Determination of Hydrazoic Acid and Sodium Azide in Workplace Air by Ion Chromatography with Suppressed Conductivity Detection

• • Achieved baseline separation of azide (N3−) from nitrate (NO3−) using a Dionex IonPac™ AS11-HC column with KOH gradient elution, with retention times of 13.67 min and 14.88 min, respectively, eliminating interference from common anions. • • The method provides a limit of quantification (LOQ) of 0.005 mg·L−1 for N3− in solution, translating to minimum quantifiable air concentrations of 0.00256 mg·m−3 for hydrazoic acid and 0.00387 mg·m−3 for sodium azide, enabling detection below the occupational exposure limit. • • Spiked recoveries ranged from 92.0% to 100.4% across low (0.005 mg·L−1), medium (0.010 mg·L−1), and high (0.050 mg·L−1) levels, with relative standard deviations (RSD, n=6) between 0.76% and 2.51%, demonstrating high accuracy and precision. • • The method uses a simple sampling approach: 40 mg·L−1 KOH as absorption solution for vapor/mist and microporous membrane for sol, followed by elution, making it practical for routine workplace air monitoring.