Turbovap evaporator

Raw wastewater samples collected from local wastewater treatment works, were filtered using GF/F glass microfibre filter 0.75 µm (Fisher Scientific, UK) followed by a solid phase extraction (SPE) using HLB Oasis® cartridges Water, UK) to reduce the matrix effect and to concentrate each sample by 400fold. SPE procedure was as follows: 100 mL of filtered wastewater were loaded onto Oasis HLB cartridges, which were preconditioned with 2 mL MeOH followed by 2 mL H2O. After loading, the cartridges were dried for 30 min and analytes were eluted with 4 mL MeOH. Extracts were then dried under a gentle nitrogen stream using a TurboVap evaporator (Caliper, UK, 40•C). Dry extract was then reconstituted in 250 µL 80:20 H2O:MeOH, transferred to polypropylene vials and analysed using Dionex Ultimate 3000 HPLC coupled with a Bruker Maxis HD Q-TOF according to the procedure described above.
After analysis, data extracted from the Bruker system were processed with MetID software (Advanced Chemistry Development, Inc., ACD/Labs, UK) in order to predict metabolite structures. However, the software predicts a large number of possible metabolites, of which a rather small number is actually observed in in vitro experiments. We therefore developed a systematic workflow as presented in Figure 1 to limit false positive measurements.

Seven pooled urine samples were collected from a UK festival event. They came from five different urinals sampled on three different days. Solid phase extraction (SPE) was performed on pooled urine samples using HLB Oasis® cartridges Water, UK) to reduce the matrix effect and to concentrate each sample by 4-fold. SPE procedure was as follows: 2 mL of pooled urine were loaded onto Oasis HLB cartridges, which were preconditioned with 2 mL MeOH followed by 2 mL H2O. After loading, the cartridges were dried for 30 min and analytes were eluted with 4 mL MeOH. Extracts were then dried under a gentle nitrogen stream using a TurboVap evaporator (Caliper, UK, 40•C). Dry extract was then reconstituted in 500 µL 80:20 H2O:MeOH, transferred to polypropylene vials and analysed using Dionex Ultimate 3000 HPLC coupled with a Bruker Maxis HD Q-TOF according to the procedure described above.