Comparison of non-protected fluid room temperature phosphorescence properties of alpha-naphthyloxyacetic acid and beta-naphthyloxyacetic acid

In this paper, the non-protected room temperature phosphorescence (NP-RTP) properties of alpha -naphthyloxyacetic (alpha -NOA) and beta -naphthyloxyac etic acid (beta -NOA) and effects of organic solvents have been studied to clarify the effects of position of substituent on the luminescence. Both al pha -NOA and beta -NOA aqueous solutions can emit strong and stable RTP sig nal in the absence of a protecting medium by addition of KI or TINO3 as hea vy atom perturber (HAP) and Na2SO3 as deoxygenator. The fluid RTP system is completely transparent and stable. A good linearity between the RTP intens ity and the concentration was obtained with detection limits of 1.0 x 10(-8 ) and 1.2 x 10(-8) mol/l, respectively, for alpha -NOA and beta -NOA. The k ind and amount of organic solvent added to the luminescent system not only affect the RTP intensity and the pre-irradiation time required to attain a stable RTP signal, but also the selection of HAP. Under the same conditions , the RTP intensity of the system using TINO3 as HAP is much stronger than that of the system using KI as HAP, but the detection limits of both system s for analytical determination are comparable. The RTP intensity of beta -N OA is lower than that of alpha -NOA, but the influence of organic solvent o n its RTP emission is also less. Determination of alpha -NOA in spiked pond water using standard additions method was performed, the recoveries are 97 -102%. (C) 2000 Elsevier Science B.V. All rights reserved.