Chromatography Forum

In order to meet the TNI requirements for 8260, and 624; we have to run 12 sets of PT samples twice a year (you have to pass for each matrix and each compound). This is costly, time consuming and in my opinion not necessary. If you are able to successfully analyze one PT sample of a representative compounds of interest, then that should satisfy the requirement. I like to know what to you think.

That is one argument for going to ISO, one PT per year rather than two.

Yeah, that sounds a bit excessive. If you pass for benzene in wastewater, I think you're good for drinking water, etc. My gripe is that you have to hit certain detection limits regardless of whether you ever need to do that in your actual projects. I've seen PTs help to shine a spotlight on areas we could improve, but I've also been frustrated sometimes.

Depending on where you get them, I think the hardest part about passing tends to be filling out the stupid reporting sheets (lots of compounds with very similar names written in a small font in an unhelpful order). The worst was when the analyst messed up their addition... m,p-Xylene was reported right, o-Xylene was reported right, but the combination had an extra zero appended to the end of the result. I mean, how do you write up a "corrective action" for that?

I think TNI/NELAC has some good resources, and I understand they have a difficult task. There are probably rules that look stupid to me but would make sense if I knew more. I assume everyone there is well intentioned. But I'd be interested in knowing more about what incentives and interests the different stakeholders in TNI/NELAC have. Not just for people selling PTs or columns or inspections/certifications or whatever. If you're a Big Rich Analytical Lab and you get to vote on whether all labs should be required to do X annoying hoop-jumping thing that you have the staff and equipment to do but small competitors might not)... well that might tilt your perspective a little.

[Edit - I should add that I don't know if anyone actually stands to sell more stuff depending on what kind of standards TNI comes up with. I'm not trying to accuse anybody of anything.]

In order to meet the TNI requirements for 8260, and 624; we have to run 12 sets of PT samples twice a year (you have to pass for each matrix and each compound). This is costly, time consuming and in my opinion not necessary. If you are able to successfully analyze one PT sample of a representative compounds of interest, then that should satisfy the requirement. I like to know what to you think.

For our TNI we run 8260/624 water PT twice per year, and 8260 soil PT twice per year, since there is no soil matrix under 624.

For Drinking water it is a set of Regulated, Unregulated and THM PTs twice per year under 524.2 and a EDB/DBCP twice per year as 524.3SIM.

Not sure if you have other matrix to make it up to 12 sets, but those are ours for the volatiles lab.

The naming is the worst part and it is based on the EPA requirements, not so much TNI. Drinking water branch wants it reported as Methyl Chloride and 1,1-Dichloroethylene and Waste water branch wants it reported as Chloromethane and 1,1-Dichloroethene, as an example.

I am not big on having a lot of laws and regulations but could we at least get one that forces all branches of EPA to use the same naming pattern? They can't even agree on limits for tuning ion ratios in BFB and DFTPP for goodness sake. Then there are the units, our drinking water branch wants everything reported in mg/L so I have a detection limit for Silvex herbicide of 0.0000075 mg/L can't say that isn't difficult to not misplace a 0 on

I have a detection limit for Silvex herbicide of 0.0000075 mg/L can't say that isn't difficult to not misplace a 0 on

I think I'd try reporting in scientific notation just to be a brat.

I have a detection limit for Silvex herbicide of 0.0000075 mg/L can't say that isn't difficult to not misplace a 0 on

I think I'd try reporting in scientific notation just to be a brat.

Our lead metals chemist says scientific notation confuses her.

I only have to pass 2 PTs per year for method 300.0. They always give us easy ones though. Our nitrite is always a pure nitrite. If they gave us a nitrite with 1000 mg/L chloride we probably couldn't analyze it with our current procedure. We only could do it if we calibrated much lower so we could dilute the sample to get the Cl level down. That would mean doing additional LOQ studies which take too much time. I had a real world sample with 5000 mg/L Cl in it last month and I rejected the nitrite test.