Chromatography Forum

Hello,
I would like to determine NMP in pharmaceutical product by HPLC. The method must be selective to solvents (ethanol, dymethylacetamide, aceton, isopropylacetate and acetic acid).
I used:
Column: Hyperclone ODS (150mm x 4,6 mm; 5mcm particles
Mobile phase: amonium dihydrogen phosphate buffer: 2-propanol: methanol=550500; pH=7,0
Unfortunately NMP coelutes with all solvents mentioned above.
(We tried also GC method, peak for standard NMP was excellent however NMP peak in the sample has bad tailing).

Has anybody any idea how to determine NMP by HPLC?
bye bye

Best bet with a "624" phase (USP: G43) for residual solvents by GC. You won't do those on a C18.

We have carried out estimation of NMP in Pharmaceutical products as per below given conditions.

COLUMN: IC Cation-SW
Size: 4.6 x 50 mm
Part.size: 5.0 µm
ELUENT: 10mM Nitric acid:5% Acetone
Flow: 1.00 mL/min
Temperature: 35.0°C
Pressure: 3.2 MPa
System: Metrohm Ion Chromatography system with Conductivity Detector.

In case you need anu further information please let me know.

Deepak Parab
MDML - India
deepak@mdml.com

What you wish to do is easy given the correct reversed phase conditions. see JChrom,977(2002)249 for a chromatogram of this separation as well as conditions.

Hello!
Since we have not conductivity detector (thank's anyway Deepak Parab) we have succeeded wit Bill's sugestion and have got very nice NMP peak.

Thank you very much
juju

I am pleased that it worked for you. Reversed phase separations can be done on most water soluble compounds. Some times a very retentive column is necessary as well as one that can be used with 100% water.