Sørensen used a slide-wire potentiometer to make his pH measurements. Here a known potential is applied to counterbalance the potential of the hydrogen cell (i.e. the hydrogen electrode plus the counter electrode) and to reduce its current output to zero, at which point the value of the applied counter-potential is equal to that of the cell potential. Since the point of balance is indicated by...

Suppose we are using a pH meter to test acidity/alkalinity of a solution used in a manufacturing process. The pH of pure water is 7.00. For samples in the pH range from about 5 to 9 the meter gives normally distributed readings with • μ equal to the true pH of the sample and • standard deviation σ = 0.20. The meter is tested each morning to make sure it is operating properly: n = 4 samples of p...

PURPOSE Urinary pH is an important factor linked to renal stone disease and a useful marker in the treatment of urolithiasis. Although the gold standard for measuring urinary pH utilizes a glass electrode and a pH meter, at present dipstick testing is largely used to estimate urinary pH. However, the accuracy and precision of this method may be insufficient for making clinical decisions in pati...

PURPOSE The aim of this study was to compare pH meter and neck ultrasonograph for evaluation of nasogastric tube (NGT) position. METHODS A total of 35 adult patients who required NGT insertion were included. The NGT was inserted by an anesthetist after endotracheal intubation, and the transducer was placed transversely on the neck, just superior to the suprasternal notch. The passage of the N...

The crystallization of proteins is dependent on the careful control of numerous parameters, one of these being pH. The pH of crystallization is generally reported as that of the buffer; however, the true pH has been found to be as many as four pH units away. Measurement of pH with a meter is time-consuming and requires the reformatting of the crystallization solution. To overcome this, a high-t...

A simple and rapid colorimetric pH meter has been developed based on the conformational switch of i-motif DNA and non-crosslinking AuNP aggregation, the average accuracy of the nano-meter was found to be +/-0.04 pH unit across the physiological operating range.

Objective: In children, excessive ingestion of fluoride from different sources including bottled drinking water and flavoured beverages or soft drinks can lead to the development of dental fluorosis. In addition, the pH level of beverages is important. Low pH can cause dental erosion. In this study we explore the fluoride content and pH level of certain popular beverages available in Malaysian ...