The best way is to use HPLC or GC (gas chromatography). GC has some advantages because of better selectivity: not many E. coli metabolites are volatile as acetic acid (do not forget to acidify the supernatant to covert acetate to free acid, otherwise acetate at pH 7 is NOT volatile). The protocols for both methods (HPLC and GC) are very well established, I can provide ref. If your lab does not have HPLC/GC, then you can try specialized colorimetric reactions (browse through the Sigma analytical part where numerous kits are listed for the price 100 to 500 USD.
Hi, I saw this answer from a LONG time ago and I'm hoping that you would still be able to help. I can't find any procedure for analysis of acetate by GC or C18 HPLC online. Do you still have these SOPs at your disposal to provide?
The simplest protocol for HPLC/C18: 0.05 N H2SO4 as mobile phase, constant pumping rate 0.3 ml/min. Ace will show up after 4-5 min. The best detector among the widely used: RI (refractive index). But you can get decent data with photoarray or UV detector at 200-210 nm wavelength.