A: Higher molecular weight compounds that have a noticeable scent. Vanilla would be a possibility.

A: We have not determined an analytical detection limit. However, since we are performing the analysis on the headspace above the sample, it is difficult to determine the true concentration in the sample.
The TBA concentration in the headspace is dependent on how well TBA is desorbed or emitted from the sample.

A: To date, we have not studied the transmission of TBA through various plastics.
Consequently, we do not have any data.

A: The concentration measured from the SPME fiber in the air is dependent on the TBA air concentration and the length of time the fiber is exposed to the air. The measured concentration would need to be adjusted for the exposure time.

A: Based on the information in the literature, there is no allowable limit because TBA is non-toxic.

A: TBA is a highly volatile compound that can permeate through the packaging and the plastic. These are porous materials. Since TBA has a very low odor threshold, a concentration greater than 50 parts per quadrillion can be sensed olfactorally.

A: The people performing the sniffing are chemists who have many years of experience in analytical chemistry, along with a significant amount of exposure to aromal odor analysis.

A: We have used this type of testing procedure with many companies to determine tba. However due to confidentiality, we cannot specify the companies that have employed the services of Microanalytics.

A: One curve represents the analytical result from the gas chromatograph. While the other curve represents the aromagram generated by the scientist at the sniff port. The combination of these two anlaysees is what makes our technology so unique and accurate.

A: Since the mass spectrometer signal is at the instrumental background, initial identification of TBA occurs with the olfactory detector (nose).
The concentration of the TBA in the headspace is below the detectable level of the mass spectrometer.
However, the scientist can focus on the area where the off-odor occurs.
In order to confirm the identification, the concentration of the compound needs to increase.
This can be performed through longer collection times, heartcutting in the gas chromatograph, cryotrapping and backflushing the column.

A: Quantification does require the dilution of certified standards and preparing quantitation curves. Since we are mainly dealing with headspace make-up, we are only seeing that portion of the overall compound that has been released into the headspace.  The total makeup of the sample needs to be considered when quantification is desired.  This consideration takes into account the environmental conditions under which the sample is being evaluated. The process is very time consuming and may have to be repeated on a daily basis.
Given the low odor threshold of TBA, and the general opinion that TBA is not a toxicity risk at these low levels, we lean toward the idea that the initial concern was the presence of the TBA odor, and that concern will not go away until the odor goes away.  Is quantification really necessary? 

A: Using a SPME fiber allows the sample from the headspace to be preconcentrated prior to analysis in the gas chromatograph.  The length of time the fiber is exposed to the headspace can be increased.  In odor analysis, the priority goes to identifying the compounds of interest. Preconcentrating the headspace sample increases the chance of collecting enough of the odorous compounds in the headspace so that the compound can be identified by the MSD.

A.To increase the sensitivity of the GC/MS analysis, the concentration of the compound of interest needs to increase.  This can be performed through longer collection times, increase selectivity through heartcutting the overall sample and sending those regions of interest to the detector, cryotrapping, and backflushing the column. When the compound has been identified the MSD can be switched to Selective Ion Monitoring.

A: Based on the information that we have found, there is no allowable limit because TBA is non-toxic.

A: Samples can be submitted for analysis at this time. 
Please contact MOCON (763) 493-6370 and request that a sales representative, for your area, contact you. The sales representative will arrange for a conference call to discuss your analytical needs. The scientists involved with this type of analysis will be part of the conference call to discuss the types of samples to be collected, and provide insight on how the samples should be handled, etc.  This will allow us to provide an accurate price quote for you analysis.