Abstract
Coupling of 2,6-dichloroquinone-4-chlorimide (DCQ) with tranexamic acid (TA) resulted in a greenish-brown colored complex which absorbed at lambda(max) = 670 nm. It was found that the color intensity of the coupling product changes with time. The present work was aimed at studying the kinetics of this absorbance variation as function of the time at room temperature so as to provide a new colorimetric method for the quantitative determination of TA. To this end, four kinetic methods were conducted and the corresponding calibration curves were constructed. Based on analysis of the correlation coefficients, the fixed time method proved to be the best one (R = 0.996). Nonetheless, the method appeared to suffer from lengthy time and lower sensitivity. Therefore, attempts were made to eliminate these drawbacks. Accordingly, the analysis was conducted using non-kinetically fixed time method with sample heating for three minutes. The obtained limit of detection (LOD) and limit of quantification (LOQ) for the non-kinetic method were found to be 24.01 and 80.04 mu g/ml, respectively. The proposed colorimetric method proved to have no significance difference with the official titrimetric method in terms of accuracy and precision.