-
- Posts: 47
- Joined: Tue Dec 16, 2014 4:46 pm
Hello,
I am looking at three separate analytes from the same matrix. Right now I am having to run the samples using two different dilutions to measure all three compounds. In order to same time and also materials I would only like to run the samples once, but I'm unsure of the best way to do so while not reporting results outside of my calibration.
Current procedure for analyte 1
sample prep
~200 mg sample
20ml of meoh
50ul of sample / 950ul MeOH (1:20 dilution) into gc autosampler vial.
Final calculation is
reported analyte result (ng/ul)*20(1st dilution)*20(sedcond dilution)/1000/sx weight = analyte
Analyte 2 & 3 are ran on on gc without the second 1:20 dilution
Peaks for analyte3 2&3 are usually not present on the higher dilution chromatogram, and analyte one is on the lesser diluted chromatogram but in levels higher than my calibration curve.
The calibration curve for each analyte is
149.4 ng/ul
116.2 ng/ul
83 ng/ul
16.6 ng/ul
8.3 ng/ul
Results for analyte 1 with the 2nd dilution are on the right, results with out the 2nd dilution are on the left
17.23% 18.35%
17.02% 17.78%
18.28% 18.34%
16.25% 15.80%
27.21% 27.54%
20.35% 20.21%
22.46% 24.48%
22.67% 22.55%
21.22% 20.35%
26.30% 26.46%
19.86% 20.68%
For analyte one a typical result with the higher dilution is ~100 ng/uL
typical result without the additional dilution is ~2000 ng/ul
Analyte 2&3 are usually present in the lesser diluted run at about 12-20 ng/ul
at the higher dilution they are nearly always undetected.
The three standards I run come in individual 1 ml ampules at a concentration of 1mg/ml
Would it be feasible to make a calibration curve that would cover the entire range for all three analytes? Any suggestions or thoughts would be greatly appreciated.
I am looking at three separate analytes from the same matrix. Right now I am having to run the samples using two different dilutions to measure all three compounds. In order to same time and also materials I would only like to run the samples once, but I'm unsure of the best way to do so while not reporting results outside of my calibration.
Current procedure for analyte 1
sample prep
~200 mg sample
20ml of meoh
50ul of sample / 950ul MeOH (1:20 dilution) into gc autosampler vial.
Final calculation is
reported analyte result (ng/ul)*20(1st dilution)*20(sedcond dilution)/1000/sx weight = analyte
Analyte 2 & 3 are ran on on gc without the second 1:20 dilution
Peaks for analyte3 2&3 are usually not present on the higher dilution chromatogram, and analyte one is on the lesser diluted chromatogram but in levels higher than my calibration curve.
The calibration curve for each analyte is
149.4 ng/ul
116.2 ng/ul
83 ng/ul
16.6 ng/ul
8.3 ng/ul
Results for analyte 1 with the 2nd dilution are on the right, results with out the 2nd dilution are on the left
17.23% 18.35%
17.02% 17.78%
18.28% 18.34%
16.25% 15.80%
27.21% 27.54%
20.35% 20.21%
22.46% 24.48%
22.67% 22.55%
21.22% 20.35%
26.30% 26.46%
19.86% 20.68%
For analyte one a typical result with the higher dilution is ~100 ng/uL
typical result without the additional dilution is ~2000 ng/ul
Analyte 2&3 are usually present in the lesser diluted run at about 12-20 ng/ul
at the higher dilution they are nearly always undetected.
The three standards I run come in individual 1 ml ampules at a concentration of 1mg/ml
Would it be feasible to make a calibration curve that would cover the entire range for all three analytes? Any suggestions or thoughts would be greatly appreciated.
