Rationale

The industry has observed improvements in the performance of newer D3606 separation gas chromatographic columns used in the apparatus for D3606 Procedure B. The attached proposed procedure for optimizing the apparatus enhances the existing method, making it more reliable and foolproof. As a result, it is being included as an alternative procedure. This new procedure provides an increased safety margin, ensuring that C9+ hydrocarbons do not interfere with the analysis of benzene and toluene. It is being incorporated as an Annex.