Editing Digital microfluidics (section)

===Nuclear magnetic resonance spectroscopy===

[[Nuclear magnetic resonance spectroscopy|Nuclear magnetic resonance (NMR) spectroscopy]] can be used in conjunction with digital microfluidics (DMF) through the use of NMR microcoils, which are electromagnetic conducting coils that are less than 1&nbsp;mm in size. Due to their size, these microcoils have several limitations, directly influencing the sensitivity of the machinery they operate within.

Microchannel/microcoil interfaces, previous to digital microfluidics, had several drawbacks such as  in that many created large amounts of solvent waste and were easily contaminated.<ref name="Swyer">{{cite journal | vauthors = Swyer I, Soong R, Dryden MD, Fey M, Maas WE, Simpson A, Wheeler AR | title = Interfacing digital microfluidics with high-field nuclear magnetic resonance spectroscopy | journal = Lab on a Chip | volume = 16 | issue = 22 | pages = 4424–4435 | date = November 2016 | pmid = 27757467 | doi = 10.1039/c6lc01073c }}</ref><ref name="Lei_2015">{{cite journal | vauthors = Lei KM, Mak PI, Law MK, Martins RP | title = A palm-size μNMR relaxometer using a digital microfluidic device and a semiconductor transceiver for chemical/biological diagnosis | journal = The Analyst | volume = 140 | issue = 15 | pages = 5129–37 | date = August 2015 | pmid = 26034784 | doi = 10.1039/c5an00500k | bibcode = 2015Ana...140.5129L | doi-access = free }}</ref> In this way, the use of digital microfluidics and its capability to manipulate singlet droplets is promising.

The interface between digital microfluidics and NMR [[relaxometry]] has led to the creation of systems such as those used to detect and quantify the concentrations of specific molecules on microscales<ref name="Lei_2015" /> with some such systems using two step processes in which DMF devices guide droplets to the NMR detection site.<ref>{{cite journal | vauthors = Lei KM, Mak PI, Law MK, Martins RP | title = NMR-DMF: a modular nuclear magnetic resonance-digital microfluidics system for biological assays | journal = The Analyst | volume = 139 | issue = 23 | pages = 6204–13 | date = December 2014 | pmid = 25315808 | doi = 10.1039/c4an01285b | bibcode = 2014Ana...139.6204L | doi-access = free }}</ref> Introductory systems of high-field NMR and 2D NMR in conjunction with microfluidics have also been developed.<ref name="Swyer" />  These systems use single plate DMF devices with NMR microcoils in place of the second plate. Recently, further modified version of this interface included pulsed field gradients (PFG) units that enabled this platform to perform more sophisticated NMR measurements (e.g. NMR diffusometry, gradients encoded pulse measurements).<ref name="Swyer_2019">{{cite journal | vauthors = Swyer I, von der Ecken S, Wu B, Jenne A, Soong R, Vincent F, Schmidig D, Frei T, Busse F, Stronks HJ, Simpson AJ, Wheeler AR | title = Digital microfluidics and nuclear magnetic resonance spectroscopy for in situ diffusion measurements and reaction monitoring | journal = Lab on a Chip | volume = 19 | issue = 4 | pages = 641–653 | date = January 2019 | pmid = 30648175 | doi = 10.1039/C8LC01214H | s2cid = 58600090 }}</ref> This system has been successfully applied into monitoring rapid organic reactions.<ref name="Wu_2019">{{cite journal | vauthors = Wu B, von der Ecken S, Swyer I, Li CL, Jenne A, Vincent F, Schmidig D, Kuehn T, Beck A, Busse F, Stronks HJ, Soong R, Wheeler AR, Simpson AJ | title = Rapid Chemical Reaction Monitoring by Digital Microfluidics-NMR: Proof of Principle Towards an Automated Synthetic Discovery Platform | journal = Angewandte Chemie International Edition | volume = 58 | issue = 43 | pages = 15372–15376 | date = October 2019 | pmid = 31449724 | doi = 10.1002/anie.201910052 | s2cid = 201728604 }}</ref>