Determination of trace copper by solid substrate-room temperature phosphorescence quenching method based on activating effect of α,α′-dipyridyl on Vitamin C reducing beryllon

A new solid substrate-room temperature phosphorescence quenching method for the determination of trace copper has been established. It is based on the fact that beryllon (R) can emit strong and stable solid substrate-room temperature phosphorescence on the filter paper, and Vitamin C (Vc) reduces R to non-phosphorescent compound that leads to solid substrate-room temperature phosphorescence (SS-RTP) quenching of R, and α,α′-dipyridyl can activate copper catalyzing Vitamin C reducing R. The ΔIp of the system with α,α′-dipyridyl is 3.3 times higher than that without α,α′-dipyridyl, which shows the reaction of α,α′-dipyridyl activating copper catalyzing Vitamin C reducing R. The reducing value of phosphorescence intensity (ΔIp) is directly proportional to the content of Cu(II) in the range of 0.040–4.0 fg spot−1 (corresponding concentration: 0.10–10.0 pg ml−1, sample volume: 0.40 μl spot−1). The regression equation of working curve can be expressed as ΔIp = 69.99 + 41.00 m Cu2+ (fg spot−1) (r = 0.9980, n = 6), and the detection limit is 0.0088 fg spot−1(corresponding concentration: 2.2 × 10−14 g ml−1). This sensitive and accurate method with good repeatability and high selectivity has been applied to the determination of trace copper in real samples with satisfactory results. The reaction mechanism for the determination of trace copper by solid substrate-room temperature phosphorescence quenching method based on the activating effect of α,α′-dipyridyl on Vitamin C reducing beryllon is also discussed.