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Issue 3, 2001
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Micro sequential injection: fermentation monitoring of ammonia,glycerol, glucose, and free iron using the novel lab-on-valve system

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Using an integrated lab-on-valve manifold in a microfluidic sequential injection format (μSI), automated sample processing has been developed for off-line and on-line monitoring of small-scale fermentations. Spectrophotometric assays of ammonia, glucose, glycerol, and free iron were downscaled to use micro-quantities of commercial reagents. By monitoring the reaction rate, the response curves in a stopped-flow mode generate linear calibration curves for ammonia [r2 = 1.000 (0.9% SE)], glycerol [r2 = 0.999 (1.1% SE)], glucose [r2 = 0.999 (1.1% SE)], and free iron [r2 = 0.999 (1.5% SE)]. Since sample dilution and reagent quantities are easily adjusted within the programmable SI format, the lab-on-valve system can accommodate samples over a wide concentration range (ammonia: 3–1200 ppm; glycerol: 20–120 ppm; glucose: 35–1000 ppm; and free iron: 80–400 ppm). This work demonstrates the key advantages of miniaturization through the reduction of sample and reagent use, minimizing waste and providing a compact yet reliable instrument. The lab-on-valve manifold uses a universal hardware configuration for all analyses, only requiring changes in software protocol and choice of reagents. All of these features are of particular importance to small-scale experimental fermentation where multiple analyte analyses are needed in real-time using small sample volumes. It is hoped that this first real-life application of the lab-on-valve manifold will serve not only as a model system to downscale assays in a practical fashion, but will also inspire and promote the use of the integrated μSI manifold approach for a wider range of biotechnological applications.

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Publication details

The article was received on 15 Nov 2000, accepted on 05 Jan 2001 and first published on 15 Feb 2001

Article type: Paper
DOI: 10.1039/B009167G
Citation: Analyst, 2001,126, 291-297

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    Micro sequential injection: fermentation monitoring of ammonia, glycerol, glucose, and free iron using the novel lab-on-valve system

    C. Wu, L. Scampavia, J. Ruzicka and B. Zamost, Analyst, 2001, 126, 291
    DOI: 10.1039/B009167G

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