New asymmetric tetradentate phenanthroline chelators with pyrazole and amide groups for complexation and solvent extraction of Ln(III)/Am(III).

To tune the complexation and solvent extraction performance of the ligands with a 1,10-phenanthroline core for trivalent actinides (An3+) and lanthanides (Ln3+), we synthesized two new asymmetric tetradentate ligands with pyrazole and amide groups, i.e., L1 (N,N-diethyl-9-(5-ethyl-1H-pyrazol-3-yl)-1,10-phenanthroline-2-carboxamide) and its analogue L2 with longer alkyl chains (N,N-dihexyl). The complexation of the ligands with Ln3+ was confirmed by 1H NMR titration and X-ray crystallography, and stability constants were measured in methanol by spectrophotometric titration. The asymmetric ligands exhibited an improved performance in terms of selective solvent extraction of Am3+ over Eu3+ in strongly acidic solutions compared to their symmetric analogues. The improved selectivity of the asymmetric ligands was interpreted theoretically by density functional theory simulations. This study implies that combining different functional groups to construct asymmetric ligands may be an efficient way to tune ligand performance with regard to An3+ separation from Ln3+.

Stable isotope labeling differential glycans discovery in the serum of acute myocardial infarction by ultrahigh-performance liquid chromatography-quadrupole-Orbitrap high resolution mass spectrometry.

Acute myocardial infarction (AMI) poses a grave threat to human life. However, most clinical biomarkers have limitations of low sensitivity and specificity. Therefore, screening novel glycan biomarkers with high sensitivity and specificity is crucial for the prevention and treatment of AMI. The novel method of ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) with d0/d5-BOTC probe labeling for relative quantification of glycans based on Pronase E digestion was established to screen novel glycan biomarkers in the serum of 34 AMI patients relative to healthy volunteers. The monosaccharide model D-glucosamine was used to investigate the effectiveness of the derivatization; the limit of detection (S/N = 3) was 10 amol. The accuracy was verified based on the consistency of different theoretical molar ratios (d0/d5 = 1:2, 2:1) and intensity ratios following digestion of glycoprotein ribonuclease B. Expressions of H4N4F3SA, H4N6F2, H4N6SA, H4N6F3 and H5N4FSA in the serum were significantly different (p < 0.0005) between AMI patients and healthy volunteers. The area under the receiver operating characteristic curve (AUC) for H4N6SA, H5N4FSA, and H4N6F2 was greater than 0.9039. Based on the proposed method, H4N6SA, H5N4FSA, and H4N6F2 in human serum showed high accuracy and specificity and may serve as potential glycan biomarkers, crucial for the diagnosis and treatment monitoring of AMI.