Enzymatic chemiluminescent assay of glucose by sequential-injection analysis with soluble enzyme and on-line sample dilution

• Published in: Analytica chimica acta Vol. 572; no. 1; pp. 140 - 147
• Main Authors: Economou, Anastasios, Panoutsou, Polyxeni, Themelis, Demetrius G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 14.07.2006; Elsevier
• Subjects: Analytical chemistry; Chemical and thermal methods; Chemiluminescence; Chemistry; Exact sciences and technology; General, instrumentation; Glucose; Glucose oxidase; On-line sample dilution; Sequential-injection analysis; Glucose oxidase; Chemiluminescence; Glucose; Sequential-injection analysis; On-line sample dilution; Chemical analysis; Hydrogen peroxide; Instrumentation; Stopped flow method; Reversed flow; Sequential method; Cobalt II; Detection limit; Luminol; Sampling; Measurement error; Variation coefficient; Catalytic reaction; Enzyme; Automatic processing; Honey; Enzymatic method; Dilution; Sample cell; Relative error; Oxidoreductases; Catalyst; Enzymatic reaction
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2006.05.023

This work reports a sequential-injection analysis (SIA) method for the enzymatic assay of glucose with soluble glucose oxidase (GOD) and on-line sample dilution with chemiluminescence (CL) detection. A zone of sample was aspirated in the holding coil of the SIA manifold and, if necessary, was diluted on-line by means of an auxiliary dilution conduit. Then, a zone of GOD was aspirated adjacent to the sample zone and a stopped-flow period was applied to allow the enzymatic reaction to proceed with production of hydrogen peroxide. Then, zones of a catalyst (Co(II) solution) and alkaline luminol were aspirated into the holding coil. Finally, the flow was reversed and the stacked zones were sent to a flow-cell located in front of a photomultiplier tube (PMT) that monitored the CL intensity. The linear dynamic range was 1 × 10 −5–1 × 10 −3 mol L −1 glucose, the coefficient of variation at 8 × 10 −5 mol L −1 of glucose was s r = 3.1% ( n = 8), the limit of detection at the 3 σ level was c L = 1 × 10 −6 mol L −1 and the sampling frequency was 28 h −1. With on-line dilution by a factor of 1/200, the linear range could be extended up to 0.2 mol L −1 glucose. The advantages of the proposed method are the simple manifold and instrumentation used, the scope for automated on-line dilution, the low consumption of sample and reagents and the elimination of enzyme immobilisation procedures. The method was applied to the analysis of commercial drinks and honey with percent relative errors in glucose determination in the range 100 ± 6.1%.