A sensitive method for the determination of the herbicide pindone by adsorptive stripping voltammetry using a hanging mercury drop electrode at pH 4.0 was described. The cyclic voltammogram of pindone demonstrates that compound was adsorbed at the surface of mercury electrode, and the overall reduction process was under controlled diffusion. The adsorptive peak was observed at −0.3 V, and peak ...

Taking into account the use of Nickel brasses in industry a great number of methods for the determination of Ni have been reported. More, theoretical predictions of free Cd increasing with decreasing salinity have been confirmed using cadmium selective electrodes. The method under proposal, for the determination of nickel ions in brass alloys consists of the following steps: Cu masking with sod...

The spectrophotometric determination method of scandium with eriochrome cyanine R (ECR) and the composition ratio of the complex were investigated in the presence of surfactants. A volume of 5 mL of 1.0×10−3 M ECR and 10 mL of 2.0×10−4 M CTMAB are necessary for the determination of 1.0×10−7 ~ 3.0×10−6 M Sc(III) at pH 6.5. The apparent molar absorption coefficient of the Sc(III)-ECR-CTMAB, terna...

We used three methods to examine the relationship among intracellular pH, transmembrane potential, and extracellular pH. Single-barreled electrodes permitted the determination of resting potential and intracellular pH with a minimum of cellular injury. Double-barreled electrodes, which incorporated a reference as well as a pH-sensitive electrode in a single tip, facilitated the direct measureme...

The demand for easy-to serve fish based products, like frankfurters, is increasing, thanks to their convenience and quick preparation. In this study, cooked and cold-smoked salmon based frankfurters were evaluated for chemical-physical and microbiological characteristics during 90-days storage at 4°C. Every 15 days of storage, samples were submitted to complete microbiological analyses and to t...

A method is described for determination of oxalic acid in urine using atomic absorption spectrophotometry. The concentration of urinary oxalic acid is calculated by using the difference between two determinations of calcium: first, the excess of calcium in the supernatant after precipitation as calcium oxalate at pH 5, and second, the total calcium determined at pH less than 1 (endogenous and a...

A high-performance liquid chromatographic multiresidue method was developed for the determination of 8 penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, amoxicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in muscle tissue. This method involves extraction of the penicillins with phosphate buffer pH 9 followed by cleanup and concentration ...

A colorimetric method for the determination of serum guanase has been developed whereby ammonia, formed by the deamination of guanine, is measured by the phenatehypochlorite reaction. Variations in substrate concentration, time of incubation, pH, temperature, and concentration of enzyme have been investigated with respect to enzyme activity. The determination of serum guanase appears to be usef...

A spectrofluorimetric method to determine tacrine is proposed and applied to the determination of tacrine in human serum and pharmaceuticals. The fluorimetric method allows the determination of 1-70 ng ml-1 of tacrine in aqueous solutions containing acetic acid-sodium acetate buffer (pH 5.6) with lambda exc = 242 nm and lambda em = 362 nm.

Here we report the rational development of a carbon dot (CDs)-based fluorescent pH nanosensor by employing an active surface preservation strategy. More specifically, citric acid, urea and fluorescein were subjected to one-pot hydrothermal treatment, which preserved fluorescein-like structures on CDs. The obtained CDs showed pH-sensitive green emission, can be used determine variations from 3.7...