The identification of oil chemical compounds was referred to mass spectral library HPCH2205.L, Wiley 7 NIST 05.L and NIST 05a.L database. The chromatograms from GC and GC-MS captured of existence sample oil constituents in terms of peak area count. For quantitative measurement, the percentage yield of extracted oil in wet weight basis can be calculated using Equation (1).
Yield (%) = Weight of essential oil recovered x 100%
Weight of fresh citrus peels
(1)
The weight of extracted material was based on fresh Kaffir lime peels. The density of Kaffir lime oil is in range of 0.871g/mL [21]. Therefore, the mass (in grams) of Kaffir lime oil can be derived from known volume (mL) x density of Kaffir lime oil (0.871g/mL).