A novel flow-based procedure for automation of respirometric assays in soils

Autor(es)

Silva, Claudineia R. ^[1] ; Oliveira, Eliezer ^[1] ; Zagatto, Elias A. G. ^[1] ; Henriquez, Camelia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr, Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Talanta; v. 158, p. 14-20, SEP 1 2016.
• Citações Web of Science: 0

Resumo

A flow-based strategy involving a gas-diffusion sampling probe was proposed for evaluating the respiration rate in soils. The amount of CO2 collected after a pre-defined time interval was proportional to the free CO2 released by the soil ecosystem. The 500-mL incubation flasks typically used for soil respirometric assays were adapted and a special cover was designed for connecting a tubular gas diffusion membrane, a fan, and a septum for adding the CO2(g) standards required for calibration. The method relied on the pH-dependent absorbance variations resulting from the CO2 collection. A 1.3 mmol L-1 bromothymol blue solution (pH 7.0) acted as both acceptor and carrier streams. In order to widen the dynamical working range to 0.003-0.2 mmol CO2, two analytical curves were obtained, each related to a different time interval for the CO2 collection. Kinetic curves related to CO2 release by the soil samples were straightforwardly attained. Repeatability and detection limit were estimated as 2.0% and 0.001 mmol CO2 (n=10), and accuracy was assessed in relation to a recommended titrimetric procedure. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/22927-9 - Processos oxidativos avançados na análise química em fluxo.
• Beneficiário: Carla Cripa Crispino Kamogawa
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado