Si-based solar cells have dominated the entire photovoltaic market, but remain suffering from low power conversion efficiency (PCE), partly because of the poor utilization of ultraviolet (UV) light. Europium(III) (Eu 3+) complexes with organic ligands are capable of converting UV light into strong visible light, which makes them ideal light converter to increase the efficiency of solar cells. However, the low stability of such complexes seriously hampers their practical applications. In this work, we report a highly stable and luminescent ethylene-vinyl acetate (EVA) copolymer film consisting of a Eu 3+ complex as a down-shift material, Eu (ND) 4 CTAC (ND = 4-hydroxy-2-methyl-1,5-naphthyridine-3carbonitrile, CTAC = hexadecyl trimethyl ammonium chloride), coating of which onto the surface of large area polycrystalline silicon solar cells (active area: 110 cm 2) results in an increase of PCE from 15.06% to 15.57%. Remarkable stability of the luminescent film was also demonstrated under lightsoaking test for 500 h, and no obvious luminescence degradation can be observed. The remarkable enhancement of the conversion efficiency by 0.51% absolute on such a large active area, together with the high stability of the luminescent film, demonstrates a prospect for the implementation of the films in photovoltaic industry.

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Determination of amino acids in biofluids is a challenging task because of difficulties deriving from their high polarity and matrix interference. A simple, reliable and highthroughput hydrophilic interaction UHPLC-MS/MS method was developed and validated for the rapid simultaneous determination of 19 free amino acids in rat plasma and urine samples in this paper. Hydrophilic method with a Waters Acquity UPLC BEH Amide column (100 × 2.1 mm,1.7 μm) was used with a gradient mobile phase system of acetonitrile and water both containing 0.2% formic acid. The analysis was performed on a positive electrospray ionization mass spectrometer via multiple reaction monitoring. Samples of 10 μL plasma and 50 μL urine were spiked with three deuterated internal standards, pretreated with 250 μL acetonitrile for one-step protein precipitation and a final dilution of urine samples. Good linearities (r > 0.99) were obtained for all of the analytes with the lower limit of quantification from 0.1 to 1.2 μg/mL. The relative standard deviation of the intra-day and inter-day precisions were within 15.0% and the accuracy ranged from −12.8 to 12.7%. The hydrophilic interaction UHPLC-MS/MS method was rapid, accurate and high-throughput and exhibited better chromatography behaviors than the regular RPLC methods. It was further successfully applied to detect 19 free amino acids in biological matrix. KEYWORDS19 free amino acids, determination, hydrophilic interaction ultra-high-performance liquid chromatography-tandem mass spectrometry, rat plasma, urine

In this paper, an ultra high performance liquid chromatography tandem mass spectrometric (UPLC-ESI-MS/MS) method in positive ion mode was established to systematically identify and to compare the major aconitum alkaloids and their metabolites in rat plasma and urine after oral administration of Fuzi extract. A total twenty-nine components including twenty-five C19-diterpenoid alkaloids and four C20-diterpenoid alkaloids were identified in Fuzi extract. Thirteen of the parent components and five metabolites were detected in rat plasma and sixteen parent compounds and six metabolites in urine. These parent components found in rat plasma and urine were mainly C19-diterpenoid alkaloids. All of the metabolites in vivo were demethylated metabolites (phase I metabolites), which suggested that demethylation was the major metabolic pathway of aconitum alkaloids in vivo. A comparison of the parent components in rat plasma and urine revealed that 3-deoxyacontine was found in plasma but not in urine, while kalacolidine, senbusine and 16-β-hydroxycardiopetaline existed in urine but not in plasma, which indicated that most alkaloids components were disposed and excreted in prototype form. This research provides some important information for further metabolic investigations of Fuzi in vivo.

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