Glass electrode determination of sodium in closed basin waters

Because of its direct relation to total dissolved solids content, sodium concentration is the most useful single hydrochemical parameter of closed basin waters in the western United States. Therefore, it is advantageous to have a rapid method for sodium determination which could be readily adapted to field use. Accordingly, thirty waters of highly variable concentration and anionic composition from the western Great Basin have been analyzed with a sodium-sensitive glass electrode. Na⁺ values ranged from 10 to 130,000 ppm in waters containing from 102 to 401,000 ppm total dissolved solids. The electrode values were compared with conventional sodium determinations; results differed by as much as 11 per cent, although over two-thirds were within 5 per cent. No significant relation was found between the glass electrode and conventional method differences and the total dissolved solids or sodium concentration. The comparative accuracy of electrode and conventional procedures was checked, employing solutions of known sodium concentration. It was concluded that for the analysis of sodium in natural waters the glass electrode method offers results comparable in accuracy to those obtained by conventional methods, but with increased simplicity, and therefore the possibility of rapid, accurate field measurements.