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: Plant -> cassava -> leaves

Citations 2

"Immobilization Of Linamarase And Its Use In The Determination Of Bound Cyanide In Cassava Using Flow Injection Analysis"
Anal. Biochem. 1988 Volume 172, Issue 1 Pages 89-95
D. Narinesingh*, D. Jaipersad and I. Chang-Yen

Abstract: β-Glucosidase was immobilized (details given) on 2-fluoro-N-methylpyridinium-activated Fractogel support; the gel was washed and packed in nylon columns (5 cm x 2 mm) for use in flow injection analysis. Cassava leaves or tubers were extracted with H3PO4, the extracts were filtered under vacuum and the filtrates were adjusted to pH 7.2 with 1 M NaOH and centrifuged at 3000 rpm for 5 min. Portions (90 µl) of the supernatant solution were injected into the flow injection system, at 30°, and passed (0.33 mL min-1) into the reactor column, or a blank column to correct for free CN-. The solution were then mixed with picrate reagent of pH 10.8 and passed through a coil at 85°C and the absorbance of the complex formed was measured at 525 nm. The calibration graph was rectilinear, for both free CN- and CN- liberated from linamarin, from 1 to 10 mM; the detection limit was 67 ppm. Interference from glucose and acetone was negligible. Extracts from the tubers (cortex and parenchyma) and leaves of Manihot esculenta Crantz (cassava) were analyzed for their releasable cyanide content using flow injection analysis incorporating an immobilized linamarase bioreactor. Linamarase was immobilized under very mild conditions to an activated 2-fluoro-N-methylpyridinium Fractogel support. The released cyanide, which was monitored spectrophotometrically at 525 nm using an alkaline picrate reagent, was found to be highest in the cortex and lowest in the parenchyma.
Cyanide Sample preparation Spectrophotometry Interferences Heated reaction Immobilized enzyme Interface

"Turbidimetric Determination Of Potassium By Flow Injection Analysis"
Anal. Lett. 1994 Volume 27, Issue 8 Pages 1625-1636
De Oliveira Torres, J.R.;Tubino, M.

Abstract: The FIA system comprised two aqueous 2% glycerol carrier solution (1.2 ml/min) into which 400 µL of a 3% sodium tetraphenylboron solution (prep. described) and 400 µL of sample solution containing 2% glycerol were separately introduced. The carrier streams were mixed in a reaction bobbin (1.5 m x 1 mm i.d.) of polyethylene tubing and the absorbance was read at 420 nm. To enhance sensitivity to 1 µg/ml, a stream of aqueous KCl solution (1.5-3 µg/ml; 0.36 ml/min) was introduced into the aqueous glycerol carrier solution The calibration graphs were linear for up to 20 µg/ml of K, the detection limit was ~1 µg/ml and the RSD were ~1%. The sampling rate was 60/h. The method was applied to plant leaves (chicory, cabbage, kale), mineral water and serum rehydration solution; the results agreed well with those obtained by flame photometry (plants) or with the expected values.
Potassium Turbidimetry