Solid substrate-room temperature phosphorimetry for the determination of trace terbutaline sulfate based on its inhibition oxidation of rhodamine 6G by sodium periodate

When 1.00 mol l(-1) I- is used as ion perturber, rhodamine 6G ( Rh 6G) can emit strong and stable room temperature phosphorescence (RTP) on filter paper substrate in KHC8H4O4-HCl buffer solution (pH=3.50), heated at 70 degrees C for 10 min. NaIO4 can oxidize Rh 6G, which makes the RTP signal quench. Terbutaline sulfate (TBS) can inhibit NaIO4 from oxidizing Rh 6G, which makes the RTP signal of Rh 6G enhance sharply. The content of TBS is linear correlation Delta Ip of the system. Based on the facts above, a new inhibition solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace TBS has been established. The linear range of this method is 0.0104-2.08 pg spot(-1) (corresponding concentration: 0.026-5.2 ng ml(-1), with a sample volume of 0.4 mu l) with a detection limit (L.D.) of 2.6 fg spot(-1) (corresponding concentration: 6.5 x 10(-12) g ml(-1)), and the regression equation of working curve is Delta Ip=2.040+54.54 m(TBS) (pg spot(-1)), n=6, correlation coefficient is 0.9994. For the samples containing 0.0104 pg spot(-1) and 2.08 pg spot(-1) TBS, the relative standard deviation (RSD) are 3.8% and 2.3% (n=8), respectively, indicating good precision. This method has been applied to determination of trace TBS in the practical samples with satisfactory results. The reaction mechanism of NaIO4 oxidizing Rh 6G to inhibit SS-RTP for the determination of trace TBS is also discussed.