Water Environment Federation (WEF) Discussion ForumsWater Environment Federation (WEF) Discussion Forumshttp://www.wef.org/TechnicalDiscussions/jfuller@wef.orgTue, 14 Oct 2008 07:12:49 GMT20http://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxNo problem. We bandied the idea about for a day - until we went in and really read the method.</P><P>So no, our lab will not be able to do this....</P><P>Ken</P><P><A href="mailto:aldri7@comcast.net">aldri7@comcast.net</A>Wed, 14 May 2008 14:20:46 GMTaldri7http://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxI'm sorry if I sent anyone on a wild goose chase. I hadn't thought about other peoples need for EPA approved methods. The samples we are planning to run are not permit required and thus they do not need to be run by an EPA approved method. The samples are part of an additional project we are involved in and the persulfate method is approved for this particular project.</P><P>We run TKN/TKP by block digestion on our plant samples.</P><P>LynnTue, 13 May 2008 17:43:08 GMTLynnhttp://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxMore to the point (as I read this further) - is there any alkaline persulfate digestion method (for both TP and TN) that is approved for NPDES compliance monitoring and safe drinking water act monitoring?</P><P>Ken</P><P><A href="mailto:aldri7@comcast.net">aldri7@comcast.net</A>Tue, 13 May 2008 17:31:05 GMTaldri7http://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxThis alkaline persulfate digestion is not the same as the one in standard Methods, 20th edition, according to the report. It would seem to be more applicable to the types of samples we analyze (our lab is currently also looking at combining TKN and TP analysis into one digestion). But it is not an approved method, so I don't see how we could use it. </P><P>Is there an EPA/SM approved alkaline persulfate method that will analyze both TN and TP together and can be run on acidified freshwater samples?</P><P>thanks,</P><P><A href="mailto:aldri7@comcast.net">aldri7@comcast.net</A>Tue, 13 May 2008 17:02:30 GMTaldri7http://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxOoops!!!</P><P>That report number is 03-4174Tue, 13 May 2008 14:04:40 GMTLynnhttp://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxWe are just embarking on the adventure of trying an autoclave method for total nitrogen. We plan to follow the alkaline persulfate method that was evaluated by the USGS as an alternative to TKN. We found it as Water-Resources Investigation Report 0.-4174.</P><P>We currently run TKN by block digestion and are enticed by better detection limits, higher sample through-put and the ablility to run TP concurrently.</P><P>We are hoping to make our first attempt in the next few weeks.</P><P>Hope this helps...Tue, 13 May 2008 14:03:38 GMTLynnhttp://www.wef.org/TechnicalDiscussions/Topic9067-15-1.aspxI am trying to find information on how to perform a digestion for TKN using an autoclave. Can anyone tell me if this is possible? Any information is greatly appreciated.<br><br>Thanks,<br>Andy<br><br>Tue, 06 May 2008 14:08:33 GMTdiatomguru