Multiplexed Ultra-Sensitive Detection of Cr(III) and Cr(VI) Ion by FET Sensor Array in a Liquid Medium

Abstract

Chromium, one of the top five toxic heavy metals ranked according to significance in public health by WHO, exists as Cr(III) which is naturally occurring or Cr(VI) which is anthropogenic in origin. The EPA specifies the maximum contaminant level in drinking water to be 10−6 M or 0.1 mg/L or 100 ppb for the total dissolved Cr. To ensure the water consumed by the population has these pollutants below the safe threshold, this report demonstrates a field effect transistor (FET) based sensor design incorporating a highly target specific ion-selective membrane combined with extended gate technology which manifests sensitivity exceeding the Nernst limit aided by the high field effect in the short gap region of extended gate technology. Characterization and repeated testing of the portable device revealed a commendable calibration sensitivity of 99 mV/log [Cr3+] and 71 mV/log [Cr6+] for Cr(III) and Cr(VI) respectively, well surpassing the Nernst limits of sensitivity and offering a detection limit lower than ion-selective electrodes (10−6 M), and comparable to the expensive benchtop laboratory instrument, ICP-MS. This report presents a robust, easy to fabricate, economic and efficient handheld biosensor to detect the chromium in a liquid sample whether it exists as Cr(III) or Cr(VI).

Molecularly imprinted polymersviareversible addition–fragmentation chain-transfer synthesis in sensing and environmental applications

“…Its molecular recognition capability, sensitivity, and dimensions create an attractive hybrid solution that combines nature's performance and selectivity as a signal transducer with electronics 99 that are used and commercialized as a sensor. [30][31][32][33][34][35][36][37][38] However, the main challenge with this architecture is that it stills rely upon physiological conditions such as pH and temperature. A solution to overcome this challenge has been to use the molecularly imprinted polymer (MIP) technique, which mimics the key-lock principle with synthetic molecular structures.…”

Peroxidase Mimic Activity of Au–Ag/l-Cys-rGO Nanozyme toward Detection of Cr(VI) Ion in Water: Role of 3,3′,5,5′-Tetramethylbenzidine Adsorption

“…Cr­(VI) is 100–1000 times more toxic in comparison to Cr­(III). Cr­(VI) has a high oxidation potential and is extensively distributed in wastewater systems all over the world, which causes a severe hazardous impact to the environment and human health . According to the World Health Organization (WHO), the maximum acceptable amount of Cr­(VI) in drinking water is 0.05 ppm .…”

“…Cr(VI) has a high oxidation potential and is extensively distributed in wastewater systems all over the world, which causes a severe hazardous impact to the environment and human health. 34 According to the World Health Organization (WHO), the maximum acceptable amount of Cr(VI) in drinking water is 0.05 ppm. 35 On the other hand, the other oxidation state Cr(III), is an essential component of the glucose tolerance factor, and responsible for controlling the body lipid metabolism rate as well as cholesterol and triglyceride levels in the blood.…”

Wearable Multiparameter Platform Based on AlGaN/GaN High‐electron‐mobility Transistors for Real‐time Monitoring of pH and Potassium Ions in Sweat

“…Recently, electrochemical sensors have become commonly used in wearable devices. Ion sensitive field effect transistors (ISFETs), which are widely reported to have advantages such as fast response, low detection limits, good integration and low power consumption and are also considered good candidates for wearable devices. Nakata and colleagues developed the first ISFET to continuously monitor sweat pH and skin surface temperature, but it requires a large amount of exercise to collect sweat .…”