A multi-pumping flow system for acute toxicity bioassay using the Vibrio fischeri bacteria

Autor(es)

Adame, Andressa ^[1] ; Rocha, Fabio R. P. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13400970 Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ANALYTICAL METHODS; v. 6, n. 18, p. 7367-7373, 2014.
• Citações Web of Science: 1

Resumo

A multi-pumping flow system was developed for automation of the acute toxicity bioassay using the Vibrio fischeri bacteria. Solenoid micro-pumps were exploited to improve mixing conditions, and to accomplish the required in-line dilutions of the tested compounds by modifying the sample volume and exploiting the partial overlap between the sample zone and the bacterial suspension. A spiral flow cell, placed at the emission window of a spectrofluorimeter, was used for signal measurements and a lab-made water bath based on the Peltier effect was used for temperature control of the bioassay. A 120 mu L of the bacterial suspension was selected in order to minimize its consumption and, consequently, the costs of the assay. The contact time between the bacterial suspension and sample was reduced to 5 min to increase the sampling throughput and to avoid luminescence fading due to the short bacteria lifetime. The coefficients of variation were estimated at 2.4 and 2.0% (n = 10), in the absence and in the presence of 0.60 mg L-1 Zn(II), respectively. The EC50 values for emerging contaminants (parabens, caffeine, acetaminophen, diclofenac, and salicylic acid) agreed at the 95% confidence level with those obtained with the commercial BioTox (TM) kit performed in a microplate. The proposed flow system is then a simple, fast, robust, and accurate alternative for acute toxicity determination, using low sample and bacterial suspension volumes. Furthermore, it presented other advantages in relation to batch and previously proposed flow-based bioassays, such as in-line osmotic adjustment and sample dilutions, and the evaluation of toxicity kinetics for every assayed sample. (AU)

• Processo FAPESP: 11/23498-9 - Sistemas avançados de análises químicas em fluxo: aplicações nas áreas tecnológica, agronômica e ambiental
• Beneficiário: Elias Ayres Guidetti Zagatto
• Modalidade de apoio: Auxílio à Pesquisa - Temático