Abstract
We report on a novel gel based on diffusive gradients in thin films (DGT) for the simultaneous measurement of cations and anions and its suitability for high resolution chemical imaging by using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). The new high resolution mixed binding gel (HR-MBG) is based on zirconium-hydroxide and suspended particulate reagent-iminodiacetate (SPR-IDA) as resin materials which are embedded in an ether-based urethane polymer hydrogel. The use of this polymer hydrogel material allows the production of ultrathin, highly stable and tear-proof resin gel layers with superior handling properties compared to existing ultrathin polyacrylamide gels. The gel was characterized regarding its uptake kinetics, the anion and cation capacities, and the effects of pH, ionic strength, and aging on the performance of the HR-MBG. Our results demonstrate the capability of this novel gel for concomitant sampling of anions and cations. The suitability of this new gel type for DGT chemical imaging at submm spatial resolution in soils using LA-ICPMS is shown. 2D images of P, As, Co, Cu, Mn, and Zn distributions around roots of Zea mays L. demonstrate the new opportunities offered by the HR-MBG for high-resolution mapping of solute dynamics in soil and sediment hotspots, such as the rhizosphere, by simultaneous observation of anionic and cationic solute species.
Highlights
Diffusive gradients in thin films (DGT) is a passive sampling technique widely used for measuring solutes in water, sediments, and soils.[6−10] In many cases, the DGT-labile solute fraction correlated better with the plant uptake than that measured by chemical extractants.[3,10] A recent isotope dilution study directly demonstrated that the DGT-labile soil P fraction is largely identical to the plant-available fraction, whereas a range of chemical extractants either under- or overestimated plant-available P.4
Ultrathin gels allow for the application of a second layer of a planar sensor at the back of the resin gel, for example, a second DGT gel or a planar optode.[32]
We developed a novel DGT resin gel, the high resolution mixed binding gel (HR-MBG), which facilitates the simultaneous high-resolution LA-ICPMS imaging of anionic and cationic solutes
Summary
Article spatial resolution along the scan line and a significant reduction in measurement time. Standards for LA-ICPMS were prepared by deploying HRMBG gels in DGT samplers in 3 L of deployment solution at varying analyte concentrations and deployment times. Natural soils, solute concentrations of the analytes targeted by this resin gel are often in the range of 0.1−500 μg L−1.37 In such environments, interactive effects as seen in this experiment should not occur. The difference of the cDGT values and the directly measured concentrations, as well as the standard deviation of the cDGT concentrations, increased considerably (Figure 3) These results suggest that the HR-MBG should be used within 47 days after production to obtain an optimal DGT response for all tested analytes. The blank levels of P and Cd with 130 and Article
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
