Flow injection system with multisite detection for spectrophotometric determination of calcium and magnesium in soil extracts and natural waters

• Type: Article in International Scientific Journal
• Date: 1996

Authors

Nogueira, ARA (Author) Other; Brienza, SMB (Author) Other; Zagatto, EAG (Author) Other; Lima, JLFC (Author) FFUP; Araujo, AJ (Author) FFUP

Journal

Title: Journal of Agricultural and Food Chemistry

Vol. 44

Pages: 165-169

ISSN: 0021-8561

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 19 Citations

Scientific classification

FOS: Agrarian Sciences > Other Agrarian Sciences

Other information

Authenticus ID: P-001-FBP

DOI: 10.1021/jf950168h

Abstract (EN): A flow system with a relocatable detector for spectrophotometric determination of calcium (Ca) and magnesium (Mg) in KCl soil extracts and natural waters is presented. O-Cresolphthalein complexon (CPC) was selected as the chromogenic reagent, ammonium-ammonia as the buffer system, and EGTA or 8-hydroxyquinoline as the masking agents for Ca or Mg, respectively. Linearity of the calibration equations was observed for Ca and Mg concentrations up to 80.0 and 15.0 mg/L, respectively. Slight variations in the coefficients of the calibration equations (usually <3%) were found after 4-h working periods. Recoveries between 97.5 and 104.1% were calculated after adding 10.0 mL of Ca at 15.00 mg/L or Mg at 5.00 mg/L Mg to 50.0-mL sample solutions. Precise results (relative standard deviation, <0.02) in agreement with flame atomic absorption spectrometry were obtained. With multisite detection, washing time was not a relevant factor in sampling rate, and an improved sample throughput of similar to 160/h (corresponding to 0.8 mg of CPC per sample) was obtained.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5