Multi-elemental analysis of particulate matter PM2.5 and PM10 by ICP OES

The complexity of aerodynamic particulate matter's (PM) matrices poses a challenge for the extraction and quantification of metals, especially for analytes with low concentration. Aiming to solve this issue, a precise and accurate protocol with the ultrasound extraction combined with microwave radiation digestion (USMW), was applied to PM samples with excellent compensations in sample throughput, digestion efficiency, and energy consumption. After the digestion and extraction procedures, the inorganic analytes, including rare earth elements, were determined by ICP OES. Two types of particulate matter sampled from two stations, Gobernacion (GOB10 and GOB2.5) and Milan (MIL10), corresponding to PM2.5 and PM10, were digested with a combination between HF, HNO3, and H3BO3. The absolute limits of detection ranged from 0.42 pg m-³ for V, to 3459 pg m-³ for As. The accuracy of the experimental study was assessed using two certified reference materials (CRMs), Coal Fly Ash (NIST1633b) and Fly Ash (BCR176). The method presented good accuracy, with recoveries ranging from 90 to 115%, except for Al (120%) and Fe (123%). Considering the replicates for the determination of analyte elements, the repeatability was below 10% for the relative standard deviation (RSD). A cloud point extraction (CPE) procedure, with parameters optimized for the determination of Pd and Pt, was successfully applied in digested PM samples with detection limits of 1.43 and 2.05 pg m−³ for Pd and Pt in MIL10 sample, respectively, and 76.6 pg m−³ for Pd and 110 pg m−³ for Pt, in samples GOB10 and GOB2.5, respectively. [Display omitted] •A new method for elemental quantification in PM2.5 and PM10 samples.•Ultrasound power combined with microwave assisted digestion for particulate sample preparation.•Cloud point extraction applied in digestion solution of PM samples prior to ICP OES multielement determination.•Rare earth elements determination in particulate matter by ICP OES.