Stopped-flow injection spectrophotometric method for determination of chlorate in soil

A stopped-flow injection (FI) spectrophotometric procedure based on iodometric reaction for the determination of chlorate has been developed. Standard/sample was injected into a stream of potassium iodide solution and then merged with a stream of hydrochloric acid solution to produce triiodide. By stopping the flow while the sample zone is being in a mixing coil, a slow reaction of chlorate with iodide in acidic medium was promoted to proceed with minimal dispersion of the triiodide product zone. When the flow started again, a concentrated product zone was pushed into a flow cell and a signal profile due to light absorption of the product was recorded. Employing a lab-built semi-automatic stopped-FI analyser, the analysis can be performed with higher degree of automation and low chemical consumption. Linear calibration graph in the range of 5-50 mg ClO3 - L -1 was obtained, with detection limit of 1.4 mg ClO3 - L -1 . Relative standard deviation of 2.2% (30 mg ClO3 - L -1 , n=10) and sample throughput of about 20 h -1 were achieved. The system was applied to soil samples and validated by batch spectrophotometric and standard titrimetric methods.

[1]  K. Grudpan,et al.  Stopped-flow injection method for determination of phosphate in soils and fertilisers , 2008 .

[2]  M. Cunha,et al.  Ultrastructural, physiological and biochemical analyses of chlorate toxicity on rice seedlings , 2004 .

[3]  J Ruzicka,et al.  Stopped-flow injection simultaneous determination of phosphate and silicate using molybdenum blue. , 2002, Talanta.

[4]  H. S. Srivastava.  Multiple functions and forms of higher plant nitrate reductase , 1992 .

[5]  D. Nikolelis,et al.  Kinetic study of the iodate—iodide and chlorate—iodide reactions in acidic solutions, and a method for the microdetermination of bromide , 1977 .

[6]  John C. Guyon,et al.  Spectrophotometric determination of chlorate ion , 1968 .

[7]  B. Logan,et al.  Chlorate and nitrate reduction pathways are separately induced in the perchlorate-respiring bacterium Dechlorosoma sp. KJ and the chlorate-respiring bacterium Pseudomonas sp. PDA. , 2004, Water research.

[8]  U. Gunten,et al.  Determination of chlorate at low μg/l levels by ion-chromatography with postcolumn reaction , 1999 .

[9]  M. Biesaga,et al.  Separation of chlorine-containing anions by ion chromatography and capillary electrophoresis 1 Presented at the International Ion Chromatography Symposium, Reading, 16–19 September 1996. 1 , 1997 .

[10]  Jaroon Jakmunee,et al.  A novel stopped flow injection-amperometric procedure for the determination of chlorate. , 2005, Talanta.

[11]  P. Dasgupta,et al.  Simultaneous flow-injection measurement of hydroxide, chloride, hypochlorite and chlorate in Chlor-alkali cell effluents. , 2000, Talanta.

[12]  A. Bloom,et al.  Chlorate as a Transport Analog for Nitrate Absorption by Roots of Tomato , 1996, Plant physiology.

[13]  G. Gordon,et al.  Determination of low concentrations of chlorite and chlorate ions by using a flow-injection system , 1989 .

[14]  K. Grudpan.  Some recent developments on cost-effective flow-based analysis. , 2004, Talanta.

[15]  A. L. Underwood,et al.  Infrared determination of chlorate in the presence of other oxyhalogen anions , 1963 .

[16]  G. Gordon,et al.  Utilisation of kinetic-based flow injection methods for the determination of chlorine and oxychlorine species , 1989 .

[17]  Barry Chiswell,et al.  Spectrophotometric method for the determination of chlorite and chlorate , 1993 .