Preparation and Photocatalytic Application of the Composites PMo12/AgNPs Based on Polyoxometalates.

Supported catalysts, consisting of PMo12 immobilized on silver nanomaterials at different recombination time and the silver nanomaterials with different template sodium citrate amount characterized by FT-IR, XRD, SEM, UV-vis and other test methods. The results show that the AgNPs are relatively uniformed with sizes between 100-300 nm when the sodium citrate addition amount is 9.0 mL. As the reaction time of PMo12/AgNPs increases, the adhesion of AgNPs on the surface of PMo12 becomes more complete. Using PMo12 and PMo12/AgNPs composite materials as catalysts, methylene blue (MB) is photocatalytically degraded under simulated visible light conditions. The results show that PMo12 can catalyze MB effectively, and the decolorization rate reached 98.6% when the catalyst content is 2 g/L, the solution pH is 3 and the MB concentration is 5 mg/L. Under the same experimental conditions, photocatalytic performance of the PMo12/AgNPs system is better than that of the PMo12 further improved the photocatalytic degradation effect of the MB solution with a decolorization rate of 100%. The composite still keeps good photocatalytic activity and stability after three cycles of use. Finally, the catalytic mechanism of the POMs composite material is preliminarily discussed.

Development and validation of a universal primer pair for the simultaneous detection of eight animal species.

In the present study, we developed a novel simplex PCR assay for the simultaneous detection of eight animal species, including goat, sheep, deer, buffalo, cattle, yak, pig and camel. A unique pair of universal primers was designed to target mitochondrial DNA variable regions in the eight animal species, generating, 787, 763, 563, 512, 507, 491, 455 and 385bp long fragments for goat, sheep, deer, buffalo, cattle, yak, pig and camel, respectively. The assay showed no cross-reactivity with other common domestic animals, and was validated by sequencing and enzyme digestion. Detection limit for DNA samples from the eight animal species varied between 6 and 20pg in a 20µl PCR mixture. Interestingly, the newly developed method successfully identified 170 commercial meat products, and is simple, fast, sensitive, specific, and cost-effective. Therefore, it could be used for the detection of goat, sheep, deer, buffalo, cattle, yak, pig, and camel species in foodstuffs.

[Determination of volatile N-nitrosamine compounds in salted aquatic products by gas chromatography-mass spectrometry].

An analytical method was developed for the determination of the extraction of volatile N-nitrosamine compounds including N-nitrosodimethylamine ( NDMA) , N-nitrosodiethylamine (NDEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) from salted aquatic products by gas chromatography-mass spectrometry (GC-MS). In this experiment, the separation and detection conditions were optimized for different extraction methods, solid-phase extraction columns, and chromatographic columns. The results showed that the linear correlation coefficients (R2) were higher than 0. 999 8 within 10 - 1 000 micro g/L, and the reproducibilities were good with the - relative standard deviations (RSD) less than 8%. The recoveries were 79% - 105%. It is noted that this method for the determination of volatile N-nitrosamine compounds in salted aquatic products was much more sensitivity and with a lower detection limits (0. 05 micro g/kg except NDPA) than the previously reported methods. This proposed method is rapid and convenient for the determination, and easy for the operation. It is appropriate for the determination of volatile N-nitrosamine compounds in various salted aquatic products.