Accelerated hydrazone formation in charged microdroplets.

RATIONALE: Electrospray ionization-mass spectrometry (ESI-MS) is an emerging tool for reaction monitoring. It can be accompanied by reaction acceleration in charged droplets. METHODS: The time course of the bulk reaction of indoline-2,3-dione with phenylhydrazine in methanol to produce 3-(2- phenylhydrazono)indolin-2-one was monitored by ESI. Both nanoESI and electrosonic spray ionization (ESSI) were used for this study as representing two common forms of ionization for reaction monitoring. The effect on product yield of the distance the droplets travel between the source and the MS inlet was varied and product/starting material ratios were examined. RESULTS: Product yield is dramatically increased by increasing the distance. At short distances reaction monitoring can be performed without acceleration and at greater distances reaction acceleration occurs. This distance effect over the course of the reaction roughly parallels the time dependence of the bulk-phase reaction. CONCLUSIONS: Reaction acceleration in droplets is attributed to solvent evaporation leading to increased surface to volume ratios. An acceleration factor of 10(4) , measured relative to the bulk reaction at short times, is readily achieved by simply increasing the droplet distance of flight showing that the same ionization source can be used to monitor reactions with or without acceleration. Copyright © 2016 John Wiley & Sons, Ltd.

Characterizing college science instruction: The Three-Dimensional Learning Observation Protocol.

The importance of improving STEM education is of perennial interest, and to this end, the education community needs ways to characterize transformation efforts. Three-dimensional learning (3DL) is one such approach to transformation, in which core ideas of the discipline, scientific practices, and crosscutting concepts are combined to support student development of disciplinary expertise. We have previously reported on an approach to the characterization of assessments, the Three-Dimensional Learning Assessment Protocol (3D-LAP), that can be used to identify whether assessments have the potential to engage students in 3DL. Here we present the development of a companion, the Three-Dimensional Learning Observation Protocol (3D-LOP), an observation protocol that can reliably distinguish between instruction that has potential for engagement with 3DL and instruction that does not. The 3D-LOP goes beyond other observation protocols, because it is intended not only to characterize the pedagogical approaches being used in the instructional environment, but also to identify whether students are being asked to engage with scientific practices, core ideas, and crosscutting concepts. We demonstrate herein that the 3D-LOP can be used reliably to code for the presence of 3DL; further, we present data that show the utility of the 3D-LOP in differentiating between instruction that has the potential to promote 3DL from instruction that does not. Our team plans to continue using this protocol to evaluate outcomes of instructional transformation projects. We also propose that the 3D-LOP can be used to support practitioners in developing curricular materials and selecting instructional strategies to promote engagement in three-dimensional instruction.