Sensitized near-infrared fluorescence from Yb（Ⅲ）-Calcein complex in methanol solution was studied.It was found that Calcein form 2∶1 complex with Yb（Ⅲ）in a pH 8.9 buffer solution.The visible fluorescence from Calcein was quenched when complex forms,while the near-infrared fluorescence from Yb（Ⅲ） was greatly sensitized.Near-infrared fluorescence of Yb（Ⅲ）was further enhanced when second ligand,such as tributyl phosphate（TBP）,1,10-Phenanthroline（phen）and trioctyl phosphine oxide（TOPO）,was added.It was also noted that the near-infrared fluorescence from Yb（Ⅲ）could also be enhanced by addition of small amount of Er3+ ions.
Glycine can react with acetylacetone and formaldehyde in HAc-NaAc buffer to give a product which can emit strong fluorescence.A Fluorometric determination of glycine in beverage was developed in the present work.The linear range was 0.1-200μg·mL-1.Experimental conditions such as pH of the solution,reaction temperature and reaction time were optimized.Effect of coexist compound was also discussed.The method can be applied to the determination of glycine in beverages.The recovery of the method is 91.8-107.5%.
