chromatographic determination of putrescine and cadaverine in serum of cancer patients using trifluoroacetylacetone as derivatizing reagent.

Trifluoroacetylacetone (FAA) derivatives of 1,4-diaminobutane (putrescine) (Pu) and 1,5-diaminopentane (cadaverine) (CA) were prepared and characterized by elemental microanalysis, IR, and mass spectrometry. Diamine derivatives were eluted from capillary gas chromatographic (CGC) column BP1 (12 m x 0.22 mm I.D.) or BP5 (50 m x 0.22 mm) with layer thickness 0.25 microm, using nitrogen as a carrier gas and flame ionization detection (FID). A solvent extraction procedure was developed for the extraction of Pu and CA from aqueous solution with a linear calibration range 0-20 microg/0.2 ml of extract with a detection limit of 0.5-0.6 ng/injection. The method was applied for the determination of Pu and CA in the serum of five cancer patients before and after radiotherapy. The serum of two healthy persons was also analyzed for Pu and CA contents. Pu and CA concentrations were found within the range 1.16-3.96 microg/ml and 0.88-1.46 microg/ml in cancer patients as compared to 0.11-0.16 microg/ml and 0.06-0.075 microg/ml respectively in healthy persons with a coefficient of variation (CV) within 0.62-5.47%. Pu and CA concentrations decreased on radiotherapy in cancer patients, but were much higher than in healthy persons.

Cadaverine↗

PubMed1998

High performance liquid chromatographic determination of isoniazid, pyrazinamide and rifampicin in pharmaceutical preparations.

lsoniazid (IS) individually or in the presence of pyrazinamide and rifampicin has been determined by high performance liquid chromatography (HPLC) after derivatization with 6-methyl-2-pyridinecarboxaldehyde. Pyrazinamide and rifampicin separate completely from isoniazid derivative and are determined simultaneously. The chromatography is carried out from YMC-ODS column with elution with methanol: water: isopropanol: acetonitrile: sodium acetate (1 mM) 51:42:3:2:2: v/v/v/v/v/) with flow rate 1.7 ml/min and UV detection at 333 nm. The method is applied for the analysis of Isoniazid B.P Rambuzid and Myrene-p tablets.

Journal Article↗

PubMed1997

High-performance liquid chromatographic determination of cisplatin as platinum(II) in a pharmaceutical preparation and blood samples of cancer patients.

An high-performance liquid chromatographic (HPLC) method has been developed for the determination of cisplatin, based on precolumn derivatization of platinum(II) with bis(salicylaldehyde)tetramethylethylenediimine, extraction in chloroform and elution from a 3 microm Hypersil ODS column with methanol-acetonitrile-water as mobile phase and detection at 254 nm. Copper(II), iron(II), nickel(II), palladium(II), dioxouranium(IV) separated completely and did not affect the determination of platinum(II). The method was applied for the determination of cisplatin as platinum(II) in a pharmaceutical preparation and in blood samples of cancer patients after infusion of cisplatin.

Antineoplastic Agents↗