Here we report a smartphone-based potentiometric biosensor for point-of-care testing of salivary α-amylase (sAA), which is one of the most sensitive indices of autonomic nervous system activity, and therefore a promising non-invasive biomarker for mental health. The biosensing system includes a smartphone having a sAA-detection App, a potentiometric reader and a sensing chip with preloaded reag...

Poisoning due to ingestion of foods with elevated levels of biogenic amines (histamine, putrescine, cadaverine, and tyramine) is well documented. Histamine fish poisoning largely is due to growth of naturally occurring bacteria associated with scombroid fish species. A rapid and reliable method is needed to screen for the presence of histamine-forming bacteria in fish. This study included a com...

2-amino-n-benzthioazolyl benzamide (abtb) was synthesized, characterized and used for thefabrication of a potentiometric sensor for cu2+ metal ions. the electrode exhibits linear response to cu(ii) over a wide concentration range (4.79×10 -8 – 1.85×10 -1 m) with nernstian slope of 30 ± 1.5 mvper decade. the electrode can be used in the ph range from 2 to 9. it has a fast response time of about1...

A direct potentiometric titration method was applied for determination of Ranitidine Hydrochloride. The method is based on the treatment of the primary data with nonlinear regression procedure using commercial software. A general formula valid for every type of acid base titration, derived before is used as a direct input. The acid-base constants of N, N dimethyl-5 [2-(1-methylamine-2-nitroviny...

A novel potentiometric solid-state reference electrode containing single-walled carbon nanotubes as the transducer layer between a polyacrylate membrane and the conductor is reported here. Single-walled carbon nanotubes act as an efficient transducer of the constant potentiometric signal originating from the reference membrane containing the Ag/AgCl/Cl(-) ions system, and they are needed to obt...

Sodium was determined by flame photometry and by direct potentiometry in 56 serum or plasma samples from 24 patients with multiple myeloma or macroglobulinemia. We observed differences between the two techniques as large as 17 mmol/L (12%). The flame-photometric values decreased relative to the direct-potentiometric values as protein increased or water content decreased. Moreover, the two sodiu...

EPR-based potentiometric titrations are a well-established method for determining the reduction potentials of cofactors in large and complex proteins with at least one EPR-active state. However, such titrations require large amounts of protein. Here, we report a new method that requires an order of magnitude less protein than previously described methods, and that provides EPR samples suitable ...

A convenient reference cell and method of potentiometric determination of chloride ions with silver nitrate is described. The method is accurate to about +/- 0.02 ml. 10(-4)M silver nitrate.

Two analytical methods, which prove the utility of a potentiometric flow injection technique for determining various redox species, based on the use of some redox potential buffers, are reviewed. The first is a potentiometric flow injection method in which a redox couple such as Fe(III)-Fe(II), Fe(CN)(6) (3-)-Fe(CN)(CN)(6) (4-), and bromide-bromine and a redox electrode or a combined platinum-b...