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- Posts: 8
- Joined: Sat Mar 31, 2018 11:23 am
I have some confusion in sample preparation and calculation. I am asking question giving two situations
situation 1: During Benzoic acid analysis of juice, 5 ml of juice sample is taken in 25 ml vf and volume is made up to the mark with buffer. Aliquot of the final solution is injected into hplc system. Suppose 8 ppm benzoic acid is obtained from hplc in sample aliquot. Then the benzoic acid in the juice is calculated as
=8*25/5
=40 mg/L
situation 2: During Benzoic acid analysis of tomato sauce(which is semi solid material), 5 g of sauce sample is taken in centrifuge tube and 25 ml buffer is added into 5 g sauce. Aliquot of the final solution is injected into hplc system. Suppose 6 ppm benzoic acid is obtained from hplc in sample aliquot. Then the benzoic acid in the sauce is calculated as
=6*25/5
=40 mg/kg
My question is, what is correct calculation for situation 2, where sample is not completely dissolved in buffer? What is the correct dilution factor in calculation for situation 2?
is it 6*25/5
or 6*(25+5)/5
or 6*{25+(5-Moisture content of 5 g sample)}/5
Or we have to use weight of total solution/ weight of sample as dilution factor?
what is the accurate way of calculation for analysing those semi solid samples which are not completely dissolved in buffer?
thanks in advance