Dual-mode ion-selective electrodes and distance-based microfluidic device for detection of multiple urinary electrolytes.

Here, we developed a microfluidic paper device by combining ion-selective electrodes (ISE) and a distance-based paper device (dPAD) for simultaneous potentiometric and colorimetric detection of urine electrolytes including K, Na and Cl. The working and reference electrode zones were coated with polystyrene as a non-ionic polymer to improve hydrophobic properties on the paper surface for fabrication of K-ISE and Na-ISE. The layer of polymer coating was optimized to enhance the sensitivity of the ISEs.

A smartphone-assisted hybrid sensor for simultaneous potentiometric and distance-based detection of electrolytes.

At home electrolyte analysis is of growing interest due to the importance for early diagnosis for various diseases. This work presents the first device that integrates a potentiometric ion-selective electrode (ISE) with distance-based colorimetric detection for the simultaneous analysis of K and Cl ions at the point of care (POC). This hybrid sensing device was designed in a two-dimensional configuration using a plastic transparency sheet containing a stencil printed K-ISE and a paper substrate for distance-based colorimetric detection of Cl.

Distance-Based Paper Device for a Naked-Eye Albumin-to-Alkaline Phosphatase Ratio Assay.

The albumin-to-alkaline phosphatase ratio (AAPR) has been a cancer prognostic indicator. This paper presents the concept of a dual-color change distance-based paper device (dPAD) for albumin (Alb) and alkaline phosphatase (ALP) detection to evaluate this cancer prognostic index. Whereas Alb interacts with the bromocresol green (BCG) indicator to form a bluish-green complex, ALP hydrolyzes l-ascorbic acid-2-phosphate (AAP) to produce ascorbic acid (AA), which reacts with KIO to generate I and I.

Highly sensitive, selective and naked-eye detection of bromide and bromate using distance-based paper analytical device.

Bromine (Br) can usually be found as a bromide (Br‾) form contained in drinking water. Bromate (BrO‾) formation often occurred during the ozonation process in the presence of Br‾. BrO‾ is classified as a potential human carcinogen, so both the Br‾ and BrO‾ concentrations must be strictly controlled before and after an ozone-based treatment procedure, respectively.

A distance-based paper sensor for the determination of chloride ions using silver nanoparticles.

We report for the first time the development of a distance-based paper sensor for a simple, inexpensive, instrument-free, and portable determination of chloride ions. Our analysis reaction is based on the oxidative etching of silver nanoparticles (AgNPs) to form AgCl in the presence of Cl- and H2O2. H2O2 reacts with AgNPs in the channel of the paper device and Cl- in the sample forming a white precipitate (AgCl) where the white color band length is proportional to the Cl- concentration.