a simple method has been developed for the preconcentration of lead (ii) based on the adsorption of its 1-(2-pyridyl azo)2-naphtol (pan) complex on aoctadecyl bonded silica cartridges. the influence of acidity, eluting agents, stability of the column, sample volume and interfering ions has been investigated in detail. the adsorbed complex could be eluted using environmentally benign hno34m and ...

A non-sooting lifted methane/air coflowing non-premixed flame has been studied experimentally and computationally. The flame structure was computed using a model that solves the fully elliptic governing equations, utilizes detailed transport coefficients and a chemical kinetic mechanism with C1 to C6 hydrocarbons, and includes an optically thin radiation submodel. Gas temperature, major species...

The oxidation of methyl formate (CH3OCHO), the simplest methyl ester, is studied in a series of burnerstabilized laminar flames at pressures of 22–30 Torr and equivalence ratios (U) from 1.0 to 1.8 for flame conditions of 25–35% fuel. Flame structures are determined by quantitative measurements of species mole fractions with flame-sampling molecular-beam synchrotron photoionization mass spectro...

We present an improved Na+-selective liquid membrane electrode for measurement of Na+ concentrations in both undiluted serum and urine. The values for urinary Na+ obtained with the ion-selective electrode agree well with those obtained with the flame photometer. The correlation gives a standard residual deviation of +/- 2.7 mmol/L over the Na+ range of 25-280 mmol/L. In serum, this direct poten...

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