CHEM 2AA3 Lecture Notes - Lecture 2: Bathochromic Shift, Ionophore, Redshift
27 Sep 2016
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Thoron form s a weak complex with lithium in alkaline acetone/water solutions which results in a bathochromic shift (red shift) of its spectrum. 1-8 dihydroxyanthraquinone as fluorescence agent to li in deproteinized serum, exhibit 480:1 selectivity over sodium. Ion selective electrodes: electrochemical method: change in potential/voltage. 14-crown-4-ethers have proved to be excellent ionophores for li ises, particularly when containing bulky groups to prevent formation of 2:1 sodium complex. Crown ethers are tethered to an electrode and li activity is measured via potentiometry. Can be used directly in diluted serum after removal of rbc. Elute using mobile phase of water, methanol and acid (ensure no anionic computer around and for ms) Use c-18 coated silica particles as stationary phase. Caffeine will stick to stationary phase more strongly than theobromine. Detect analyte at column by absorbance at 254 nm. Need to use ms or spiking with known sample to identify which peak is which.
