2.1 Sample, Chemicals and reagents
Non-refined, organic PSO from pumpkin seeds roasted at ~110 °C (Bio-Zentrale Naturprodukte, Ulbering, Germany) was purchased in a local supermarket in Stuttgart (Germany). Potassium hydroxide, toluene (99.9%) and hydrochloric acid (concentrated, 32%) were bought from Carl Roth (Karlsruhe, Germany). Methanol (> 99.8%) and n -hexane (> 95%) were ordered from VWR Chemicals (Darmstadt, Germany). Pyridine, ethyl acetate (both distilled before use), trifluorotoluene (benzotrifluoride, BTF, > 99%) and silica gel 60 were from Sigma-Aldrich (Steinheim, Germany). Acetonitrile (99.9%) was bought from Th. Geyer (Renningen, Germany). The trimethylsilylation reagent (99% N,O-bis(trimethylsilyl) trifluoroacetamide and 1% trimethylchlorosilane) was purchased from Supelco (Bellefonte, PA, USA). The internal standard for GC/MS measurements, 5α-cholestane (> 98%), was from Acros Organics (Geel, Belgium). Deuterated chloroform (CDCl3, 99.8%) was ordered from Deutero (Kastellaun, Germany).