Analysis of inorganic anions in drainage water and soil solution by single-column ion chromatography (Abstract symposium)

Ponencia presentada en el 8th Symposium of Handling of Environmental and Biological Samples in Chromatography and and the 26th Scientific Meeting of the Spanish Group of Chromatograph. Celebrado del 26 al 29 de octubre, 1997, en Almería.Anions in drainage water and soil solution are comonly analysed by traditional methods (i.e ., I- by the fenic nitrate/mercuric thiocyanate spectrophotometric method, NO, by the sodic salicylate spectrophotometric method and SO: by the barium chloride turbidimetric method). Recently, ion chromatography has been found to be useful for analysing complex mixtures of anions in lesser time and with smaller sample volumes. Single column ionic chromatography (SCIC) is a method which can simultaneously detect F-, CI-, NO2- Br, NO3- PO4H= and SO4-, in water in less than 12 minutes. The aim of this study is the use of SCIC for anions determinations in Drainage water and soil solution. A low-capacity column (polymethacrylate resin with a quaternary ammonium functional group with 30±3 ueq·ml-1 of capacity) and a low conductivity mobile phase (a mixture of borate/gluconate, pH 8,5 and electric conductivity about 270 uS) were used in this study. Conductivity and Ultraviolet-Visible (214 nm) detectors were placed in series immediately after the separation column, the former for the detection of all anions in solution and the latter for a more selective and sensitive detection of nitrate and nitrite. Using a 100 ul sample loop the SCIC detection limits were 0.75 mg l-1 for CI 0.2 mg I-1 for NO,-N, 0.02 for NO,-N. 1.25 mg l-1 for PO4-P and 0.5 mg 1 for SO,-S. For these anions, results of SCIC method are highly reproducible in a wide range of concentrations (C.V 0.09-5.5% for CI-, NO2-N, NO3-N and SO4- S; and 4.6-10.1 % for PO4-P). Results for CI-, NO3-N and SO4-S by SCIC method were compared with those obtained by the traditional methods. Sludent-t test showed that the results of both methods agree closely (P