Topic
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.
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TL;DR: The effects induced by nonionic surfactants on the EMF response function of hydrogen ion-selective polymeric membrane electrodes are modeled, and experimental results are shown to correlate well with theoretical predictions.
Abstract: The influence of poly(ethylene oxide)-based nonionic surfactants (i.e., Triton X-100 and Brij 35) in the sample phase on the response properties of hydrogen ion-selective polymeric membrane electrodes containing mobile (lipophilic amines) or covalently bound (aminated-poly(vinyl chloride)) hydrogen ion carriers is reported. In the presence of these nonionic surfactants, membrane electrode response toward interfering cation activity (e.g., Na+) in the sample phase is increased substantially and the pH measuring range shortened. The degree of cation interference for pH measurements is shown to correlate with the basicity of the hydrogen ion carrier doped within the membrane phase. The observed deterioration in selectivity arises from the partitioning of the surfactant into the membrane and concomitant extraction of metal cations by the surfactants in the organic phase. The effect of nonionic surfactants on pH electrodes prepared with aminated-PVC membranes is shown to be more complex, with additional large ...
41 citations
TL;DR: In this article, an adsorptive stripping voltammetric procedure for the determination of folic acid at an in situ plated lead film electrode was described, which was performed simultaneously from an acetate buffer solution of pH 5.6 at the potential −0.88
Abstract: An adsorptive stripping voltammetric procedure for the determination of folic acid at an in situ plated lead film electrode was described. Formation of lead film on a glassy carbon substrate and accumulation of folic acid was performed simultaneously from an acetate buffer solution of pH 5.6 at the potential −0.88 V. The measurements were carried out from aerated solutions. The calibration graph for an accumulation time of 300 s was linear from 2×10−9 to 5×10−8 mol L−1. The detection limit was 7×10−10 mol L−1, the relative standard deviation for 2×10−8 mol L−1 of folic acid was 3.9%. The proposed procedure was applied to folic acid determinations in pharmaceutical preparations.
41 citations
TL;DR: A natural Cameroonian smectite-type clay was exchanged with cationic surfactants, namely cetyltrimethylammonium and didodecyldimethyl ammonium modifying its physico-chemical properties to create organoclays that have higher adsorption capacity for mesotrione than the pristine SaNa clay, which have been used as modifiers of glassy carbon electrode for the electrochemical detection of this herbicide by square wave voltammetry.
41 citations
TL;DR: In this article, the dependence of electroosmotic flow on particle diameter and the influence of the mobile phase composition, i.e. organic modifier content, pH of buffer solution and concentration of buffer salt, on the magnitude of the EO flow velocity has been investigated.
Abstract: Reversed-phase stationary phases based on porous silica beads in the range 0.2–3 μm have been prepared to study the dependency of electroosmotic flow (EOF) on particle diameter. Additionally, the influence of the mobile phase composition, i.e. organic modifier content, pH of buffer solution and concentration of buffer salt, on the magnitude of the electroosmotic flow velocity has been investigated. To perform separations in an aqueous acidic mobile-phase, mixed mode stationary phases containing both alkyl chains and strong cationexchange groups have been applied.
41 citations
TL;DR: Preliminary results, using an excimer laser operated at 248 nm, show that the fluorescence intensity of isonicotinic acid is substantially enhanced with the addition of 0.3% hydrogen peroxide to the phosphate buffer system.
41 citations