Chirasil dex capillary column

During the embryo-larvae exposure test, solutions were collected for determination of PCB atropisomers at the beginning of treatment and 24 h post exposure. Water samples (1 L) were subjected to five liquid-liquid extractions with n-hexane (100 mL each time) in a separator funnel along with violent shaking. The n-hexane layer was transferred to heart-shaped flasks and concentrated to near-dryness by rotary evaporation (Shanghai Ailang Instruments, Shanghai, China) at 35°C. The concentrated solutions were then blown to dryness by nitrogen evaporation and the residue was again dissolved in 0.1 mL of isooctane for GC-MS analysis.
Twenty embryos or larvae samples in triplicate per treatment were weighed and homogenized with 0.1 mL isooctane using an electric homogenizer (Tiangen Biotech, China). After 20min ultrasonic extraction, samples were centrifuged at 5000 rpm for 10 min. The supernatant after 0.22-μm fiter was for GC-MS analysis.
An Agilent 7890A/5975C GC-MS system equipped with a Chirasil-Dex capillary column (25 m × 0.25 mm; I.D. 0.25 μm df) from Agilent was used for the purity and concentration determinations. The oven temperature was programmed as follows: 60°C for 2 min, 60–150°C at 10°C·min^-1 (held for 5 min), 150–180°C at 1°C·min^-1 (held for 22 min). SIM ions were m/z 360 (quantification ion), 362, and 358 [29 (link)].

Racemic PCB149 (99.9%) was provided by Dr. Ehrenstorfer GmbH (Germany). The racemate was separated and prepared on a Lux Cellulose-2 column (250 × 4.6 mm, 5 μm, Phenomenex, Torrance, CA) using an Agilent 1200 series high performance liquid chromatography (HPLC) instrument (Wilmington, DE) with 100% n-hexane as the mobile phase at a flow rate of 1.0 mL/min. The enantiomers (−)-PCB149 and (+)-PCB14948 (link) were repeatedly collected separately, concentrated to dryness using a nitrogen-evaporator (Hangzhou Allsheng Instruments company, China) and then dissolved in acetone (Fisher). The purities and concentrations of the isomers were determined by gas chromatography-mass spectrometry (GC-MS).
An Agilent 7890A/5975C GC-MS system equipped with a Chirasil-Dex capillary column (25 m × 0.25 mm; I.D. 0.25 μm df) from Agilent was used for purity and concentration determinations, and the oven temperature was programmed as follows: 60 °C for 2 min, 60–150 °C at 10 °C·min⁻¹ (held for 5 min), 150–180 °C at 1 °C·min⁻¹ (held for 22 min). The SIM ions were m/z 360 (quantification ion), 362, and 3587 (link). The purities of (−)-PCB149 and (+)-PCB149 were higher than >98.0%.