High-Sensitivity and High-Performance Determination of Trace Aluminum in Water for Pharmaceutical Purposes by Microwave Plasma and Inductively Coupled Plasma–Atomic Emission Spectrometry

Procedures for the determination of aluminum in water for injections (Aqua ad iniectabilia) and high-purity water (Aqua valde purificata) at a level of several µg?L^?1 using atomic-emission spectrometry with a novel microwave plasma (MP–AES) and inductively coupled plasma (ICP–AES) are proposed. Regardless of the atomic-emission technique used, the procedure for aluminum needs no sample preparation (acidification only), no preconcentration, shows high sensitivity (limits of detection of 0.4 and 0.7?µg?L^?1 for ICP–AES and MP–AES with a polymeric inert concentric nebulizer, respectively, and 0.03?µg?L^?1 for ICP–AES with an ultrasonic nebulizer), high precision (repeatability, relative standard deviation, <5%), and high throughput (25 samples per hour), and is considerably simpler and more expedient from the viewpoint of the analysis cost and time compared with the standard spectrofluorimetric procedure of the US and the European Pharmacopoeia.