Determination of trace uranium by a photo-catalytic resonance fluorescence method coupled with dual cloud point extraction

(1) Extracting and purifying uranium in complex samples by dCPE with [UO22+–SA1]. (2) Detecting uranium super sensitively by a photocatalytic RF method with [UO22+–SA2]. (3) Coupling with separation, purification and analysis procedures exhibited a number of advantages, including high selectivity, high sensitivity and low cost.

298 K rate coefficients for the reaction of OH with <i>i</i> - C₃H₇I, <i>n</i> - C₃H₇I and C₃H₈

The kinetics of the title reactions were investigated using the laser photolysis - resonance fluorescence method, employing the sequential two-photon dissociation of NO2 in the presence of H2 as the OH source. The 298 K rate constant for OH + C3H8 was found to be (1.15 ± 0.1) × 10-12 cm3 s-1, in excellent agreement with the literature recommendation, and with a separate determination using HNO3 photolysis at 248 nm as the OH source. The 298 K rate constants for OH + n - C3H7I and i - C3H7I were measured for the first time and found to be (1.47 ± 0.08) and (1.22 ± 0.06) × 10-12 cm3 s-1, respectively. The errors include an assessment of systematic error due to concentration measurement, which, for the propyl-iodides was minimised by on-line UV-absorption spectroscopy. These results show that reaction with OH is an important sink for n - C3H7I and i - C3H7I, which has implications for the reactive iodine budget of the marine boundary layer.

298 K rate coefficients for the reaction of OH with i-C₃H₇I, n-C₃H₇I and C₃H₈

The kinetics of the title reactions were investigated using the laser photolysis - resonance fluorescence method, employing the sequential two-photon dissociation of NO2 in the presence of H2 as the OH source. The 298 K rate constant for OH + C3H8 was found to be (1.15±0.1) × 10-12 cm3 s-1, in excellent agreement with the literature recommendation, and with a separate determination using HNO3 photolysis at 248 nm as the OH source. The 298 K rate constants for OH + n-C3H7I and i-C3H7I were measured for the first time and found to be (1.47±0.08) and (1.22±0.06) × 10-12 cm3 s-1, respectively. The errors include an assessment of systematic error due to concentration measurement, which, for the propyl-iodides was minimised by on-line UV-absorption spectroscopy. The implications of these results for the reactive iodine budget of the marine boundary layer are discussed.