Quantification of Microplastics in environmental samples using pressurized liquid extraction and Pyr-GC/MS

<p>Fast and reliable quantification of microplastics in environmental samples is currently a challenging task. To enable monitoring of microplastics, a fast and robust method in sample preparation and subsequent analysis is of extraordinary need and urgency. Therefore, the combination of pressurized liquid extraction and Pyr-GC/MS has been developed. The fully automated extraction includes a pre-extraction via methanol for matrix elimination and a subsequent main extraction for microplastics using tetrahydrofuran to enrich microplastics on silica gel which is hence analyzed by means of Pyr-GC/MS.</p><p>Several commonly occurring organic matrices known to result in GC interferences were tested to be eliminated by pressurized liquid extraction.  For the most frequently used synthetic polymers PE, PP, and PS extraction efficiencies of 113-131, 80-98, and 70-118 %, respectively, and limits of quantification down to 0.005 mg/g were achieved.</p><p>The developed method was validated and applied to environmental samples with complex matrices such as roadside soils, potting soils, and sewage sludge. In all these matrices PE, PP, and PS were detected with contents ranging from 0.8 to 3.3, 0.01 to 0.36, and 0.06 to 0.61 mg/g. However, calcined sea sand spiked with wood, leaves, and humic acids, respectively, were found to interfere with PE quantification (0.140, 0.210, and 0.050 mg/g). Reduction of these interferences will be further evaluated.</p>

Analysis of Ammonium in Seawater by Ion Chromatography With Single-Pump Column Switching

An ion chromatograph single-pump column-switching system was developed for the determination of ammonium in high salt matrices. The simple system included a pump, a suppressor, two valves, two columns, a single eluent, and a conductivity detector. Using this method, both online collection and matrix elimination were achieved. Ammonium was eluted from the acceptor loop to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r = 0.9997) in the range of 0.05‐2.0 mg/L and satisfactory repeatability (RSD < 4%, n = 6). The limit of detection was 4 μg/L (S/N = 3) with 25 μl injection. The utilization of the method was demonstrated by the analysis of seawater, with satisfactory spiked recoveries of ammonium between 98.8% and 108.7%. The result showed that the single-pump column-switching system was convenient and practical for the determination of low-level ammonium in high-salinity samples.

Polymer based sorbent materials for thermal ionization mass spectrometric determination of uranium(vi) and plutonium(iv) ions

Polymeric material based sorbents have been developed for the single step matrix elimination and source preparation for TIMS analyses of U(vi) and Pu(iv) ions, preconcentrated from a variety of environmental and nuclear fuel reprocessing samples.