ASTM D6729 Method for Individual Components in Spark Ignition Engine Fuels
ASTM D6729 Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary High Resolution Gas Chromatography
9. Procedure
9.1 Set the operating conditions of the gas chromatograph as shown in Table 1. These conditions will elute all components up to and including pentadecane (nC15).
9.2 All of the parameters in Table 1 can be marginally changed to optimize for sample types and optimize for characteristics of each gas chromatographic system. The final boiling point of samples should not exceed nC15 and the column resolution (R) performance requirements listed in Table 2 should not be compromised.
9.3 Obtain a representative sample following the guidelines of Practice D4057 and any other applicable guidelines. Take precautions to minimize the loss of light ends from volatile samples. The sample container may be cooled prior to transfer of sample into it. Cool the sample to less than 4°C, maintain at that approximate temperature until the autosampler is loaded and analysis begins.
9.4 Preparation/Storage:
9.4.1 Samples Stored in Vials - Cool the original sample to less than 4°C prior to taking a sample aliquot or prior to filling the sample vials. The sample aliquot container, or the vial, or both, can also be cooled prior to the transfer of the original sample. Syringes may also be cooled along with the sample for manual injections.
9.4.2 Samples Stored in Pressurized Containers - It is recommended that they be kept away from direct heat or light. No other sample preparations are necessary for samples stored in pressurized containers. Avoid storage at temperatures greater than 25°C. Store pressure containers in accordance with the manufacturer's instructions.
9.5 It is recommended that a quality assurance (QA) sample similar to the reference material gasoline sample be run at regular intervals (see Fig. 1). An interval of once per week or after every 15 samples is recommended. The quantitation results use statistical quality control charts can track benzene. Other components of interest in the reference sample can be tracked in a similar manner. By monitoring these components over an extended period of time, the performance of the column and the chromatographic system can be determined.
