Parameter 1714.717-1649.138 cm-1 Linearity range (mg) 0.5-2.5 Slope 0.1869 Intercept 0.0150 Correlation coefficient (r) 0.9991 Regression 2502.67 (4.96) Lack of fit 2.48 (3.71)

*Values are reported as mean of three calibration curves generated on three consecutive days

Table 1: Linearity parameters for the determination of doxycycline* and summary of ANOVA.