Glucose spectrophotometric determination

J.M.T. Carneiro, A.C.B. Dias, E.A.G. Zagatto, J.L.M. Santos, J.L.F.C. Lima, An improved sampling approach in multi-pumping flow systems applied to the spectrophotometric determination of glucose and fructose in syrups, Anal. Chim. Acta 531 (2005) 279. 

The feasibility of the innovation for saving expensive reagents was demonstrated by the spectrophotometric determination of glucose in serum [8] by an enzymatic method using glucosidase and peroxidase. 

Analytical methods. After the reactor operation the fibers were cut into 10 cm segments and dried in an oven at 90°C for 72 hours. The dry mass density was obtained by taking the difference between the dry mass of the cut fiber and that of an empty one of equivalent length. This difference corresponds to the biomass accumulated in the interstitial space between the inner and outer fibers. Glucose was determined by glucose analyzer (YSI model 23 A, Yellow Springs, OH) and rifamycin B was measured spectrophotometrically at A25 nm. 

J. Toei and N. Baba, New Type Valve for Flow Injection Analysis. 1. Application to Stopped-Flow Spectrophotometric Determination of Glucose [in Japanese]. Bunseki Kagaku, 35 (1985) 411. 

G. J. Moody, G. S. Sanghera, and J. D. R. Thomas, Modified Platinum Wire Glucose Oxidase Amperometric Electrode. Analyst, 111 (1986) 1235. M. A. Koupparis and P. I. Anagnostopoulou, Automated Flow Injection Spectrophotometric Determination of Zinc Using Zincon Applications to Analysis of Waters, Alloys and Insulin Formations. Analyst, 111 (1986) 1311. 

The enzyme-entrapped polypyrrole was rinsed, and measurement of entrapped enzyme activity was performed. Enzyme activity of a PP-GOD and PP-ADH membranes were spectrophotometrically determined. A PP-GOD membrane was soaked in a solution which contained 90 mM glucose, 7 per-... 

It should be noted that when we used methods of measurement needing inorganic reference materials for calibration (such as flame photometry or atomic absorption spectrometry) the uncertainty due to the reference materials was considerably lower than that due to the photometric device. On the contrary, when we used a clinical reference material certified for its glucose concentration with a 10% (rel) uncertainty, this uncertainty exceeded twice the uncertainty due to the spec-trophotometric device. When we determined Mg by a spectrophotometric method with Titan Yellow, we found that the uncertainty due to the reference material was approximately twice that due the device, as we used a very accurate spectrophotometer. 

The coupled reactions of isomerase, mutarotase and GOD should be applicable to assay fructose, but a sensor using this sequence has not been described to date. An FIA manifold containing an enzyme reactor with glucose isomerase and mutarotase for the determination of fructose has been developed by Olsson (1987). The glucose formed was measured spectrophotometrically. 

Enzymes in their natural environment have been used as "solid reagents" and Saccharomyces cerevisae is a good example [118]. Enzyme cartridges have also been used, as demonstrated by the determination of glucose in plasma using flow injection manifolds with spectrophotometric and chemiluminometric detection and an in-line immobilised enzyme coil [119]. The coil consisted of glucose oxidase covalently bound to the inner surface of a nylon tube (25 cm long, 1.0 mm i.d.) which was coiled into a cylindrical acrylic exoskeleton. 

P.J. Worsfold, J. Farrelly, M.S. Matharu, A comparison of spectrophotometric and chemiluminescence methods for the determination of blood glucose by flow injection analysis, Anal. Chim. Acta 164 (1985) 103. 

---