ION-CHROMATOGRAPHIC DETERMINATION OF FLUORIDE IN WELDING FUMES WITH ELIMINATION OF HIGH CONTENTS OF IRON BY SOLID-PHASE EXTRACTION

• Type: Article in International Scientific Journal
• Date: 1994

Authors

VASCONCELOS, MTSD (Author) Other; Gomes, CAR (Author) FCUP; MACHADO, AASC (Author) Other

Journal

Title: Journal of Chromatography A

Vol. 685

Pages: 53-60

ISSN: 0021-9673

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 11 Citations

Other information

Authenticus ID: P-001-JAY

DOI: 10.1016/0021-9673(94)00664-4

Abstract (EN): An ion chromatography (IC) procedure was developed for the determination of fluoride in fumes from are-electric welding of steels with basic electrodes. The interference of metal ions was eliminated by passing the sample solution through an on-line pre-column of a strong cation-exchange resin. Both a strong acid (Hf form) resin and a strong chelating (Na+ form) resin were experimented for this purpose. Linear response was obtained from 0.02 to 1 mg of fluoride (in a 50-mu l loop), which corresponds to a concentration range from 0.15 to 7.5 mg/m(3) air (6 to 300% of the threshold limit value-time weighted average), for the experimental conditions used (2-h sampling periods, air flow-rate 17 l/cm(2).h, through a 1.2-mu m pore size cellulose nitrate filter, from which a l-cm diameter disk was attacked and analysed). The short-term (within 30 min) precision of the IC determination was <3% (7 determinations). The accuracy of the procedure was evaluated by analysing both synthetic solutions and real samples. When several mixed standard solutions of fluoride, iron(III) and aluminium(III), covering the ranges and ratios of concentration levels in real samples, were analysed, practically quantitative fluoride recovery (97-101%) was found. When 13 samples with 0.6-18 mg/l of fluoride were determined in parallel by IC (0.03-0.9 mu g injected) and a well established ion-selective electrode (ISE) procedure, no bias was found: a linear regression[IC] = 0.99 (+/- 0.12) [ISE] + 0.9 (+/- 1.4) (confidence limits at 95% confidence level in parentheses) was obtained.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8