u can try this
Posted: Wed Nov 15, 2006 11:56 am
Hi, Murshad
i have done lots of work on USP mehods. i feel u should change the way you are preparing standard solution.
i dont know exactly what way you are preparing your solutions.
i am here suggesting you the technique which i do follow. right ?
well USP haven't mentioned the dilutions and all in their protocol. They have just mentioned the concentrations in which each solvent is suppose to be present in your final solution that you are going to fill up in the head space vial. isn't it ? U can try the procedure which is mentioned below :
solution-A preparation :-
weight 0.6 gm chloroform + 0.8 gm Trichloroethylene in 100 ml volumetric flask containing 30 ml of water and dilute it upto 100 ml with water.
Stock solution preparation :-
weight 0.6 gm Dichloromethane + 0.38 gm 1,4-dioxane + 10 ml of solution-A in the 100 ml volumetric flask containing 30 ml water and dilute it upto the mark with water.
Standard solution preparation :-
Take 0.2 ml of Stock solution to 100 ml volumetric flask contaning 30 ml water and dilute upto the mark with water.
Sample preparation :-
100 mg sample in 20 ml head space vial + 5 ml water ---- crimp the vial
Sonicate your solution -A for sufficient time so that your water immiscible solvents can get miscible in water.
Keep your injection speed 1 ml/second and fill speed 500 ul/second.
I hope this will solve your problem. Try it out and don't forget to add 1 gm sodium sulphate to each of the blank, standard and sample vial.
ok then try this and then reply me..bout your results.
ok cu and take care.
bye
regards,
Dhruvil
i have done lots of work on USP mehods. i feel u should change the way you are preparing standard solution.
i dont know exactly what way you are preparing your solutions.
i am here suggesting you the technique which i do follow. right ?
well USP haven't mentioned the dilutions and all in their protocol. They have just mentioned the concentrations in which each solvent is suppose to be present in your final solution that you are going to fill up in the head space vial. isn't it ? U can try the procedure which is mentioned below :
solution-A preparation :-
weight 0.6 gm chloroform + 0.8 gm Trichloroethylene in 100 ml volumetric flask containing 30 ml of water and dilute it upto 100 ml with water.
Stock solution preparation :-
weight 0.6 gm Dichloromethane + 0.38 gm 1,4-dioxane + 10 ml of solution-A in the 100 ml volumetric flask containing 30 ml water and dilute it upto the mark with water.
Standard solution preparation :-
Take 0.2 ml of Stock solution to 100 ml volumetric flask contaning 30 ml water and dilute upto the mark with water.
Sample preparation :-
100 mg sample in 20 ml head space vial + 5 ml water ---- crimp the vial
Sonicate your solution -A for sufficient time so that your water immiscible solvents can get miscible in water.
Keep your injection speed 1 ml/second and fill speed 500 ul/second.
I hope this will solve your problem. Try it out and don't forget to add 1 gm sodium sulphate to each of the blank, standard and sample vial.
ok then try this and then reply me..bout your results.
ok cu and take care.
bye
regards,
Dhruvil