A chemiluminescence flow-based procedure for determination of carbaryl in natural waters exploiting multicommutation and enzymatic reaction

Abstract

Um procedimento empregando detecção quiluminescente para determinação de carbaril em águas naturais utilizando acetilcolinesterase e colina oxidase é descrito. O módulo de análise projetado para implementar o processo de multicomutação controlado por microcomputador foi constituído por cinco válvulas solenóides, duas colunas com enzimas imobilizadas em esferas de vidro e cela de fluxo para detecção de quimiluminescência. Nas melhores condições experimentais foi obtida faixa linear entre 25 a 700 μg L -1 de carbaril. Amostras de água foram fortificadas com carbaril e as recuperações variaram entre 95 e 101%. Limite de detecção e coeficiente de variação foram estimados em 11 μg L -1 (99,7% nível de confiança) e 1,3% (n = 20), respectivamente. Outras características analíticas tais como freqüência de amostragem de 72 determinações por hora, consumo de reagente de 2,1 mg de hexacianoferrato de potássio(III) e 0,069 mg de luminol por determinação, também, foram obtidas.A chemiluminescence procedure for the determination of carbaryl in natural waters using acetylcholinesterase and choline oxidase is described. The flow system designed to implement multicommutation approach controlled by microcomputer comprised five solenoid valves, two columns with immobilized enzymes on controlled pore glass beads and chemiluminometric flow cell. In the best experimental conditions a linear response ranging from 25 to 700 μg L -1 carbaryl was obtained. Water samples were spiked with carbaryl in order to access the accuracy and recoveries between 95 and 101% were obtained for a concentration level ranging from 25 to 100 μg L -1 carbaryl. Detection limit and variation coefficient were estimated as 11 μg L -1 (99.7% confidence level) and 1.3% (n = 20), respectively. Other profitable features such as a sample throughput of 72 determinations per hour, a reagent consumption of 2.1 mg potassium hexacyano ferrate(III) and 0.069 mg luminol per determination were also achieved.

A Glimpse of Recent Developments in Brazilian Analytical Chemistry

“…In the SIA approach, the solution propelling has been carried out using a single pumping channel (Santos and Masini 2007;Abate et al 2006;, thus allowing the use of an automatic syringe (Santos et al 2005b) or a peristaltic pump ). In the MCFIA approach, the peristaltic pump is the most used device for solutions propelling Pires et al 2007; Garcia and Reis 2006;Maruchi and Rocha 2006;Vieira et al 2006;Rodenas-Torralba et al 2005). Recently, the solenoid micro-pump has been introduced as an alternative to peristaltic pump (Lapa et al 2002;Rocha et al 2005;Santos and Masini 2007;Ribeiro et al 2007;Santos and Masini 2007;Carneiro et al 2005), presenting, as advantages, small size and commuting features, and thus permitting its use to replace both peristaltic pump and solenoid valve.…”

Pesticides and Herbicides

“…A chemiluminescence flow-based method for determination of carbaryl in natural waters utilizing multicommutation and enzymatic reaction was reported (Pires et al, 2007). Acetylcholinesterase and choline oxidase were used for the enzymatic reaction.…”