Turbidimetric determination of sulphate in plant digests and natural waters by flow injection analysis with alternating streams

✍ Scribed by F.J. Krug; E.A.G. Zagatto; B.F. Reis; O. Bahia F°; O. Jacintho; S.S. Jørgensen

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 646 KB
• Volume: 145
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(83)80060-9

✦ Synopsis

An improved flow injection system with alternating streams of reagents is described for the turbidimetric determination of sulphate. Samples are injected into an inert carrier stream which is mixed with barium chloride to form a barium sulphate suspension. The range of the method can be extended to low concentrations by continuously adding sulphate to the sample carrier stream. System performance is improved by automatic alternate pumping of the reagent stream and an alkaline EDTA solution at high flow rate. All operations are controlled by an electronicallyoperated proportional injectorcommutator. Even after routine analysis of 3000 samples of natural waters and plant digests, baseline drift was not observed. The proposed method is suitable for 120 samples per hour with a relative standard deviation less than 1% for sulphate concentrations in the range l-30 ppm (waters) or 5-200 ppm (plant digests). The results compare well with those obtained by standard manual procedures.