Validation of the Method for Determining Caffeine Content in Green Tea with FTIR UATR

The FTIR UATR method for quantifying caffeine in green tea samples was validated. ATR (Attenuated Total Reflectance) , a technique for direct analysis without sample preparation, was employed. Caffeine was determined at peak absorption between 1600 and 1700 cm-1. Calibration using standard concentrations from 0 to 5% yielded excellent linearity with a correlation coefficient value of 0.9978. Precision, measured as % RSD (2.8369%), met the acceptable limit of 2/3 the Horwitz CV (4.5323). Accuracy was confirmed through spiking, resulting in a recovery of 100.3%, within the acceptable range of 95-105%. These findings demonstrate the suitability of this method for caffeine analysis in green tea samples.