Chromatography Forum

We got dinged on our last audit for not having second source standards
for 525.2. Is it just me or does everyone have trouble with this issue. We use Ultra Scientific DWM 525K-C kit with an additional custom mix from Spex to fill out our compound list. After going cross eyed from looking at catalogs only to find most every manufacturer has different compounds in their mixes. By the way our auditor said we must have every compound in our second standard as in our primary!
Why do I feel we are being required to re-invent the wheel here? All the manufacturers we use are ISO certified, isn't that enough?
So much for the rant! How do you folks deal with the second source issue.
I'm rapidly running out of hair!

Thanks
John

John,

Most of the vendors will allow you to purchase standards from two different lots. This is usually sufficient to meet your accreditation requirements.

Greg Pronger

In the UK the main auditors (UKAS) are starting to move away accepting second lots of standards from the same suppliers. They are really pushing for second suppliers.

We usually get the suppliers to make custom mixes for us. Expensive yes, but we try to get good deals for a 12 month supply.

Rich

That would make things more difficult. Thw whole secondary source issue, if you think about it too long can make one's head hurt.

For instance, the likely reason for not accepting two lots from the same manufacturer is obviously that if they make a mistake on the first lot, the possibility of the same error on a second lot; say the wrong isomer utilized.

The problem is that many of these standard supply companies are not manufacturing the materials, but are simply purchasing from one of the few companies that are actually performing the synthesis. So, how do we ensure that we don't have two different companies using manufacturer XYZ's wrong material that was sold to both?

Separately, there are a few companies that have set up cooperatively to prepare matching solutions. Off-hand I'm not sure who they were, but I do recall seeing the program.

We had similar problems with finding primary and secondary standards for 552.3 (haloacetic acids by ECD-GC). There were ten different analytes, and no vendors had a complete set of all ten, and none offered the same partial sets, or even uniform concentrations. The only solution was to request custom mixes, which we were able to do without too much trouble.
Hope this helps!
J.Clark
AZDHS

Thanks, I've found that my suppliers can create custom mixes with different lot numbers that should satisfy my auditor.
A follow up question. I was reading the NELAC standards ( yawwwwn) and it states that a second source must be run for every initial calibration. We usually recieve 3 sets of standards at a time and they usually have the same lot numbers. If I ran an initial calibration in Jan. using lot A and tested it with a SS then in March if I ran another initial calibration using fresh set of lot A would I have to run a SS, that I tested lot A in Jan??

We run the second source every time we recalibrate. Besides verifying the standards themselves, my perspective on the requirement is we're also verifying the dilutions we're making from the standards.