Reusable Enzymatic Strip for Detection of Arsenic

HIGHLIGHTS Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. An enzymatic method has been described by using arsenite oxidase for arsenic detection. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times.

Abstract Arsenic is considered as one of the highly hazardous elements in the environment and a serious carcinogen for the human health. More attention has taken towards the arsenic due to its presence in ground water in India, China, Bangladesh, Inner Mongolia and several other regions of the world. It's been a challenge to remove arsenic due to the lack of its efficient detection approach in the complicated environmental matrix. The proposed method describes an enzymatic method for arsenic determination using arsenite oxidase, which catalyzes the oxidation of arsenite to arsenate. Hence, a colorimetric PVC strip with immobilized arsenite oxidase has been developed to detect the arsenic concentration and also having potential for the field-testing. The influence of the optimal conditions i.e. pH, temperature, storage stability, and reusability of free and immobilized enzyme were evaluated and compared. The results have shown that the stabilities were significantly enhanced compared with free counterpart. Residual activity of the immobilized enzyme was 43% of the initial activity after being recycled 10 times. We approve that this novel low cost immobilized carrier presents a new approach in large scale applications and expected to act as a model for establishment of indigenous arsenic sensor in miniature form.

Desempenho de rótulos de Bopp/papel e de PVC na proteçäo de garrafas de vidro näo retornáveis / Performance of Bopp/paper label and PVC shrink sleeve for the protection of non retornable glass bottles

Avaliou-se a eficiência de rótulos tipo 360 na proteçäo superficial de garrafas de vidro näo-retornáveis para refrigerantes, com capacidade de 250ml, aplicando-se ensaios físicos-mecânicos nas embalagens antes e após tratamento de abrasäo superficial realizado em laboratório. Os rótulos estudados foram: um filme de polipropileno (BOPP) laminado com papel, atualmente utilizado no mercado brasileiro e um rótulo termoencolhível à base de PVC (policloreto de vinila). O desempenho das embalagens previamente rotuladas foi avaliado comparativamente em relaçäo à embalagem sem rótulo e sem abrasäo (garrafa nova, sem uso), por meio dos ensaios de resistência à carga vertical, à pressäo interna e ao impacto. Os resultados mostraram que as garrafas após abrasäo com os 2 tipos de rótulos apresentaram menor à carga vertical e à pressäo interna, da ordem de 5 e 10 por cento, respectivamente, do que as garrafas desprovidas de rótulo e sem abrasäo, enquanto nas garrafas sem rótulo, porém abrasadas as reduçöes foram de 7 por cento para a carga vertical e 30 por cento para pressäo interna. Quanto à resistência