A novel automatic stepwise injection headspace single-drop micro-extraction system is proposed as a versatile approach for automated determination of volatile compounds. The system application is demonstrated for ammonia determination in concrete samples. An ammonia gas was produced from ammonium ions and extracted on-line into 5 μL 0.1 M H3PO4 to eliminate the interference effect of concrete species on the ammonia stepwise injection spectrophotometric determination. The linear range was 0.1 to 1 mg kg−1 with LOD 30 µg kg−1. The sample throughput was 4 h−1. This system has been successfully applied for the determination of ammonia in concretes..
Timofeeva, I., Khubaibullin, I., Kamencev, M., Moskvin, A., & Bulatov, A. (2015). Automated procedure for determination of ammonia in concrete with headspace single-drop micro-extraction by stepwise injection spectrophotometric analysis. Talanta, 133, 34-37. https://doi.org/10.1016/j.talanta.2014.04.081