We report the application of three-dimensional positron emission tomography/computed tomography (PET/CT) for the analysis of (13)NO(3)(-) uptake and (13)N distribution in growing kohlrabi. The analytical procedures, equipment parameters, and image reconstruction mode for plant imaging were tested and selected. (13)N in growing kohlrabi plants was imaged versus time using both PET movies and PET/CT tomograms. The (13)NO(3)(-) transport velocity in kohlrabi from root to petiole was estimated to be 1.0 cm/min. The appearance of shell-shaped (13)NO(3)(-) transport pathways, corresponding to the kohlrabi corm, suggests the existence of special routes with higher efficiency for (13)NO(3)(-) transport, which tends to have the shortest distances to the leaves or buds. Standardized uptake values (SUVs), used as the representative figures for describing (13)N distribution, were quantified versus time at some putative sites of interest. For multiple analysis of the same-plant, (13)N distribution in kohlrabi under normal conditions, methionine sulfoximine (MSX) stress, and recovery from MSX stress was examined. The (13)N distribution variation studies were also done under the above three growth conditions. Our results suggest a significant downregulation of nitrate uptake in kohlrabi in the presence of MSX.

A flow method of high-performance liquid chromatography (HPLC) seperation and chemiluminescence (CL) detection for sensitive vardenafil analysis in dietary supplements was developed. The vardenafil separation was achieved on a C18 column at 30°C using ethanol-H3PO4 and ethylenediaminetetraacetic acid disodium salt (Na2EDTA) aqueous solution (25 : 75, v/v%) as mobile phase. The followed continuous CL detection was conducted based on the strong CL enhancement by the presence of vardenafil to luminol-K3Fe(CN)6 reaction in alkaline medium. At the flow rate of 0.8 mL/min, the vardenafil retention time (tR) was 6.4 min. Factors that affected the HPLC resolution and CL detection were studied and optimized. The calibration curve obtained for vardenafil standard was linear in concentration range of 8.0 × 10−7 ~ 1.0 × 10−4 mol/L. The relative standard deviations (RSD) of intraday and interday precision were less than 3.5%. The proposed method was applied to the vardenafil determination in oral liquid, wine, and capsule samples.

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Sonoluminescence can photoexcite fluorescent solutes yielding sonophotoluminescence (SPL). The possibility of applying multibubble sonophotoluminescence (MBSPL) for chemical quantitative analysis is examined in this work. Special devices for MBSPL quantitative detection are designed and fabricated. Calcium contents in pharmaceutical samples are selected to verify the proposed MBSPL analysis. Coupled with flow fluid manifold, high detection frequency, good reproducibility and automatic operation are obtained. Further applications of presented method to detecting a variety of chemical or biochemical molecules in low quantities are expected.