2.7. Calibration curve
Calibration curves were obtained by injecting 10 ll of solution
from each of the above said standard solutions of the samples.
From the calibration points, a calibration curve based on the ‘least
squares’ methodology was generated,20 however, typically the calibration
curve generated using an ELSD is sigmoidal or exponential21
including fructose, galactose, glucose, sucrose, maltose,
lactose, and raffinose which produced second order polynomial
curves. Further, to convert the calibration curves from polynomial
to linear, the log 10 of the peaks area and calibration concentrations
were calculated.22 The parameters of the second-order polynomial
calibration curves using acetonitrile and H2O as mobile
phases were similar for all. Even though the calibration curve
parameters were close when calculated as a polynomial curve,
the log-transformed linear parameters were closer between mobile
phases and therefore a linear calibration curve applied to the logtransformed
data is preferred.