Technique for rapid detection of phthalates in water and beverages
AuthorsZia, Asif I.
Rahman, Mohammed Syaifudin Abdul
Mukhopadhyay, Subhas Chandra
Al-Bahadly, Ibrahim H.
Gooneratne, Chinthaka Pasan
KAUST DepartmentSensing, Magnetism and Microsystems Lab
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
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AbstractThe teratogenic and carcinogenic effects of phthalate esters on living beings are proven in toxicology studies. These ubiquitous food and environmental pollutants pose a great danger to the human race due to their extraordinary use as a plasticizer in the consumer product industry. Contemporary detection techniques used for phthalates require a high level of skills, expensive equipment and longer analysis time than the presented technique. Presented research work introduces a real time non-invasive detection technique using a new type of silicon substrate based planar interdigital (ID) sensor fabricated on basis of thin film micro-electromechanical system (MEMS) semiconductor device fabrication technology. Electrochemical impedance spectroscopy (EIS) was used in conjunction with the fabricated sensor to detect phthalates in deionized water. Various concentrations of di(2-ethylhexyl) phthalate (DEHP) as low as 2 ppb to a higher level of 2 ppm in deionized water were detected distinctively using new planar ID sensor based EIS sensing system. Dip testing method was used to obtain the conductance and dielectric properties of the bulk samples. Parylene C polymer coating was used as a passivation layer on the surface of the fabricated sensor to reduce the influence of Faradaic currents. In addition, inherent dielectric properties of the coating enhanced the sensitivity of the capacitive type sensor. Electrochemical spectrum analysis algorithm was used to model experimentally observed impedance spectrum to deduce constant phase element (CPE) equivalent circuit to analyse the kinetic processes taking place inside the electrochemical cell. Curve fitting technique was used to extract the values of the circuit components and explain experimental results on theoretical grounds. The sensor performance was tested by adding DEHP to an energy drink at concentrations above and below the minimal risk level (MRL) limit set by the ATSDR (Agency for Toxic Substances & Disease Registry), USA. Results showed that the new sensor was able to detect different concentrations of phthalates in energy drinks. The experimental outcomes provided sufficient indication to favour the development of a low cost detection system for rapid quantification of phthalates in beverages for industrial use. © 2012 Elsevier Ltd. All rights reserved.
SponsorsThe authors would like to thank Massey University, New Zealand, for providing the best possible research facilities. The authors are obliged to COMSATS Institute of Information Technology and Higher Education Commission Pakistan, for providing support and funds to work on this project. Special thanks to all researches referenced throughout the paper whose valuable research has guided the way through to this research work, and to all whom. that had fruitful discussions and collaborations with the authors.
JournalJournal of Food Engineering