Less than 0.50 ppm 0.5 to 1.5 ppm More than 1.5 ppm Strontium zone boundary 22 Sampling site number Figure 1. Map of the United States showing concentration of strontium in surface water at selected sites

No abstract

The objective of the present project has been to develop a procedure for the flame photometric determination of Sr in natural water samples, utilizing the Beckman Modf' l DU spectrophotometer with flame photometer attachment, the oxygen-hydrogen flame, and a photomultiplier tube attachment. Of special concern was the determination of Sr at relatively low concentrations, i.e. 0 to 50 ppm.

Minor‐element content of water supplies has received relatively little study. A Denver investigation compares trace mineral contents of raw water against that of processed water.

minor changes in absorptivities were observed in 20 minutes. This indicates little immediate deterioration or complex formation on the addition of TONE (5). However, spectra of these solutions after 8 hours no longer resembled those of chlorophylls. DISCUSSIONIon exchange resin dehydrated with acetone provides a rapid method of conversion, separation, and determination of chlorophylls as pheophytins. The pheophytins obtained by this method are more stable than those obtained by oxalic or mineral acid conversion. This was shown by the reproducibility of spectrophotometric curves over a period of 12 months on samples kept at 0°C. The chlorophyll a and b ratio can be determined rapidly and with good precision by this