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BACKGROUND The contents of silver, tin, boron, molybdenum, and lead in geological samples are extremely important for studying the metallogenic regularity and for geochemical prospecting. Current analytical methods rarely determine silver, tin, boron, molybdenum, and lead simultaneously. OBJECTIVES To establish a method to simultaneously determine silver, tin, boron, molybdenum and lead in geological samples. METHODS To eliminate the matrix interference, first-class standard materials (rock, soil and water sediments) were used for linear fitting of the synthetic silicate standard materials curve. By setting analytical line conversion values, different analytical line can be used for samples with different contents. RESULTS The detection limits of silver, tin, boron, molybdenum, and lead were 0.0077μg/g, 0.19μg/g, 0.68μg/g, 0.058μg/g, 0.49μg/g, respectively. The precisions of the method were 3.23%-9.39%. The measured value of national first class standard materials including soil, water sediments and rock by this method was in accordance with standard values, with an absolute value of △logC < 0.10. The qualified rates of actual sample were 92%-98%, and the qualified rate of the inspection sample was 100%. CONCLUSIONS This method is easy to apply and can be used to analyze samples rapidly. It can also be used to avoid contamination during sample dilution. Compared with traditional atomic emission spectrometry that uses a single analytical spectrum line, this method can be used to obtain a value which is closer to the standard value of national standard materials. The detection limit of this method is much lower than the standard value of the specification of testing quality management for geological laboratories.

Many studies in metal‐organic frameworks (MOFs) aiming for high photocatalytic activity resort to self‐assembling both energy donor and acceptor building units in skeleton to achieve effective energy transfer, which, however, usually needs tedious synthetic procedure and design of a new MOF. In this work, we demonstrated that building a Förster resonance energy transfer (FRET) pathway can be realized through suitable molecular doping in a given MOF structure without altering the original porous structure, presenting an alternative strategy to design efficient photocatalysts for CO2 reduction. In situ electron spin resonance, ultrafast transient absorption spectroscopy, and computational studies reveal that the FRET‐induced excitation has dramatically altered the exciton transfer pathway in structure and facilitated electron‐hole separation. As a result, the molecular doped MOFs synthesized through one‐pot reaction show outstanding selectivity (96%) and activity (1314 μmol·g−1·h−1) for CO production versus almost no activity for the pristine MOFs, and this result stands out from existing competitors. Furthermore, the reaction mechanism was proposed and the intermediate signals were detected by in situ diffuse reflectance infrared Fourier transform spectroscopies. This study presents a clear picture of building FRET process in MOFs through molecular doping and provides a new design strategy for MOF‐based photocatalysts. [ABSTRACT FROM AUTHOR]

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