Construção de uma cela de fluxo de longo caminho óptico para medidas espectrofotométricas

• Autor(a) principal: Melchert,Wanessa Roberto
• Data de Publicação: 2008
• Outros Autores: Rocha,Fábio R. P., Raimundo Jr.,Ivo M., Reis,Boaventura F.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Química Nova (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422008000200042
• topic: long pathlength spectrophotometry; flow analysis; liquid core waveguide

A simple and low-cost flow cell with 30 cm optical path for spectrophotometric measurements is described. It presents desirable characteristics such as low attenuation of the radiation beam and internal volume (75 µL) comparable to that of a 1-cm conventional cell (80 µL). Despite the increase in optical path, the effect on sample dispersion was also similar to that attained in the commercial cell. The performance of the cell was assessed by the determination of phosphate based on the molybdenum blue method, yielding a linear response range between 0.05 and 0.8 mg L-1 phosphorus (r=0.999). The increase in sensitivity (30.4-fold) in comparison with that obtained with a conventional 1-cm flow cell agreed with that estimated by the Lambert-Beer law.