A new ASTM International standard provides a test method for finding low concentrations of nitrosamines, a suspected type of carcinogen, in water. The standard (D8456) was developed by ASTM’s water committee (D19).
I could not find the details of the original ASTM methods(D8456) on the ASTM pages.
And according to the application note by Shimadzu, thirteen nitrosamines in water are measured using LC-MS/MS without any SPE pretreatment. For NDPhA, the precursor ion 170 is monitored. This method can also be employed for the waste-water containing high organic loads.
Thank you very much for the information. I am very interested in these topic.
About the analytical part: In my humble opinion and experience, it is not an analytical revolution. They use a loop to be able inject 300 uL. With HR-LC-MS equipment you can get to see those limits( inject much less volume and better peaks).
On the other hand, it appears that 0.05 ug/L is an insufficient limit…sometimes . In Germany, control limits for NDMA in drinking water are 10 ng/l
And the NDPhA looks really bad in LC MS… CG MS its the best option .
The method was purposely developed to be an alternative to existing approved EPA methods for nitrosamines in wastewater. The existing approved methods are GCMS full scan method 625.1 and GC-NPD method 607. Each of these methods have detection limits of about 0.1 ppb or higher. If the ASTM method was developed for lower concentrations, such as on a more sensitive instrument, then EPA would not consider it for approval because it would be too sensitive. As it is, the method is more sensitive than the existing EPA approved methods by an order of magnitude because the estimated detection limit is 0.01 ppb.
The method clearly states that it can be modified for greater sensitivity, such as using a more advanced instrument. Once it is approved by EPA, labs would be free to do so, and likely will. Because ASTM is a consensus standard organization, methods have to be developed to “not rule out” to the extent possible the instrumentation that an average user may have. Not all potential users have the most advanced instrumentation, so the method was developed to include a majority of instruments already installed.
The method does not attempt to analyze nitrosamines in drinking water because in the US, nitrosamines are not regulated, and Method 521 is not a regulatory method, so there is no means for the method to be considered for approval in drinking water. However, simply by updating to a newer model instrument, the lowest calibration standard can be lowered from 50 ppt as in this method easily to about 2 ppt or less (based on sensitivity specifications provided by the various instrument manufacturers).
We agree that some compounds do not perform so well by LCMS and do better by GC, however, as a consensus standard we have to respond to negative voters which sometimes means including analytes which are poor performers. The method will undergo an inter-lab study in the near future. It is my estimation that during the inter-lab study more sensitive instruments will be used, lowering the detection limit, and that the poor performing analytes, if they fail on reproducibility, would be rejected.