Abstract: The present invention provides a GaN/two-dimensional AlN heterojunction rectifier on a silicon substrate and a preparation method therefor and belongs to the field of rectifiers. The rectifier comprises a silicon substrate, a GaN buffer layer, a carbon-doped semi-insulating GaN layer, a two-dimensional AlN layer, a non-doped GaN layer, a non-doped InGaN layer and a SiNx passivation layer that are stacked in sequence. The rectifier further comprises a mesa isolation groove and a Schottky contact electrode that are arranged at one side. The mesa isolation groove is in contact with the non-doped GaN layer, the non-doped InGaN layer, the SiNx passivation layer and the Schottky contact electrode. The Schottky contact electrode is in contact with the mesa isolation groove and the non-doped GaN layer. The thickness of the two-dimensional AlN layer is only several atomic layers, thus the received stress and polarization intensity are greater than those of the AlGaN layer.

Abstract: The invention is directed to the use of weak anion exchange (WAX) materials for trapping of negative and zwitterionic interferences from biological matrices, and then reduction of the biological matrix effect in the quantitative analysis process of basic and neutral compounds present in the matrix. The sample preparation process includes adding the WAX cleanup step before or after or during the conventional extraction procedures like liquid-liquid extraction, protein precipitation, solid phase extraction and others. Such a step greatly enhances the selectivity of the extraction process via the removal of the majority of the contaminants and reduces the matrix effect in the quantitative analysis. In addition, the WAX-enhanced extraction is very simple, versatile, rug and easy to be operated.

Abstract: The invention is directed to the use of weak anion exchange (WAX) materials for trapping of negative and zwitterionic interfaces from biological matrices, and then reduction of the biological matrix effect in the quantitative analysis process of basic and neutral compounds present in the matrix. The sample preparation process includes adding the WAX cleanup step before or after or during the conventional extraction procedures like liquid-liquid extraction, protein precipitation, solid phase extraction and others. Such a step greatly enhances the selectivity of the extraction process via the removal of the majority of the contaminants and reduces the matrix effect in the quantitative analysis. In addition, the WAX-enhanced extraction is very simple versatile, rug and easy to be operated.