Organic Residue Analysis in an Amphora from Tell el-Burak

Description

Technical info

GC and GC-MS analyses

The analysis was performed by Gas Chromatography (GC) and GC-Mass Spectrometry (GC-MS) using an Agilent Technologies 7890B GC System series chromatograph including Agilent Technologies Capillary Flow-Technology Three-Way Splitter Kit coupled to an Agilent Technologies 5977A MSD and FID. The analyses were carried out using helium as a carrier gas, with a split/splitless injection system (Gerstel Multi-Purpose-Sampler and Gerstel Cold-Injection-System 4), operating in the splitless mode with a purge flow of 3.0 ml min–1 and a constant pressure at the head of the column of 8.6667 psi. Samples were analysed using an Agilent J&W DB-5HT-column (15 m × 0.32 mm i.d.; 0.1 μm film thickness) and divided in two equal parts using 0.18 mm non-coated, deactivated silica capillary columns (0.66 m splitter-column to FID/ 1.52 m splitter-column to MSD) with the Three-Way Splitter Kit. The inlet temperature was ramped from 30°C to 240°C at 12°C s-1 (held isothermally for 5 min) and then increased to 350°C at 12°C s-1 (held isothermally for 10 min). The temperature of the oven was set at 50 °C for 1 min followed by an increase to 100°C at 15°C min–1, then to 240°C at 6°C min–1 and to 350°C at 10°C min–1 (held isothermally for 20 min). Mass spectra were acquired using electron ionization at 70 eV and obtained by scanning between m/z 50–950 in 1.562 s. The interface and the ion source temperatures were 300°C and 280°C, respectively. The temperature of the FID detector was fixed at 340°C. Mass spectra were matched against the National Institute of Standards and Technology (NIST) library, 2014 edition.