| Popis: |
The flame photometric determination of sodium and potassium in plant ash extracts has been studied with particular reference to interferences; the instrument used was a Beckman spectrophotometer model DU, with a flame attachment of the total consumption burner type. The ions Na, K, Ca, Mg, NO 3 − , PO 4 −3 and SO 4 −2 were tested; sodium and potassium had a strong mutual enhancement effect which could cause errors up to 25%, but which could be compensated by adding the interfering elements to the standards. Interference effects prevented the direct determination of calcium in plant ash extracts, hence calcium oxalate was precipitated and dissolved and the solution was read in the flame photometer. This method was preferable to chemical methods particularly when sodium and potassium were to be determined in the same sample. |
