Gerald Bauer

Recent advances in quantitative LA-ICP-MS analysis: challenges and solutions in the life sciences and environmental chemistry

Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) is a widely accepted method for direct sampling of solid materials for trace elemental analysis. The number of reported applications is high and the application range is broad; besides geochemistry, LA-ICP-MS is mostly used in environmental chemistry and the life sciences. This review focuses on the application of LA-ICP-MS for quantification of trace elements in environmental, biological, and medical samples. The fundamental problems of LA-ICP-MS, such as sample-dependent ablation behavior and elemental fractionation, can be even more pronounced in environmental and life science applications as a result of the large variety of sample types and conditions. Besides variations in composition, the range of available sample states is highly diverse, including powders (e.g., soil samples, fly ash), hard tissues (e.g., bones, teeth), soft tissues (e.g., plants, tissue thin-cuts), or liquid samples (e.g., whole blood). Within this article, quantification approaches that have been proposed in the past are critically discussed and compared regarding the results obtained in the applications described. Although a large variety of sample types is discussed within this article, the quantification approaches used are similar for many analytical questions and have only been adapted to the specific questions. Nevertheless, none of them has proven to be a universally applicable method.

Recent developments of iron pincer complexes for catalytic applications

Iron catalysis is attractive for organic synthesis because iron is inexpensive, abundant, and non-toxic. To control the activity and stability of an iron center, a large number of iron pincer complexes have been synthesized. Many such complexes exhibit excellent catalytic activity in a number of important organic reactions such as hydrogenation, hydrosilylation, dehydrogenation, and carbon–carbon bond forming reactions. In this review, recent examples of representative iron pincer catalysts are presented.

Dispersed particle extraction--a new procedure for trace element enrichment from natural aqueous samples with subsequent ICP-OES analysis.

A novel sample pre-treatment method for multi trace element enrichment from environmental waters prior to optical emission spectrometry analysis with inductively coupled plasma (ICP-OES) is proposed, based on dispersed particle extraction (DPE). This method is based on the use of silica nanoparticles functionalized with strong cation exchange ligands. After separation from the investigated sample solution, the nanoparticles used for the extraction are directly introduced in the ICP for measurement of the adsorbed target analytes. A prerequisite for the successful application of the developed slurry approach is the use of sorbent particles with a mean size of 500 nm instead of commercially available μm sized beads. The proposed method offers the known advantages of common bead-injection (BI) techniques, and further circumvents the elution step required in conventional solid phase extraction procedures. With the use of 14.4 mL sample and addition of ammonium acetate buffer and particle slurry limits of detection (LODs) from 0.03 μg L(-1) for Be to 0.48 μg L(-1) for Fe, with relative standard deviations ranging from 1.7% for Fe and 5.5% for Cr and an average enrichment factor of 10.4 could be achieved. By implementing this method the possibility to access sorbent materials with irreversible bonding mechanisms for sample pre-treatment is established, thus improvements in the selectivity of sample pre-treatment procedures can be achieved. The presented procedure was tested for accuracy with NIST standard reference material 1643e (fresh water) and was applied to drinking water samples from the vicinity of Vienna.

A Novel Nickel Pincer Complex in the Active Site of Lactate Racemase

Put through the pincer: A recent study revealed the structure of the Ni-containing active site of lactate racemase. The Ni is coordinated by a SCS pincer ligand derived from a nicotinic acid mononucleotide.

Sol–gel films with polymodal porosity by surfactant-assisted breath figure templating

The combination of breath figure templating to produce macro pores and surfactant self-assembly to induce micro-phase separation at the nanometre length scale are demonstrated for obtaining macro-mesoporous silica or mixed-oxide films. Control of the humidity or temperature was not necessary, and simple coating techniques can be applied.