by Residual Solvents
Instrument:
Gas chromatograph equipped with static Head-space and FI detector.
Reagents:
Isopropyl alcohol (HPLC grade).
N, N-Dimethyl formamide (DMF)
Sodium sulphate (anhydrous) AR grade
Dichloromethane (HPLC grade)
Chromatographic conditions:
Column: A (0.53 mm x 30 m) fused-silica capillary column coated with a 3.0 µm chemically crosslinked G 43 stationary phase; and a (0.53 mm x 5 m) silica guard column deactivated with phenylmethyl siloxane.
G 43: 6% cyanopropylphenyl-94% dimethylpolysiloxane or equivalent.
Injection volume: 1 ml of gaseous phase
Detector: Flame ionization detector (FID).
Carrier Flow: 35 cm/sec.
Temperature:
Injector: 180°C
Detector: 260°C
Column: 40°C for 20 minutes, then heat rapidly to 240°C and hold at 240°C for 20 minutes.
Run time: 50 minutes.
Integration Parameters:
Slop sensitivity: 10
Peak width: 0.04
Area rejection: 1
Start detect: 0 minute
End detect: 50 minutes
Total run time: 50 minutes.
Head space conditions:
Set Points:
Oven temperature: 80°C
Loop temperature: 130°C
Transfer line temperature: 140°C
Event Times:
GC cycle time: 60 minutes
Vial equilibrium time: 45 minutes
Pressure time: 0.50 minutes
Loop fill time: 0.15 minutes
Loop equilibrium time: 0.05 minutes
Inject time: 0.50 minutes.
Note: Integrator parameters can be changed as required.
Test preparation: Finely grind the sample and transfer the whole contentinto a headspace vial, add 5 ml of DMF and about 1 g anhydrous sodium sulphate, mix well and seal it immediately.
Put the head space vial into the head space.
Standard solution A: Prepare 10 ppm/ml solution of Isopropyl alcohol in DMF.
Standard solution B: Prepare 10 ppm/ml solution of Dichloromethane in DMF.
Standard C: Pipette 5 ml of standard solution A and 5 ml of standard solution B in to a 50 ml volumetric flask and dilute with DMF to volume.
System suitability: Relative deviation of peak areas of 6 replicate assay solutions should not exceed 15%
Procedure: Chromatograph test solution, record chromatograms and determine peak retention times.
Calculation: Calculate the Isopropyl content and dichloromethane content in the sample.
