AUTOMATED CHEMICAL-ANALYSIS FOR MEASURING MICROGRAM LEVELS OF ORGANIC-CARBON IN POTABLE WATERS

An automated method for the direct determination of microgram levels of organic carbon in potable waters is described. The technique is that of continuous flow analysis and utilizes an automatic sampler, a multiple channel proportioning pump, and an appropriate analytical system (manifold). Samples are acidified, oxygen segmented and passed through a heated inorganic carbon stripper. The stripped liquid is resampled, mixed with silver peroxydisulphate solution and digested at 70°C. The liberated CO2 is measured by means of infrared photometry. Complete inorganic carbon removal was not possible. From a 30 mg dm-3 inorganic carbon solution 0.1% residual remained after stripping. Using a sample volume of 6.3 cm3 min-1, full-scale recorder deflection could be obtained for a 1 mg dm-3 organic carbon standard solution with a relative standard deviation of 0.9%. The lower detection limit of practical significance is 50 μg dm-3 organic carbon. The analysis rate is 20 samples per hour. Certain synthetic organic materials resisted complete oxidation and included the amino acids glycine, 1-alanine, leucine, iso-leucine and valine. © 1979.