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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Classification: Ceramic -> kaolin

Citations 3

"Determination Of Aluminum In Kaolins By Flow Injection"
Analyst 1991 Volume 116, Issue 2 Pages 191-194
Anuchit Prownpuntu and Umaporn Titapiwatanakun

Abstract: Sample (0.2 g) was fused with 5 g of NaOH for 5 min, and the melt was extracted with water, the ppt. was dissolved in 6 M HCl, and the solution was diluted to 250 mL. A portion (10 ml) was made alkaline with aqueous 3 M NH3 until a ppt. appeared, 5 M acetic acid was added to dissolve the ppt., and the solution was diluted to 100 mL. An aliquot (75 µL) was injected into a stream (5 mL min-1) of 0.01% alizarin red S in ammonium acetate buffer (pH 4.5), the mixture was passed though a 50-cm reaction coil, and the absorbance was measured at 510 nm. The calibration graph was rectilinear for 25 ppm of Al, and the limits of detection and determination were 0.8 and 2 ppm, respectively. Recovery was quantitative. Results for several kaolins showed good agreement with those of an official method.
Aluminum Sample preparation Spectrophotometry Sample preparation Buffer Extraction Precipitation Standard method Method comparison

"Flow Injection Flame-atomic-spectrometric Determination Of Iron, Calcium, Magnesium, Sodium And Potassium In Ceramic Materials By Using A Variable-volume Injector"
Fresenius J. Anal. Chem. 1993 Volume 345, Issue 8-9 Pages 579-584
M. de la Guardia Contact Information, A. Morales-Rubio, V. Carbonell, A. Salvador, J. L. Burguera and M. Burguera

Abstract: A sample (0.1 g) of ceramic material (porcelain, feldspar, kaolin, varnish, clay or stoneware) was digested with LiBO2 (1 g) in a muffle furnace at 1000°C before dissolution in HNO3 and dilution with water. A variable-volume injector described previously (cf., Burguera et al., Anal. Chim. Acta, 1990, 234, 253) was used to simplify the online dilution and analysis of the samples (cf., Carbonell et al., J. Anal. Atomic Spectrom., 1991, 6, 233) by AAS and AES. The limits of detection were 100, 70, 50, 50 and 8 µg L-1 for Na, Ca, Fe, K and Mg, respectively. The calibrations were rectilinear with coefficient of variation between 0.5 and 2%. The results on 17 samples were comparable to those obtained by batch analysis.
Iron Calcium Magnesium Sodium Potassium Sample preparation Spectrophotometry Spectrophotometry Injector Valve Method comparison

"Spectrophotometric Determination Of Silicon In Kaolins By Flow Injection Analysis"
J. Sci. Soc. Thailand 1991 Volume 17, Issue 3-4 Pages 81-93
Prownpuntu, Anuchit; Titapiwatanakun, Umaporn (SFS)

Abstract: A flow injection analysis procedure is described by which dissolved silicon can be determined in complex aqueous media such as soil extracts. The spectrophotometric determination is based on yellow silicomolybdate. A soil sample solution is prepared by fusion with sodium hydroxide and subsequent dissolution of the cake in 6 M hydrochloric acid. The flow system permits high throughput of 120 samples h-1 without any carryover. The procedure has been applied to kaolins from various parts of Thailand and gave satisfactory agreement with the recommended method.
Silicon Spectrophotometry Method comparison