Capacitively coupled contactless conductivity detection on microfluidic systems—ten years of development† Wendell Karlos Tomazelli Coltro, ab Renato Sousa Lima, bc Thiago Pinotti Segato, bc Emanuel Carrilho, bc Dosil Pereira de Jesus, bd Claudimir Lucio do Lago be and Jos e Alberto Fracassi da Silva * bd Received 20th June 2011, Accepted 22nd August 2011 DOI: 10.1039/c1ay05364g The use of capacitively coupled contactless conductivity detection (C 4 D) on miniaturized systems has increased considerably over the last few years. Since the first report, 10 years ago, several advances on the detection cell geometry, strategies for increasing the sensitivity and a wide range of applications have been reported. This review intends to cover the main features related to the instrumental setup of this detection method for analytical and bioanalytical assays on microfluidic chips. Introduction The use of microfluidic platforms for chemical and biochemical applications has achieved remarkable progress in the last two decades. 1–4 The miniaturization of analytical components (valves, pumps, mixers, pH regulators, reactors, etc.), the development of ultrasensitive methods, and the integration of different detectors with separation techniques are attractive features in this field. 1,2 Although a rapid advance has been observed in this area, greater efforts should be spent to fabricate and use real micro total analysis systems (mTAS). 5 These devices, which were conceptually designed in 1990 by Manz et al., 6 involve the on-chip integration of multiple analytical steps including sampling, sample pretreat- ment, separation, chemical reactions, detection, and even elec- tronics for data acquisition. This characteristic is highly relevant in many cases, such as in clinical diagnostics and health care. 7 Over the past years, different detection systems, including fluorescence, 8 mass spectrometry, 9 and electrochemical detec- tors, 10–12 have been coupled with microfluidic systems. Due to its inherent compatibility with miniaturization techniques, electro- chemical detection is becoming increasingly popular for on-chip a Instituto de Qu ımica, Universidade Federal de Goi  as, Campus Samambaia, 74001-970 Goi ^ ania, GO, Brazil. E-mail: wendell@quimica. ufg.br; Fax: +55 62 3521-1127 b Instituto Nacional de Ci^ encia e Tecnologia de Bioanal  ıtica, Campinas, SP, Brazil c Instituto de Qu ımica de Sa˜o Carlos, Universidade de Sa˜o Paulo, 13566-970 Sa˜o Carlos, SP, Brazil. E-mail: emanuel@iqsc.usp.br d Instituto de Qu ımica, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brazil. E-mail: fracassi@iqm.unicamp.br e Instituto de Qu ımica, Universidade de Sa˜o Paulo, 05508-900 Sa˜o Paulo, SP, Brazil. E-mail: claudemi@iq.usp.br † This article is part of a web theme in Analyst and Analytical Methods on Future Electroanalytical Developments, highlighting important developments and novel applications. Also in this theme is work presented at the Eirelec 2011 meeting, dedicated to Professor Malcolm Smyth on the occasion of his 60th birthday. Wendell Karlos Tomazelli Coltro Wendell K. T. Coltro received his MS (2004) and PhD (2008) in Chemistry (Analytical Chemistry Concentration) from University of Sao Paulo. Since 2009, he has been an Assistant Professor at Institute of Chem- istry from Federal University of Goias, Brazil. His research interests involve the development of alternative microfabrication technologies (toner-based tech- nologies), coupling of electro- chemical detectors and bioanalytical assays on micro- fluidic devices. Thiago Pinotti Segato Thiago P. Segato, PhD, is a postdoctoral student at the Institute of Chemistry at Sao Carlos, Brazil, and an associate researcher at the INCTBio. His current research is focused on fabrication of microfluidic chips and their coupling with detection techniques. This journal is ª The Royal Society of Chemistry 2012 Anal. Methods, 2012, 4, 25–33 | 25 Dynamic Article Links C < Analytical Methods Cite this: Anal. Methods, 2012, 4, 25 www.rsc.org/methods CRITICAL REVIEW Downloaded on 11 January 2012 Published on 07 October 2011 on http://pubs.rsc.org | doi:10.1039/C1AY05364G View Online / Journal Homepage / Table of Contents for this issue