Hi to all!
Please, Someone can give me one good method for use in determination of residues of chlortalonil in food samples!
At the moment, we tryed to use a GC-ECD, to do that, but the results are not so good.
Thanks for your help, in advance!
By Consumer Products Guy on Tuesday, August 24, 2004 - 07:48 am:
We've used HPLC:
Make up standard in ACN, extract sample with ACN.
HPLC Configuration Parameters
Column Keystone Betasil C18 150 mm x 3.0 mm i.d. 3u column (Keystone P/N 153-70101) with 10 mm 3u Betasil C18 Javelin guard cartridge (Keystone P/N 887015-701-P)
Mobile phase: 70% ACN, 30% of 0.4% Acetic Acid in water
Flow Rate 0.35 ml/min
Run Time (min) 13
Injection Volume 1 ul
Column Temperature 30*C
Detector wavelength (nm) = 260
Retention time about 5 -6 minutes
By UMAchem on Wednesday, August 25, 2004 - 03:19 am:
Thanks for your help!
I have another question.How you make the extraction of Chlortalonil?
The method i use to do that for GC may be different.
Thanks again for your help!
By Consumer Products Guy on Wednesday, August 25, 2004 - 08:42 am:
Ours were paper samples; we used ultrasonic mixing for 30 minutes.
By UMAchem on Thursday, August 26, 2004 - 01:42 am:
But i have one more question. I need to know the amount of sample used in the extraction, the volume of solvent used, the solvent used and the amount of extract in the final of extraction.
When i used the GC-ECD for determination of chlortalonil in tomato, i observed in the signal a possible degradation of chlortalonil, you see the same in HPLC?
Thanks in advance for your help!
By Consumer Products Guy on Thursday, August 26, 2004 - 08:42 am:
Deliver 0.05 g of chlorothalonil into a tared, 100 ml volumetric flask (nearest 0.0001 g). Add 50 ml of acetonitrile, cap, and sonicate for 10 minutes. Following sonication, swirl the flask and ensure that the chlorothalonil is totally dissolved. Allow the solution to cool to ambient temperature and dilute to volume with acetonitrile. Stopper and mix thoroughly. Into a 50 ml volumetric flask, deliver 1.00 ml of above solution. Dilute to volume with acetonitrile. Stopper and mix thoroughly. For paper samples we used 0.5 g paper and 20.0 ml acetonitrile. We don't see any degradation or impurity peaks by HPLC.
By UMAchem on Friday, August 27, 2004 - 02:49 am:
Thanks again for your help!
By UMAchem on Friday, August 27, 2004 - 02:54 am:
Can you tell me the Limit of quantification (LOQ) and Limit of detection (LOD) of that method in ppm.
Thanks again in advance for your precious help.
By Consumer Products Guy on Friday, August 27, 2004 - 07:24 am:
We were looking for 200-2000 ppm, didn't need to try to get better limits.
By UMAchem on Monday, August 30, 2004 - 03:09 am:
Thanks for ypur help, again!
But i think that method can't be used with me, cause we work in residues of pesticides with LOQs lows than 0.01 ppm. Thanks again for your help!