With the abolition of the Japanese Provisional Measures Law on the Importation of Specific Refined Petroleum Products in March 1996, the concentration of methanol, MTBE (methyl tertiary-butyl ether), benzene, and kerosene (equivalent to 14 times the total content of n-C13 and n-C14) was prescribed. Four different gas chromatography measurements are prescribed as analytical methods for these controlled components in JIS K 2536-1996 (Liquid petroleum products -- Testing method of components).
"Total components testing method by gas chromatography" is introduced below.
Analysis of Gasoline Components (GC)
A gas chromatograph (GC) measures the content of various components in a sample. The sample solution injected into the instrument enters a gas stream, which transports the sample into a separation tube known as the "column." Helium or nitrogen is used as this so-called carrier gas. The components are separated inside the column, and a detector measures the quantity of the components that exit the column. To measure a sample with an unknown concentration, a standard sample with a known concentration is injected into the instrument. The standard sample peak retention time (appearance time) and area are compared to the test sample to calculate the concentration.
