Determination of chloride and sulphate ions by low-pressure ion chromatography

The deleterious effects on the quality of soil and ground waters of electrolytes discharged as a result of salts used by the tanning industry is of concern now more than ever. The electrolyte is usually in the form of chloride and sulphate and thus it is necessary to determination chloride ion and sulphate ion in tanning effluents. The determination of chloride ion and sulphate ion in leather pickling liquor is important to determine the salt's contribution to the total salt concentration of the sewage for each process. The aim of this work is to apply LPIC (without using a suppressor column) to the quantitative determination of chloride ion and sulphate ion in pickle liquor. Tests of precision, recovery and linear range were also conducted to evaluate the above method. The results show that the coefficients of variation are less than 4.77% or 3.76% with recoveries of 99.95% and 102.31% for chloride ion and sulphate ion respectively. Two calibration curves were obtained over the concentration range of 10 to 30 mg/L for chloride and 30 to 300 mg/L for sulphate. The detection limits of the method developed for chloride ion and sulphate ion are 0.144 and 2.853 mg/L respectively. LPIC performed without a suppressor column is shown to be suitable as a method for quantitative determination of chloride ion and sulphate ion in leather pickling liquor.