Regarding the query:
While plotting a standard curve, 10 mg potato starch is taken but while proceeding for samples, why do we use 20 mg of sample?
When we plot a standard, we are using potato starch which is pure amylose without amylopectin. So, when we pipette out 20,40, 60, 80 and 100 microlitre of sample, we assume it to be 20%, 40%, 60%, 80% and 100% pure amylose concentration in the series of tubes.
In case of samples, i.e, starch, it contains both amylose and amylopectin and it may also contain other impurities. So, if we take a 10 mg starch sample, we are practically assuming only 5 mg of sample for pure amylose. It gives a much lesser amylose estimate against the standard plotted with 1 mg/ml concentration. Hence, it has been standardized to use 20 mg starch sample considering the presence of amylopectin and other possible contaminants in the sample.
While plotting a standard curve, 10 mg potato starch is taken but while proceeding for samples, why do we use 20 mg of sample?
When we plot a standard, we are using potato starch which is pure amylose without amylopectin. So, when we pipette out 20,40, 60, 80 and 100 microlitre of sample, we assume it to be 20%, 40%, 60%, 80% and 100% pure amylose concentration in the series of tubes.
In case of samples, i.e, starch, it contains both amylose and amylopectin and it may also contain other impurities. So, if we take a 10 mg starch sample, we are practically assuming only 5 mg of sample for pure amylose. It gives a much lesser amylose estimate against the standard plotted with 1 mg/ml concentration. Hence, it has been standardized to use 20 mg starch sample considering the presence of amylopectin and other possible contaminants in the sample.
