Sample Weight: 0.5 g
Chloride is determined by Ion-Selective Electrode (ISE) following a potassium hydroxide fusion. The sample is fused with a mixture of potassium hydroxide and potassium nitrate to release chloride ions from the sample matrix followed by dissolution of the fusion cake in dilute nitric acid. Prior to measuring the chloride activity of the sample solution using an ion-selective electrode, the sample is spiked with known chloride amount and an ammonium citrate solution is added to buffer the pH, maintain a constant ionic strength, and dissociate any metal ion-chloride complexes. The chloride concentration in the sample is then determined by interpolation from standard calibration curves.
The reporting limit range for Chloride is 0.01% to 30%.
Data will be deemed acceptable if recovery of Chloride is ±20% at five times the Lower Limit of Determination (LOD) and the calculated Relative Standard Deviation (RSD) of duplicate samples is no greater than 20%.
Central Mineral and Environmental Resources Science Center