New proposed GC-NPD method for nitrosamines

Check out this nice paper recently published (Jan. 6, 2022!) by @Jinjian and colleagues from Merck about:

“Full Evaporation Static Headspace Gas Chromatography Method with Nitrogen Phosphorous Detection for Ultrasensitive Analysis of Semi-volatile #Nitrosamines in Pharmaceuticals”

The authors proposed a new headspace sampling technique (Full Evaporation Static Headspace (FE-SHS) for the analysis of nitrosamine in solid dose pharmaceutical products, which reduces extraction time and improves the extraction efficiency and thus sensitivity. They compared it to Traditional Static Headspace (SHS) sampling.

Link for the article: A Full Evaporation Static Headspace Gas Chromatography Method with Nitrogen Phosphorous Detection for Ultrasensitive Analysis of Semi-volatile Nitrosamines in Pharmaceutical Products | SpringerLink

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Dear Amanda,

The article is very informative however, one doubt is that the comparison done is between DMSO and diluent containing IPA+Pyrogallol+Phosphoric acid so the matrix is completely different. The comparison should be done between,

  1. 1ml Vs 50 microliter of DMSO or
  2. 1 ml Vs 50 microliter of diluent (IPA+Pyrogallol+PA)
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Hi Nitish461990,

You cannot add 1 mL IPA as the vial will be over pressured.

The purpose of the solvent is to inhibit in situ nitrosation, and allow for quantitation using external standard. The sensitivity is calculated relative to the sample amount.

Thanks,
Jinjian

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Hi Amanda, thanks for sharing. I think this is a great development in the context of a more cost effective method for the QC environment compared to LC-MS and GC-MS. I would not say it is necessarily a simpler method for QC due to the headspace sample preparation and need for the inhibition reagents. A lot of care is required to make sure the method is robust… But great potential. Cheers. Tony

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Hi Tony,

I thought the biggest advantage of this method is its simplicity in sample preparation. You just need to grind the tablet into powder, same as any other methods, transfer a portion to the headspace vial, add diluent, cap and crimp for analysis. You can analyze 100 samples per analyst per instrument if needed. Sample extraction for GC or LC analysis is quite labor intensive especially for large volume products like metformin, sartans etc.

Regards,
Jinjian

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Hi Jinjian, apologies for the delayed reply, been busy with nitrosamines :grinning: You make a valid point on the capacity of the method. It would be great to discuss this with you in more detail, as I am very keen to see how we can simplify the methods we provide to the QC environment. I believe you have also been discussing this with my colleague Mark Harrison? Best Wishes. Tony