We see acetone ~40ppm in wastewater and production plant don't know where is it coming from? FYI: Our product contains IPA (70% to 80% )with ~50ppm acetone as an IPA impurity based on supplier certificate of analysis. The wasted drug product (very small amount of waste) gets diluted with ~1000 gallons of water in spent tank, so acetone should not be detected in wastewater by GC MS. We found 10 to 50 ppm acetone in wastewater samples from the spent tank. So where is acetone coming from, and why acetone value is inconsistent in wastewater samples? Any suggestions where to look for the ghost acetone source? Can bacteria produce acetone in wastewater or IPA oxidizes to acetone?

Possible contamination of the laboratory glassware being used to analyse the sample? We had something similar in my first job out of university in a quality lab checking high street pharmaceutical products. Acetone kept showing up on the gas chromatograph (struggling to spell that after all these years!) and we traced it to the lab tech using acetone to dry her glassware. She stopped using it and the peak disappeared. Of course if you are not using acetone then it won't be that!

Sorry if I sound I'm beating the same drum all the time but have you confirmed the amount of acetone via different methods and/or via an external lab? If you're using GCMS then I would guess there is little room for doubt, but wet bench chemistry and old fashioned GC can be misled by other contaminants giving a false positive.