University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Mohammed Masoom

Abbrev:
Masoom, M.
Other Names:
Mohammed Masoom Kassi
Address:
Institute of Biochemistry, University of Baluchistan, Quetta Pakistan
Phone:
+354-525-4463
Fax:
+354-525-4071
Email:
mmasson@hi.is

Citations 7

"4-Amino-1-naphthylphosphate As A Substrate For The Amperometric Detection Of Alkaline Phosphatase Activity And Its Application For Immunoassay"
Talanta 2004 Volume 64, Issue 1 Pages 174-180
Már Másson, Ögmundur V. Rúnarsson, Fjalar Jóhannson and Masuo Aizawa

Abstract: Immunosensors and biochemical array detection systems based on electrochemical transducers have many advantages such as low detection limit, fast response, simple design and ease of miniaturization. However, further development of such sensors will depend on the availability of suitable substrates that can be converted by a labeling enzyme to an electrochemically active product. Here, we report the synthesis of 4-amino-1-naphthylphosphate and it's application as a new substrate for alkaline phosphatase. The electrochemical and enzymatic properties of this compound were investigated and compared with the properties of other aromatic 1,4-dihydroxy and 1,4-hydroxy-amine derivatives. The product of the enzyme reaction was 4-aminonaphthol, which was rapidly converted in the presences of air to 1,4-iminonaphthoquinone. This compound could then be detected in an amperometric flow injection assay (AFIA) with -200 mV versus Ag/AgCl potential application. The analytical range for mouse IgG, in an alkaline phosphatase amplified sandwich immunoassay with amperometric detection, was 0.01-100 µg mL-1.

"Automated Flow Injection Method For The Assay Of Xanthine-oxidase Activity"
J. Chem. Soc. Pak. 1989 Volume 11, Issue 3 Pages 210-213
Masoom, M. (SFS)

Abstract: An automated flow injection system is described, based on the principle of stopped flow-merging zones, for the estimation of xanthine oxidase activity. The method is based on monitoring spectrophotometrically the production of uric acid at 290 nm. Hypoxanthine is used as a substrate for the enzyme. A good linear calibration with a correlation coefficient of 0.9928 for xanthine oxidase standards (0-100 U!L) is obtained. The precision is 2.0% and sample throughput is 35-40/h.
Enzyme, xanthine oxidase Uric acid Spectrophotometry Automation Stopped-flow Merging zones

"Automated Fluorimetric Determination Of Creatine Using Flow Injection Analysis"
J. Chem. Soc. Pak. 1989 Volume 11, Issue 1 Pages 32-36
Masoom, M.

Abstract: The sample was analyzed by computer-controlled stopped-flow flow injection analysis in water as carrier stream (2.5 mL min-1), with mixing with aqueous ethanolic 10% ninhydrin and aqueous ethanolic 10% KOH and fluorimetric detection at 500 nm (excitation at 400 nm). A calibration graph based on the rate of formation of product was rectilinear for up to 0.1 mg L-1 of creatine. The within-batch coefficient of variation at 40 µg L-1 was 2.3% (n = 10). The method can be applied to biological fluids.
Creatine Biological fluid Fluorescence Automation Computer Stopped-flow

"Flow Injection Analysis - A Superior Alternative To Air-segmented Continuous-flow Analysis"
J. Chem. Soc. Pak. 1988 Volume 10, Issue 2 Pages 269-282
Masoom, M.; Townshend, Alan (SFS)

Abstract: A review with 85 references.
Sample preparation Extraction Merging zones Method comparison Reverse Review Stopped-flow

"Automated Spectrophotometric Flow Injection Assay Of Alkaline Phosphatase"
Anal. Lett. 1988 Volume 21, Issue 12 Pages 2381-2388
Masoom, M.

Abstract: Enzyme standard solution (0 to 250 iu l-1), sample (20 µL) and substrate solution (6 mM 4-nitrophenyl phosphate; 20 µL) were simultaneously injected into separate streams of 0.1 M diethanolamine buffer (pH 9.8), each pumped equally to give an overall flow rate of 2.5 mL min-1. Flow-line tube diameter was 0.5 mm and the distance from the confluence point to the detector was 50 cm, inclusive of a packed reactor (2.5 cm x 2.5 mm) containing glass beads (0.5 to 0.75 mm). Absorbance was monitored at 405 nm (based on the rate of formation of 4-nitrophenol from the substrate). Calibration graphs were rectilinear over the range studied. Within-batch precision was 1.8%; total analysis time was 85 s per sample.
Enzyme, alkaline phosphatase Blood Plasma Spectrophotometry Computer Glass beads Indirect

"Immobilized Enzymes In Clinical And Biochemical Analysis. Applications To The Simultaneous Determination Of Acetylcholine And Choline And To The Determination Of Lipids"
Anal. Chim. Acta 1988 Volume 214, Issue 1-2 Pages 173-186
M. Masoom

Abstract: A flow injection analysis system was used with a 10 µL sample-injection loop, one or more immobilized-enzyme reactor columns and an amperometric (for choline or acetylcholine) or a commercial (HPLC) potentiometric detector (for lipids). In the former system, acetylcholinesterase and choline oxidase were immobilized by glutaraldehyde cross-linking to controlled-pore glass and packed into columns (3 cm x 2.5 mm) that were operated at 25°C. The amperometric detector consisted of two Pt electrodes (6 mm x 3 mm) sandwiched between Perspex sheets and separated by a 1-mm-thick sheet of silicone rubber, and the carrier stream (0.5 mL min-1) was 0.1 M phosphate buffer adjusted to pH 8.2. Rectilinear calibration graphs for 10 to 100 µM-choline and -acetylcholine were obtained. For determination of phospholipids, the appropriate phospholipase and glycerol-3-phosphate oxidase were used in the included reactor columns with a carrier stream (1.5 mL min-1) of pH 7.0 containing 20 mM barbitone sodium(I), or a column of co-immobilized phosphatase - choline oxidase was used with a buffered carrier stream of 0.1 M Tris (pH 7.5) or 20 mM I (pH 6.5), Triton X-100 (0.2 or 0.3%) and 0.4 mM ZnCl2 or 30 mM CaCl2. Calibration graphs for phosphatidylcholine were rectilinear for 1 to 10 mM or 50 to 800 mg l-1.
Choline Acetylcholine Phospholipids Blood Amperometry Biochemical analysis Clinical analysis Ion exchange Potentiometry Electrode Controlled pore glass Immobilized enzyme Surfactant Triton X Simultaneous analysis

"Determination Of Phosphatidylcholine In A Flow Injection System Using Immobilized Enzyme Reactors"
Anal. Biochem. 1990 Volume 187, Issue 2 Pages 240-245
Mohammed Masoom, Rita Roberti and Luciano Binaglia

Abstract: Two alternative procedures are described for the quantitative determination of phosphatidylcholine in a flow injection system utilizing immobilized enzymes. Phospholipase C from Bacillus cereus and phospholipase D from cabbage were covalently bound to the surface of controlled-pore glass beads and the enzyme-derivatized beads were packed in small columns. In the first procedure, the phospholipase C column was connected with a second column containing coimmobilized alkaline phosphatase and choline oxidase. In the alternative procedure, the column packed with immobilized phospholipase D was connected with a column packed with immobilized choline oxidase. The hydrogen peroxide produced through the action of choline oxidase in both flow injection systems was detected amperometrically. Both procedures are suitable for an accurate and rapid quantitation of phosphatidylcholine. The sensitivity of the method based on phospholipase C and alkaline phosphatase is higher than that using phospholipase D. Quantitation of phosphatidylcholine at the nanomole level can be easily obtained using the first methodology. Membrane lipids were extracted from brain by the method of Folch et al. (J. Biol. Chem., 1957, 226, 497) and dissolved in CHCl3 - methanol (2:1). The solution was evaporated in vacuo and the lipid residue was dissolved in 0.1 M Tris - HCl buffer of pH 7.5 containing 0.3% of Triton X-100 and 0.4 mM ZnCl2. The suspension was injected into a stream (pH 6.5) of 30 mM CaCl2 containing 0.3% of Triton X-100 and 20 mM diethylbarbitone and passed through columns of phospholipase C immobilized on glass beads and of alkaline phosphatase and choline oxidase immobilized on glass beads before electrochemical detection with a vitreous-carbon electrode at +0.6 V. The calibration graph was rectilinear for 0.05 to 2 mM phosphatidylcholine. The sensitivity was higher than that of a flow injection method using phospholipase D.
Phosphatidylcholine Amperometry Electrochemical analysis Electrode Immobilized enzyme Enzyme Column Controlled pore glass Sensitivity Membrane Buffer pH Triton X Glass beads Surfactant