Chemoluminescence GC Testing

[shaun78]

I am not sure if this is the proper subforum for this question, but here goes...

Our raw materials group needs to perform current EP testing on trolamine. The problem we are having is the impurity C testing, which requires a chemoluminescence detector. More specifically, we do not have this type of a detector on our GCs and we don't run this assay enough to make it worth purchasing the detector.

As a result, the choice has been made to contract the work out. Unfortunately, we have been unable to find a GLP laboratory in the states that is capable for performing this testing. Most contract labs have simply told us that they do not have chemoluminescence detectors either and clients are not demanding work that requires them.

So, the question: does anyone know of a GLP lab that is capable of performing this tesing (I have googled and asked previous contract labs --- none can do it)? It would be ideal to find a lab in the US that will do this testing, but if it needs to be sent back to europe for a lab to do it there, then so be it.

[krickos]

Hi

chemoluminescence detector??!!

Current EP states a MSD detector in SIM mode ,seems like a mistake see below:

Impurity C. Gas chromatography 2.2.28 Carry out the test under a ventilated hood, wear gloves and safety glasses.
Test solution. In a suitable distillation apparatus mix 100.0 g of the substance to be examined and 100.0 ml of ethylene glycol R and gently distil 10.0 ml under vacuum at a pressure not exceeding 1.3 kPa. From this distillate, distil 1 ml.
Reference solution. Dilute 25.0 mg of N-nitrosodiethanolamine R to 100.0 ml with ethylene glycol R. Dilute 5.0 ml of the solution to 50.0 ml with ethylene glycol R. Dilute 5.0 ml of this solution to 50.0 ml with ethylene glycol R.
Column:
— material: fused silica,
— size: l = 30 m, Ø = 0.25 mm,
— stationary phase: macrogol 20 000 R (film thickness 0.25 µm).
Carrier gas: helium for chromatography R.
Flow rate: 0.75 ml/min.
Split ratio: 1:15.
Temperature:
Time
(min) Temperature
(°C)
Column 0 - 2 180
2 - 8 180 → 240
8 - 25 240
Injection port 240
Detector 250

Detection: mass selective spectrometer set at 72 m/e or 91 m/e.
Injection: 3 µl; if necessary inject a blank between each injection.
Retention times: impurity C = about 20 min.
Limit:
— impurity C: not more than the area of the corresponding peak in the chromatogram obtained with the reference solution (25 ppb).

[shaun78]

The EP 6.8 supplement that is to be effective July 2010 has switched the trolamine detection for impurity C from a MSD to chemoluminescence. Prior to a few days ago you would be correct that the method was GC/MS.

Please correct me if I am wrong about this current change.

[krickos]

Hi again

I am afraid your right, the new method seems like a really messy one, apart from using a "odd" detector.

I belive at least Agilent sells a NCD with the dual burner option as required. Se below. Sadly I am unaware of any laboratory using it.


NCD Applications
In addition to detecting organic nitrogen compounds, the NCD responds to ammonia, hydrazine, hydrogen cyanide and NOx. With the introduction of the Dual Plasma Burner and Controller, the NCD now has an embedded nitrosamines option.


EDIT: If anyone would know if there is a scientific logic behind this new method and sample preparation (glas colum...SPE anyone ), I would like to know.