I analyzed organosulphur in water using HPLC and I am not quite sure what is the best calibration range that i am going to select
Hi,
Before to start you should determine LOD (limit of detection) and LOQ (limit of quatification).
- Calibration range should be 20%, 50%, 100% and 150% of target concentration of your compound.
- correlation coefficient higher than 0.990.
- Linear calibration range should cover the samples' results
Good luck.
if you looking for trace analysis..you may preferably prepare in low range concentration. however some compound may less sensitive to your instruments. what more important is your linearity given good r2 > 0.990
I am agree with the above answer, correlation coefficient higher than 0.990 may be OK.
It depends on your detection method and instrument sensitivity. You should try some of your standards and find the concentration range where the instrument response is linear (r2>.95) and then work in that range.
Are you intending to calculate prediction uncertainties? If not, you may consider nonlinear fits.
For selecting the calibration range, you should know the target concentration of the compound, I think the best calibration range is ca +/- 20 % the the target concentrations. If you do not know the target concentrations you can try to develop wider calibration range than you can estimate the concentration of the target compound; after this than you can develop calibration range +/- 20 % estimated concentration to determine the exact concentration. To express the linearity of the calibration curve, you cannot use "r" as sole parameter, other parameter such as Vxo, Mandel Test, F ratio etc must be determined. Please read e.g. P. Araujo, J. Chromatogr. B. 877, 2224-2234, or our chapters regarding Validation in: HG Brittain (Ed.) Profiles of Drugs Substances, Excipients and Related Methodology, Vol. 32 (Validation method of analysis by using Chromatography) and 37 (Validation method of Analysis-Updated 2011), Elsevier Academic Press, San Diego, New York
Hi,
Before to start you should determine LOD (limit of detection) and LOQ (limit of quatification).
- Calibration range should be 20%, 50%, 100% and 150% of target concentration of your compound.
- correlation coefficient higher than 0.990.
- Linear calibration range should cover the samples' results
Good luck.
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