Aditi Sh: Have you asked your professor for assistance? Please contact an experienced, professional chromatographer for the most applicable advice for YOUR sample. Sample preparation is worked out during the development of the HPLC method for analysis. The person who is in charge of, and trained to operate the LC-MS instrument should be the person to speak with. They should be able to suggest to you the most appropriate solvents to use for your sample once a method of analysis has been developed. *Sample Prep: To remove the cells from the sample, centrifuge the mixture at 4C, then aspirate the supernatant into a clean vial (wash with ethyl acetate). Dissolve fully in the mobile phase and filter before use. Use an HPLC system with full scanning DAD plus MS, in-line, for analysis.

To prepare samples efficiently for LC-MS analysis of products formed during styrene degradation, collect the culture supernatants from the bacterial growth medium by centrifuging the culture broth at 21,880× g for 20 minutes. Use a dual-solvent system for the LC-MS analysis, with solvent A (50 mM phosphate buffer, pH 2.5) and solvent B (acetonitrile), initiating the gradient at 100% A (0–3 minutes), gradually shifting to a 50:50 mixture of A and B (3–6 minutes), maintaining between 6 and 7 minutes, and subsequently shifting back to 100% A (7–13 minutes). Use an 18-MS-II column operated at 30 °C with a flow rate of 1.2 mL·min−1, connected to an ultraviolet absorbance detector (SPD-20AV; Shimadzu) set to 254 nm for product concentration determination, and use the resulting chromatograms to identify and quantify the products formed during styrene degradation by comparing the retention times and peak areas of the detected compounds with those of known standards.