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
Website: @unf

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Classification: Pharmaceutical -> vial

Citations 2

"Flow Injection Spectrophotometric Determination Of Amino-acids Based On An Immobilized Copper(II)-zincon System"
Anal. Chim. Acta 1993 Volume 281, Issue 3 Pages 601-605
L. Lahuerta Zamora, J. Martínez Calatayud

Abstract: The flow injection spectrophotometric determination of different amino acids was carried out by reaction with copper(II) ions entrapped in a polymeric material and filling a packed-bed reactor; the released copper(II), complexed with the amino acid, reacted with zincon in a basic medium producing a blue color that was monitored at 600 nm. The method was applied to determine the contents of different amino acids in pharmaceutical formulations. The calibration graph for glycine was a linear over the range 0.5-20 µg mL-11 with a relative standard deviation of 0.8% (n = 6) at 10 µg mL-1 and a sample throughput of 108 h1-1. The test solution (359 µL) was injected into a stream (2.7 ml/min) of 12.5 mM sodium tetraborate/4.6 mM HCl buffer of pH 9, which was passed through a reactor (13.5 cm x 1.5 mm i.d.; 150-200 µm) containing CuCO3.Cu(OH)2.2H2O and Co (as catalyst) entrapped in AL-100-A polyester resin (Reposa) prepared as described previously (cf. Ibid., 1992, 265, 81). The solution was then mixed with a stream (3.4 ml/min) of 0.1 mM zincon in the same buffer in a 30 cm reaction coil, and the absorbance of the released Cu(II)-zincon complex was measured at 600 nm. The calibration graph was linear from 0.5-20 µg/ml of glycine and the RSD was 0.85% (at 10 mg/ml); hourly throughput was 108 samples. Of the compounds that may be present in pharmaceuticals containing amino-acids, only ascorbic acid interfered (at 10 mg/ml of amino-acid and up to 500 mg/ml of interferent). The method was used successfully to determine glycine in phial contents and tablets, with RSD of 1 and 2.9%, respectively. The method was also applied in the determination of proline, histidine, alanine, leucine and phenylalanine (calibration data given).
Amino Acids l-Proline Histidine Alanine Leucine Phenylalanine Spectrophotometry Interferences Catalysis Solid phase reagent Resin Immobilized reagent

"The Determination Of Small Quantities Of Water In Single Vials Of Pharmaceutical Products By Flow Injection Analysis"
J. Pharm. Biomed. Anal. 1990 Volume 8, Issue 8-12 Pages 995-998
M. S. Bloomfield*, G. E. Williams and R. Jones

Abstract: The flow injection system, consisting of a peristaltic pump, an injection point, PTFE reaction tubing (120 cm x 0.5 mm) and a spectrophotometer was used for determination of water in single vials of lyophilized pharmaceuticals after reconstitution in a suitable anhydrous solvent. For determination of water in an Acyclovir IV 250 mg vial, the contents of the vial were reconstituted with an anhydrous solution of ethanediol in methanol. The solution was transferred to autosampler vials and sealed in. Portions (10 µL) of the solution were injected into a stream (1.5 mL min-1) of Karl Fischer reagent (0.625 mg mL-1) and the absorption was measured at 625 nm. A methanolic ethanediol blank was also run. Response was rectilnear up to 0.28% v/v of water. Recovery was satisfactory.
Water Karl Fischer analysis Spectrophotometry