Quantitative analysis of samples using 3rd order polynomial regression. All samples are first corrected by the mean of the blank group measurements. The standard data points are plotted (concentration vs. corrected measurement) and 3rd order polynomial regression is applied to these points. The concentrations of the unknown samples are determined from the fit. To avoid ambiguous results (which can occur from turning points) extrapolation is not used with this method, i.e. concentration values will only be found within the range of the standards.

Quantitative analysis of samples using quadratic regression. All samples are first corrected by the mean of the blank group measurements. The standard data points are plotted (concentration vs. corrected measurement) and quadratic regression is applied to these points. The concentrations of the unknown samples are determined from the fit. To avoid ambiguous results extrapolation is not used with this method, i.e. concentration values will only be found within the range of the standards.