Comparison of non-protected fluid room temperature phosphorescence properties of α-naphthyloxyacetic acid and β-naphthyloxyacetic acid Original Research Article

In this paper, the non-protected room temperature phosphorescence (NP-RTP) properties of α-naphthyloxyacetic (α-NOA) and β-naphthyloxyacetic acid (β-NOA) and effects of organic solvents have been studied to clarify the effects of position of substituent on the luminescence. Both α-NOA and β-NOA aqueous solutions can emit strong and stable RTP signal in the absence of a protecting medium by addition of KI or TlNO3 as heavy atom perturber (HAP) and Na2SO3 as deoxygenator. The fluid RTP system is completely transparent and stable. A good linearity between the RTP intensity and the concentration was obtained with detection limits of 1.0×10−8 and 1.2×10−8 mol/l, respectively, for α-NOA and β-NOA. The kind 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 TlNO3 as HAP is much stronger than that of the system using KI as HAP, but the detection limits of both systems for analytical determination are comparable. The RTP intensity of β-NOA is lower than that of α-NOA, but the influence of organic solvent on its RTP emission is also less. Determination of α-NOA in spiked pond water using standard additions method was performed, the recoveries are 97–102%.