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Affinity analysis is a key biotechnique used in the fields of biology and biomedicine. Herein, we advanced the concept of moving affinity boundary (MAB) using metal ion Ni(II) and histidine (His) as the model inorganic ion and ligand, respectively, developed the simple method of MAB affinity capillary electrophoresis (MAB-ACE), and carried out the relative experiments. The experiments manifested that (a) an MAB could be created with the model metal ion and ligand; (b) the MAB-ACE could specifically capture His rather than other amino acids, or numerous metabolites in human urine; and (c) the capture had the merits of simultaneous focusing and separation to the target metabolite of His. It was further revealed that the specificity of MAB-ACE was originated from the selective affinity interaction and the effective control of affinity conditions. The analyses of His in raw urine by the MAB-ACE are in agreement with those via the standard amino acid analyzer, indicating the reliability of the developed method. Additionally, the MAB-ACE with UV detector had good sensitivity (LOD = 43 ng mL(-1), S/N = 3), 1.0-150 microM linearity and <5% intra-/inter-day variations. The novel method has an evident potential application for capture of a target metabolite in complex biological sample.

Gallium−indium eutectic (eGaIn) is a liquid metal being explored in a number of applications because of its high thermal/electrical conductivity and favorable deformability. A key function regulating the mechanical properties of eGaIn is the ability to rapidly form a passivating oxide layer, which is known to occur upon exposure to air under ambient conditions. Nevertheless, little is known about the molecular level surface reactivity of eGaIn toward oxygen and water vapor under in situ conditions. Herein we present ambient pressure X-ray photoelectron spectroscopy results examining the liquid− gas interface of eGaIn in the presence of oxygen and water vapor. By examining each gas independently, results reveal that both oxygen and water vapor react with Ga in eGaIn to form the same oxidized products: Ga 3+ oxide (Ga 2 O 3 ) as an outer layer and Ga 1+ oxide (Ga 2 O) as an interlayer. Despite similar product formation, stark differences are observed in pressure-dependence and adsorbate-induced binding energy shifts. The results herein suggest both oxygen and water vapor uniquely contribute to the oxidative passivation of eGaIn under ambient conditions.

Recent advances in manipulating plasmonic properties of metal/semiconductor heterostructures have opened up new avenues for basic research and applications. Herein, we present a versatile strategy for the assembly of arrays...