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
Email: schalk@unf.edu
Website: @unf

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Spectrophotometry

Citations 5

"Determination Of Sulfur Anions By Flow Injection With A Molecular Emission Cavity Detector"
Anal. Chim. Acta 1984 Volume 157, Issue 1 Pages 177-181

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J. L. Burguera and M. Burguera

Abstract: A molecular-emission cavity detector is attached to a flow injection system for the determination of S2-, SO32- and SO42- in the ranges 2 to 130, 3 to 150 and 5 to 250 ng of S, respectively, in 3 µL samples. Experimental details are given. The effects of flow rate of solution into the cavity are discussed. For determinations of SO42-, the coefficient of variation is 2.0% for 3 ng of S. The analytical signal is available within 30 s after sample injection, permitting ~100 measurements in 1 h. If the carrier stream is changed from water to H2O2 solution, only one peak is obtained corresponding to total S. Recovery of SO32- and S2- ranges from 90 to 95%.
Sulfide Sulfite Sulfate

"Determination Of Some Phosphorus-containing Compounds By Flow Injection With A Molecular Emission Cavity Detector"
Anal. Chim. Acta 1985 Volume 170, Issue 2 Pages 331-336

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J. L. Burguera, M. Burguera and Daniel Flores

Abstract: Optimum conditions (e.g., flow rate, sample volume, dimensions of the tubing and flame composition) have been established for the determination of P-containing inorganic and organic compounds by the cited technique. The ranges of rectilinear response, detection limits and coefficient of variation (typical values being 10 to 200 ng, 2.5 and 3%, respectively) are tabulated for H3PO4, H3PO3, H3PO2, trimethyl phosphite, triethyl phosphite and tributylphosphine; sensitivity improved with decreasing O content of the compounds. The sample throughput was 20 h-1. As peaks were well separated, components of ternary mixtures could be determined.
Phosphorus Phosphoric acid Phosphorus acid Hypophosphorus acid Trimethylphosphite Triethylphosphite Tributylphosphine Optimization

"Determination Of Some Organophosphorus Insecticides By Flow Injection With A Molecular Emission Cavity Detector"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 497-502

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J. L. Burguera and M. Burguera

Abstract: The insecticides are extracted from waters into hexane - CH2Cl2 (17:3) at pH <7 followed by measurement of the HPO emission at 528 nm vs. time in the system previously described (Ibid., 1985, 170, 331). Dicrotophos and dimethoate are measured in the range of 5 to 100 ng of P and malathion and parathion from 10 to 120 ng with detection limits between 0.8 and 2.5 ng. Recoveries are between 73.4 and 98.1% for 50 ng of P with coefficient of variation between 2.5 and 3.4% for 20 ng (n = 8).
Insecticides Dicrotophos Dimethoate Malathion Parathion Environmental Extraction

"Continuous-flow Molecular Emission Cavity Analysis For Organic Sulfur Compounds By Alkaline Hydrolysis"
Anal. Chim. Acta 1988 Volume 204, Issue 1-2 Pages 285-293

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N. Grekas and A. C. Calokerinos

Abstract: The alkaline hydrolysis (4 M NaOH) of thioacetamide, thiosemicarbazide, thiodiacetic acid and dithio-oxamide at 45°C in a continuous-flow automatic analyzer. is described. The S2- produced is removed from the solution after acidification with 4 M H3PO4 and the H2S evolved is purged with N and determined by MECA. The sampling rate is 30 h-1, and the coefficient of variation is 1 to 2.5%.
Heated reaction

"Automated Determination Of Nanogram Amounts Of Phosphorus By Molecular Emission Cavity Analysis"
Anal. Proc. 1982 Volume 19, Issue 6 Pages 320-321

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I. H. El-Hag

Abstract: Molecular emission cavity analysis (MECA)1 is a flame photometric technique that relies on a cool flame source to generate band emissions, such as those from S,, BO, and HPO. The conventional manual method involves depositing the microlitre-volume sample into a cavity cut into the end of a rod, which is introduced manually to the flame, so that the emission generated within the cavity is viewed by the detector. The reproducibility of this method is unsatisfactory for fast emitting species because variables such as the exact time of injection, cavity residence time in the flame and cooling time after analysis need precise control.
Phosphorus