Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors

An Array-Type RGB Sensor for Precision Measurement of pH

“…Changes in RGB values could be identified for the color-change range of each indicator, in the acidic, neutral, and basic regimes. Methyl orange has a color-change of pH 2-8, bromthymol blue has a range near neutrality of pH 3-7, and phenolphthalein has a range of pH [8][9][10][11]. The values of G in particular tend to increase or decrease clearly over most of each range.…”

“…So far, several types of pH sensor have been developed, ranging from pH strips with low precision to precise pH meters using glass electrodes [7][8][9][10][11][12]. A pH meter is a device for measuring the hydrogen-ion concentration accurately, but the electrodes of a pH meter have the disadvantage of being broken easily by slight shock.…”

Label-free Detection of Prostate Specific Antigen at a Screen-printed Immunosensor Modified with a Nanostructured Gold Layer

“…This is attributed to the carbon particles within the ink formula consisting of predominantly basal planes. 24,25 The response to ferrocyanide after the electro-deposition of the gold stands in marked contrast with superior peak definition. The peak magnitude of the gold SPE is more than double that of the bare carbon with increased reversibility of the redox system where the peak separation has decreased to 71 mV.…”

“…24,25 The electro-oxidation (+2 V, 0.1 M NaOH) typically increases exfoliation of the carbon particles®generating more edge plane sites and increases the populations of various oxygen functional groups. 24,25 This process was also instituted here where it has been found that the unmodified screen-printed electrodes typically exhibit poor electrochemical behavior with large overpotentials necessary to obtain any significant analytical responses. 24 The electrodes were further modified through the electrodeposition of a gold layer.…”

Design of an optically stable pH sensor based on immobilization of Giemsa on triacetylcellulose membrane

“…Specially, these kinds of sensors suggest many advantages over the traditional systems, because of they offer the capacity of operating in hostile and dangerous environments [1][2][3][4]. The study of these sensors is attractive since they allow us to perform in vivo analysis and in situ monitoring.…”