Hi,
If we trace the calibration curve of gallic acid or quercetin, one never obtains a straight line which does not pass through the origin (C = 0 for an absorbance = 0). This absorbance (C = 0) due to what? (If neglected manipulation errors)
Thank you.
It is possible that your medium in itself absorbs at the wavelength and you simply have to subtract this absorbance from the sample values where you have added your compound. Also check on your cuvettes or plates you are using.
It must be an error and as Mr Stanley points out it must be the medium absorbs the wavelength. If possible you can try with other medium and see the result.
Hope this helps.
Interpretation of zero (0) as part of the vocabulary is indeed nothing, but when the same is related in terms of numerical figures, '0' is a figure that may allow medium absorption to take place, hence the seemingly the positive absorption figures. As earlier suggested, try the negative figures and verify whether medium absorption is taking place or not. If so, then check the cuvettes or plates that are being used.
1. solvent can absorb itself, 2. it is necessary to check purity and size of cuvettes 3. it is to establish % of absorption from absobtion of sample. Probably You can ignore this absorption
solvent can absorb itself (quite right). in this case, Solvent is host and "acid" is guest (both absorb together at the same wavelength but their absorbtivitys is quite different ) Subtraction this positive absorbance is easy to understand, which is also similar "tare" on the balance when u weigh the liquid chemical.
However, Note subtraction or ignoreing, which depends on percentage of this intensity (positive absorbance value) comparation to max intensity (corresponding to C=max).
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