Buffer solution

About: Buffer solution is a research topic. Over the lifetime, 6948 publications have been published within this topic receiving 112440 citations. The topic is also known as: pH buffer & buffer.

Electrophysiological identification of antennal pH receptors in the ground beetle Pterostichus oblongopunctatus.

Abstract: . Electrophysiological responses of antennal taste bristles to 100 mm acetate and phosphate buffers were tested at pH 3–11 in the ground beetle Pterostichus oblongopunctatus (F.) (Coleoptera, Carabidae). Additionally, responses of these sensilla to 10 and 100 mm phosphate buffers were compared with each other. Generally, in response to these stimulating solutions, two sensory cells, classified as a salt cell (cation cell) and a pH cell, respectively, showed action potentials distinguished by differences in their amplitudes and polarity of spikes. The firing rate of the cation cell increased with increasing buffer concentration, and was influenced by buffer pH in a complicated way. The best stimulus for the second cell (pH cell) was pH of the stimulating buffer solution. As the pH of the stimulus solution increased, higher rates of firing were produced by the pH cell. For example, the number of action potentials elicited by 100 mm phosphate buffer at pH 11.1 was approximately 16-fold higher compared with that at pH 8.1, and firing rates during the first second of the response were 27.9 and 1.7 imp/s, respectively. The pH cell did not fire or fired at very low frequency (first second response below 5 imp/s) at pH 3–6. This level of acidity probably represents the pH preferences of this ground beetle in its forest habitat and hibernating sites. By contrast to the cation cell, the pH cell responded to increases in buffer concentration by decreasing its firing rate.

A Carbazole‐Containing Difunctional RuII Complex That Functions as a pH‐Induced Emission Switch and an Efficient Sensitizer for Solar Cells

Abstract: A heteroleptic ruthenium(II) complex of [Ru(Hecip)(Hdcbpy) (NCS)2]–·[N(C4H9)4]+ (where Hecip = 2-(9-ethyl-9H-carbazol-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline and Hdcbpy = monodeprotonated 2,2′-bipyridyl-4,4′-dicarboxylic acid) has been synthesized and characterized by elementary analysis, cyclic voltammetry, MALDI-TOF mass spectrometry, and 1H NMR, IR, UV/Vis absorption, and emission spectroscopy. The ground- and excited-state acid–base properties of the complex have been studied by means of UV/Vis absorption spectrophotometric and spectrofluorimetric titrations in a Britton–Robinson/DMF (v/v, 4:1) buffer solution. The complex was found to act as pH-induced off-on-off/on-off-on-off-type emission switch, when excited at 530/470 nm, with a protonation/deprotonation reaction taking place near the physiological pH range. The performance of the complex-sensitized TiO2 nanocrystalline solar cell with 0.05 M I2 and 0.5 M LiI in 50 % acetonitrile and 50 % propylene carbonate (PC) as the electrolyte solution and a platinum film as the counter electrode has also been studied, and was compared to that of the cis-[Ru(H2dcbpy)2(NCS)2] (N3)-sensitized solar cell under the same experimental conditions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)