University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Inorganic compound

Classification: Inorganic compound -> carbon black

Citations 1

"Determination Of Nitrate In Carbon Black By Flow Injection Analysis With Potentiometric Detection"
Analusis 1997 Volume 25, Issue 2 Pages 32-35
IG. Canal, JLFC Lima, MCBSM Montenegro, R Prez-Olmos

Abstract: H2O (100 ml) was added to 10 g C black (details given) and the mixture incubated at 100°C for 5 min. The resulting suspension was filtered and the residue washed and diluted to 100 mL with water. A 150 µL portion was injected into channel 1 of a double channel manifold containing 10 µM-sodium nitrate. The resulting solution was mixed in a 70 cm reaction tube with carrier in channel 2 which comprised sodium sulfate or a solution of 0.02 M lead acetate, 0.01 M lead monoxide, 0.02 M potassium acetate and 0.01 M sulfamic acid. A flow rate of 6.8 ml/min was used. Nitrate levels were determined by an electrode which incorporated a PVC membrane and an ionic sensor based on tris(4,7-diphenyl-1,10-phenanthroline)nickel(II) complex dissolved in 2-nitrophenyl octyl ether. The lower limit of the linear range and the limit of detection were 70 and 30 µM, respectively. Levels of nitrate in C black are reported, with recoveries and RSD of 98.8-103.4% and 0.3-3.7% (n = 3), respectively. This paper reports the potentiometric detection of nitrate in carbon black samples by flow injection analysis (FIA). The detection system used consisted of a nitrate sensitive tubular electrode without inner reference solution, incorporating a PVC membrane with an ionic sensor based on tris(4,7-diphenyl-1,10-phenantroline) nickel(II) dissolved in 2-nitrophenyloctyl ether as the solvent mediator. According to the working characteristics of the tubular electrodes, a double channel flow injection system was constructed and optimized for direct sample analysis in a reduced time-frame. A solution of Pb(CH3COO)(2), PbO, CH3COOK and NH2SO3H was used as ionic strength and pH adjuster for both samples and standards. The tubular electrodes showed a linear response for a concentration of at least 5 10^-5 mol.L-1 with a slope of 58.3±0.9 mV/decade and a reproducibility of±0.1 mV within two successive calibrations. Analysis of 10 different samples from several factories showed satisfactory results with average recoveries of about 100.5%±1.5% and a variation coefficient of 1.5%. With the proposed system, a sampling rate of 120 samples/h was obtained. (11 References)
Nitrate Electrode Electrode Potentiometry Detection limit