Stop sell orders have been placed on commercial coolants due to regulatory findings that concentrations of denatonium benzoate (DNB) are too low. Most of these have been checked elsewhere by the ASTM D7304 method and are not confirming low DNB concentrations. A quick D15 Committee check determined that the D7304 method must be improved and discovered that precision & bias have not been established. Several shortcomings in the published method have been identified that can lead to disparate results for DNB, a regulated ingredient. This Work Item has the objective to improve the method and establish a P&B statement so that satisfactory agreement between laboratories can be established.
analytical method; antifreeze; Bitterant; chromatography; denatonium ion; denatonium benzoate; engine coolant; HPLC;
Citing ASTM Standards
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