by
GOM » Sun Dec 20, 2015 9:24 pm
Hi
The only additional comments that I would make from when I used to use a similar prep for this analysis are
1. On removing the flask with solvent and EO (previously dispensed into a septum sealed vial from a lab cylinder) from the fridge I would allow a short time to allow the flask to come above the dew point to avoid condensation problems affecting the weighing. Humidity in the lab could be quite high.
2. After prep I would return the volumetric flask to the fridge but noticed that if I used a plastic stopper it would become loose on cooling but I overcame that by using a ground glass stopper.
3. Later I modified the method to SPME headspace with either single or multiple standard addition, spiking with a pre - prepared standard certified EO solution supplied in sealed ampoules from Sigma. Although multiple standard addition added to the overall analysis time, the savings in the standard prep and removing safety problems associated with dispensing from the EO cylinder balanced out. This method worked really well down to 1ppm. I have the details somewhere
4. Some samples may contain acetaldehyde, also C2H40 (e.g. nonionic detergent alcohol ethoxylates) and you need to ensure that your phase will separate that from EO to avoid getting a false positive result.
Regards
Ralph