Matrix elimination ion chromatography method for trace level azide determination in irbesartan drug.

Ultra-trace analysis of azide in complicated Irbesartan sample matrix is achieved by the in-line sample preparation technique. Sodium azide is the precursor of Irbesartan, which is used as an anti-hypertensive drug. Due to the toxic nature of sodium azide, reliable determination of azide in Irbesartan is necessary. Irbesartan when analyzed for sodium azide, as per the USP 31-NF26 method, gets adsorbed to the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h for each sample analysis. The new method developed overcomes the limitations of the USP 31-NF26 method. This method is validated for specificity, linearity, accuracy, precision, sample solution stability, and robustness as per International Conference on Harmonization guidelines. The relationship between peak response and concentration is found to be linear between 5 to 80 ng/mL of sodium azide, with the correlation coefficient (r(2)) of 0.9995. The limits of detection and quantification for sodium azide are 0.532 and 1.61 microg/gm with respect to the sample weight.