Zinc phthalocyanines with fluorinated substituents for direct sensing of carbamate and organophosphate pesticides in water

Abstract

Water pollution by pesticides as the result of intensive agriculture and horticulture has brought many negative consequences to humans and ecosystems. Among others, chemical sensor systems are under intense development for direct pesticide analysis in aqueous samples as a cost effective and simple alternative analytical method. In this work, a set of zinc phthalocyanines is studied in its liquid sensing properties using quartz crystal microbalances. Four different species selected from the two most common organophosphorus and carbamate classes of pesticides are used as test analytes. The phthalocyanines are chemically modified with different fluorinated substituents to increase sensor sensitivity and govern pesticide selectivity in order to create sensors with widely diverging analyte responses. By this means, sensors with a general high sensitivity and selectivity for the two pesticide classes were obtained and detection limits down to 0.03 mg.L-1 could be achieved. The response data of the sensors are analyzed in detail using exploratory multivariate data evaluation methods. The results show that phthalocyanine based sensors are a truly capable platform for chemical analysis systems of aqueous samples.