Determination of 4- and 5-Ring Polycyclic Aromatic Sulfur Heterocycles in Tea Leaves

Abstract

Polycyclic aromatic sulfur heterocycles (PASH) were identified and determined in 15 kinds of tea leaves and 2 kinds of healthy food by capillary FPD/GC and capillary GC/MS. Benzo [b] naphtho [2, 1-d] thiophene, benzo [b] naphtho [2, 3-d] thiophene, chryseno [4, 5-bcd] thiophene and benzo [2, 3] phenanthro [4, 5-bcd] thiophene were identified in tea leaves. Alkyl (methyl, dimethyl) derivatives of benzonaphthothiophenes were also identified using mass chromatography (m/z=234, 248, 262). Samples produced in foreign countries contained higher levels of PASH (258≥MW≥234) and PAH (252≥MW≥228) than Japanese ones. The ratio of total-PASH to total-PAH was approximately within the range 0.1-0.3.