Electrochemical detection of Pb and Cd in paper-based microfluidic devices

Abstract

Tiras de papel de filtro combinadas com eletrodos de carbono impresso (SPCE) foram usadas na montagem de um dispositivo microfluídico para detecção de Pb(II) and Cd(II) em soluções aquosas. O dispositivo microfluídico portátil (com detecção eletroquímica direta) foi testado na quantificação direta de analitos (Pb(II) e Cd(II)) em amostras aquosas contaminadas sem pré-tratamentos. O sinal voltamétrico de redissolução anódica de onda quadrada (SWASV) foi bastante intensificado e apresentou excelente desempenho analítico na detecção de Pb(II) e Cd(II) (de 0 a 100 ppb) com baixo limite de detecção (2,0 e 2,3 ppb, respectivamente). Os dispositivos eletroquímicos propostos também apresentaram boa seletividade e estabilidade para análises de amostras reais de refrigerante e água subterrânea com contaminação física. O dispositivo é simples, de baixo custo, fácil fabricação e portátel. Este dispositivo analítico tem a possibilidade de ser útil em aplicações do tipo point-of-care no monitoramento ambiental, na saúde pública e na segurança alimentar.Filter paper strips combined with screen-printed carbon electrodes (SPCE) were used in the assembly of a microfluidic device for detecting Pb(II) and Cd(II) in aqueous samples. The portable microfluidic device (with direct electrochemical detection) was tested for direct quantification of multiple analytes (Pb (II) and Cd(II)) in contaminated aqueous samples without pretreatment. Square wave anodic stripping voltammetric (SWASV) signal was greatly enhanced and displayed excellent analytical performance for Pb(II) and Cd(II) detection (from 0 to 100 ppb) with low limit of detection of 2.0 and 2.3 ppb, respectively. The proposed electrochemical devices also exhibited good selectivity and stability for analyses of real samples of gas dissolved salty soda water and ground water with physical contamination. The device is simple, low-cost, easy-to-fabricate and portable. This analytical device has the possibility of being useful for point-of-care applications in environmental monitoring, public health and food safety.Keywords: microfluidic devices, screen-printed carbon electrodes, filter paper strip, portable device IntroductionAnalytical instrumentations tend to be miniaturization and intellectualization for in situ applications.1-4 Therefore, it can be convenient for real-time and on-line monitoring in the fields of environmental monitoring, biomedical science, agriculture, military analysis and industrial process monitoring, etc. Paper represents a great and useful supporting material for developing sensing devices owing to its various unique advantages, such as inexpensive, easy-printed, biodegradable and the porous structure facilitates lateral-flow assays suitable for chromatographic separations and as good filter.5-8 Screen-printing technology can be easily applied to the mass production of inexpensive, reproducible and sensitive disposable electrodes. 9,10Paper-based micro-electrochemical device integrated screen-printed carbon electrodes (SPCE) can meet the requirements fo...

Electrochemical paper‐based microfluidic devices

“…Currently, screen‐printing is used to create electrodes used in commercial electrochemical test strips, such as those used in combination with a handheld glucometer . External electrodes screen‐printed on polymer or ceramic materials fabricated in the lab or purchased commercially have also been used in combination with paper devices for electrochemical detection. Several options for commercially available modified SPCE on polymer are available, including PB‐modified, which has been used for ePAD detection .…”

“…Shi et al. detected Pb and Cd using SWASV at SPCEs with Bi added for application to water samples. A strip of paper continuously wicked sample across the electrodes causing an increase in metal accumulation relative to stagnant samples.…”

Microfluidic Paper-Based Analytical Devices (μPADs) and Micro Total Analysis Systems (μTAS): Development, Applications and Future Trends

“…Currently, most paper-based devices utilize colorimetric assays, although there have been reports of electrochemical sensing in paper-based devices for detection of glucose, lactate, and uric acid in biological samples [90] and heavy metal detection in water [138, 139]. In this work, a novel method of electrokinetic sensing in a paper-based microfluidic device was proposed.…”

Point-of-Care Diagnostics

“…Electrochemical sensors allowed the detection of glucose [94,95], lactate [94,95], uric acid [94], cholesterol [95], tumour markers [101], dopamine [106] and drugs [107]. Other studies described heavy metal sensors for environmental monitoring [94,96,99,100]. As compared to colorimetric reagents, the fabrication of electrochemical sensors required an additional deposition step of conductive inks on the paper matrix.…”