Turbidimetric and photometric determination of total tannins in tea using a micro-flow-batch analyzer

Both turbidimetric and photometric determinations of total tannins in samples of green and black tea, using a micro-flow-batch analyzer (μFBA) were studied. The miniaturized system was formed using photocurable urethane-acrylate resin and ultraviolet lithography technique. The turbidimetric method w...

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Detalles Bibliográficos
Autores: Lima, Marcelo B., Andrade, Stéfani I. E., Harding, David P., Pistonesi, Marcelo Fabian, Fernández Band, Beatriz Susana, Araújo, Mário C.U.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/58632
Acceso en línea:http://hdl.handle.net/11336/58632
Access Level:acceso abierto
Palabra clave:FLOW-BATCH SYSTEM
GREEN AND BLACK TEA
MICROFABRICATION
PHOTOMETRIC DETERMINATION
TANNINS
TURBIDIMETRIC DETERMINATION
URETHANE-ACRYLATE
https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
Descripción
Sumario:Both turbidimetric and photometric determinations of total tannins in samples of green and black tea, using a micro-flow-batch analyzer (μFBA) were studied. The miniaturized system was formed using photocurable urethane-acrylate resin and ultraviolet lithography technique. The turbidimetric method was based on the precipitation reaction of Cu (II) with tannins in acetate medium at a pH of 4.5. The photometric method was based on the complexation reaction of tannins with ferrous tartrate. The turbidimetric μFBA was able to test 200 samples per hour. The photometric μFBA allowed 300 analyses per hour, generating 136 μL of residue per analysis. The paired t test, at a 95% confidence level, showed no statistically significant differences between results obtained by both methods and the reference method. The urethane-acrylate μFBA maintained satisfactory physical and chemical properties, and represents an improvement over conventional flow-batch analyzer.

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