Accurate quantification of structurally similar impurities in chiral drugs remains a critical challenge in pharmaceutical quality control. Herein, we established supercritical fluid chromatography-internal standard correction-solvent suppression-quantitative nuclear magnetic resonance (SFC-ISC-SS-qNMR) for the rapid and accurate purity assessment of low-purity quinine (QN). Baseline separation of QN from its chiral isomer quinidine was achieved within 10 min using SFC. The collected eluate, without any nitrogen blowing or freeze-drying, was directly mixed with an IS and a trace amount of deuterium oxide for 1H qNMR analysis, reducing the total sample preparation time to less than 7 min. An excitation sculpting pulse sequence (zgesgp) was employed to effectively suppress the methanol solvent peak, yielding a flat baseline and an excellent signal-to-noise ratio (S/N > 5000:1). Internal standard correction based on SFC peak area ratios before and after purification eliminated losses and errors during sample preparation. Method validation showed that the determined purity of QN (95.40% ± 0.17%) was in agreement with results obtained by two independent direct qNMR strategies (95.61% ± 0.11% and 95.44% ± 0.23%). Compared with previously reported ISC-high-performance liquid chromatography-qNMR and SFC-ISC-qNMR methods, the proposed approach significantly reduced the sample preparation time, completely avoided the nitrogen blowing or freeze-drying steps, and achieved seamless hyphenation of SFC and qNMR. This strategy provides an efficient, green, and generalizable paradigm for the accurate quantification of low-purity organic compounds in chiral drugs and complex matrices.

Human myoglobin (hMYO) is a sensitive early biomarker for acute myocardial infarction, rising within 1 3 h after myocardial injury and offering high predictive value for excluding infarction. To standardize its measurement, a precise quantitative method combining magnetic bead extraction with liquid chromatography–isotope dilution tandem mass spectrometry (LC‑IDMS/MS) was established. 15NLabeled myoglobin was spiked into serum as an internal standard, and magnetic beads coated with monoclonal antibodies (mAbs) against hMYO were used for the extraction of hMYO from serum. The mAb employed in this study demonstrated comparable binding affinity for both native myoglobin and its isotopically labeled counterpart, as confirmed by surface plasmon resonance measurements. After extraction, the magnetic beads were washed and digested, and two signature peptides, VEADIPGHGQEVLIR (VR) and HGATVLTALGGILK (HGK), were selected for quantification of hMYO. The incubation time, bead and enzyme amounts, and digestion time were optimized to establish optimal sample treatment conditions. Digested peptides were analyzed by LC‑IDMS/MS and recovery based on the VR peptide was 95.4–101.6

Enzyme immobilization represents a critical approach to address enzyme instability and limited recyclability in practical biocatalytic systems. However, simultaneously improving enzyme stability and catalytic activity remains a major bottleneck, restricting the broader implementation of immobilized enzymes. Herein, we report a mild in situ encapsulation strategy using layered double hydroxides (LDHs) as a structurally tailored host matrix for enzyme confinement. Benefiting from the hydrophilic and layered structure of MgAl-LDH, the HRP@MgAl-LDH composite preserved the native conformation of encapsulated HRP while delivering exceptional structural stability. The MgAl-LDH not only created a biocompatible microenvironment that sustained high enzymatic activity but also acted as a protective scaffold to enhance stability and reusability. Electrochemical characterization revealed that HRP@MgAl-LDH promoted rapid and efficient electron transfer between the enzyme active sites and the electrode surface, enabling faster reaction kinetics relative to free HRP and conventionally immobilized enzyme systems. Leveraging these favorable structural and electrochemical properties, we fabricated a portable electrochemical sensor for the sensitive detection of H2O2 in human urine. The sensor exhibited a wide linear detection range (50 pM-250 μM) and a low detection limit of 36.96 pM, along with rapid response, strong anti-interference performance, portability, and low cost. This LDH-based in situ encapsulation strategy effectively balanced the often-competing demands of high enzymatic activity and long-term stability, overcoming key limitations of traditional encapsulation methods. This work offered a promising high conductive material-based strategy for the development of practical point-of-care devices for H2O2 detection in complex biological samples.

Abstract Peptide bond hydrolysis plays a crucial role in protein structure determination. As promising alternatives to natural enzymes, nanoproteases have garnered substantial attention for overcoming their inherent limitations. However, the catalytic performance of most reported nanoproteases remains unsatisfactory, primarily due to their insufficient catalytic activity. In this work, a two-dimensional bimetallic metal–organic framework (2D MOF, CeCuBDC) is developed as a highly efficient nanoprotease for peptide bond hydrolysis. The catalytic mechanism and the hydrolysis pathway are systematically investigated by comprehensive experiments and characterizations. The 2D MOF maximizes active site accessibility and reduces mass-transfer resistance. Meanwhile, bimetallic doping and the electron-withdrawing effect of the organic ligand further enhance the Lewis acidity of metal sites, thereby significantly promoting the catalytic performance toward peptide bond hydrolysis. Moreover, the organic ligand promotes protein conformational changes via hydrophobic interactions, exposing more protein cleavage sites and accelerating the hydrolysis rate. Consequently, the CeCuBDC nanoprotease exhibits a 3–5-fold enhancement in protein hydrolysis efficiency relative to conventional proteases reported in the literature. The as-prepared CeCuBDC exhibits excellent stability and recyclability during protein hydrolysis. Furthermore, it displays high efficiency toward the hydrolysis of various proteins and protein mixtures, while showing a preference for cleaving peptide bonds containing hydrophobic residues. This study enables the rational design of nanoproteases with superior hydrolytic activity and relative selective cleavage ability, offering new strategies for constructing high-performance nanoproteases toward applications in proteomic research.

Low-molecular-weight proteins (LWPs, <30 kDa) are crucial in the identification of tumor markers and disease diagnosis. However, current methods for analyzing LWPs typically involve complex workflows, high sample consumption, poor automation, and prolonged reaction times. In this study, immobilized enzyme microreactors (IMERs) were prepared by immobilizing trypsin encapsulated in zeolitic imidazolate frameworks (ZIF-L) within a capillary, which was then integrated with capillary electrophoresis (CE) to develop a novel strategy for the pretreatment and assay of LWPs. Compared to traditional LWP analysis protocols, which typically involved a three-step process of sequential separation, denaturation, and enzymatic digestion, the proposed strategy achieved the LWP analysis in a single step within just 4 min in a 10 μL sample, significantly reducing sample pretreatment procedures and analytical time while offering advantages such as high efficiency, rapid processing, automation, and low consumption. The prepared trypsin@ZIF-L@IMER exhibited superior activity, enhanced affinity, remarkable stability, and excellent reusability when compared with free enzyme. In addition, the trypsin@ZIF-L@IMER demonstrated high selectivity toward LWPs after the pretreatment of single, binary, quaternary, and septenary model proteins. Additionally, the development method demonstrated ultrahigh sensitivity (0.05 nM cytochrome c (CYC)) and excellent anti-interference capability (CYC/bovine serum albumin (BSA) = 1:1000), outperforming previously reported methods. Finally, the developed strategy based on trypsin@ZIF-L@IMER was used for LWP analysis in human serum. The results showed that trypsin@ZIF-L@IMER possessed higher selectivity and pretreatment capability toward LWPs in human serum when compared with other methods and free trypsin, and the identified LWPs played critical functions and roles in serum-related biological processes by Gene Ontology analysis. The developed method provides a novel strategy for efficient protein pretreatment analysis, which can be further extended to the pretreatment analysis of other proteins.

Against the strategic backdrop of the implementation of the Basic Discipline Talent Training Plan 2.0 and the Chemistry"101 plan",integrating new concepts,content,and methodologies into core course teaching is the key to improving the quality of talent cultivation.To address the problems existing in the teaching of atomic spectrometry,such as fragmented knowledge systems,abstract concepts,and the disconnection between theory and practice,this paper systematically elaborated on the teaching reform and practice of atomic spectrometry for the cultivation of innovative talents in chemistry.The reform was discussed from four dimensions:reconstruction of teaching content,innovation of teaching methods,integration of teaching resources,and integration of ideological and political educa-tion into courses.The teaching content was categorized into three levels—basic core,advanced integration,and extended frontier—to construct a modular knowledge system.For teaching methods,a diversified model incorporating the comparative method,heuristic interaction,and case-based learning was adopted to strengthen the cultivation of students'autonomous learning and innovative abilities.Multidimensional teaching resources,including textbooks,digital resources,and scientific research cases,were integrated to expand the boundaries of learning.Ideological and political elements such as patriotism and the scientific spirit were organically integrated into the entire teaching process,so as to achieve the synergistic integration of knowledge imparting,competence development,and value guidance.The relevant research findings and practical achievements are expected to provide valuable references for the teaching reform of analytical chemistry and related courses.

Phosphoproteomics research is crucial for clinical diagnosis. However, due to the self-hydrolysis of natural proteases and the complex typical pretreatment protocol, the traditional bottom-up method is not enough to achieve rapid analysis of phosphorylated proteins. In this work, we encapsulate trypsin (Try) in the ZIF-L(Co) to develop a new strategy that simplifies the phosphorylated protein analysis process and achieves rapid analysis. Try is encapsulated in the mesoporous ZIF-L(Co) to allow the proteins to be accessible to the enzymes. The hydrophobic ZIF-L(Co) can cause the unfolding of proteins and accelerates the digestion process. The Co(II) nodes enhance the affinity toward phosphorylated proteins and capture phosphopeptides selectively. Compared to the traditional denaturation, digestion, and enrichment method, which costs 20 h at least, our strategy simplifies the pretreatment workflow and yields phosphopeptides in just 3.4 h. This strategy is further applied in the analysis of phosphorylated proteins in biosamples such as nonfat milk, egg yolk, and human serum. The results show equivalent performance with the traditional method and exhibit great potential in bioanalysis. This new phosphorylated protein analysis strategy provides a powerful tool for proteomics analysis and promotes research in the field of biomedicine.

In this study, novel covalent/metal-organic skeleton composites (TpBD@MIL-68; 2,4,6-triformylphloroglucinol (Tp) and benzidine (BD)) were combined with high-performance liquid chromatography (HPLC) and used to develop a method for detecting ultraviolet absorbers, including 4-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,3-diol (Appolo-116), 3-benzenediol, 4-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-1 (DBDT), 2,4,6-triphenyl-s-triazine (TPTZ), 2,4,6-trip-tolyl-1.3.5-triazine, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-((hexyl)oxy)phenol (UV-1577), and 2-(4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(octyloxy)-phenol (UV-1164) is present in greenhouse films and soils. TpBD@MIL-68 has the unique characteristics of a covalent organic framework and a metal-organic framework. TpBD@MIL-68 exhibited a higher extraction efficiency because of π-π and electrostatic interactions between the benzene ring structure of the TpBD, MIL-68, and the ultraviolet absorber molecules. The extraction conditions, including the adsorbent dosage, eluent type and dosage, elution time, and the pH of the sample solution, were fully optimized. The extraction efficiency of TpBD@MIL-68 exceeded 80%. The detection results showed good linearity over a wide range of concentrations (5-5000 µg/L) and low detection limits (0.61-0.94 ng/mL) for target molecules. The practicability of this solid-phase extraction (SPE)-HPLC method was further evaluated by analyzing greenhouse films and soils, with target recoveries of 80.9%-109.9% and relative standard deviations of less than 8.9%. The as-synthesized TpBD@MIL-68 adsorbent exhibited great potential in ultraviolet absorber analysis.

Glycopeptides are an important biomarker, which play a crucial role in various biological processes. Due to their low abundance and the presence of interfering macromolecular proteins, enrichment of glycopeptides is necessary before testing. However, most materials for enriching glycopeptides have high site resistance, relatively low surface area, and limited recognition sites. Herein, a highly hydrophilic two-dimensional (2-D) covalent organic framework (NUS-10) loaded with chitosan (CS) (denoted as NUS-10@CS) had been synthesized. After enrichment with NUS-10@CS, a total of 34 glycopeptides from horseradish peroxidase (HRP) tryptic digests were detected, demonstrating a high enrichment efficiency for glycopeptides from model glycoprotein digestion. Meanwhile, the material exhibited ultra-high adsorption capacity (1 fmol/μL HRP), excellent selectivity (HRP tryptic digest/bovine serum albumin (BSA) tryptic digest = 1:2000), macromolecular protein anti-interference ability (HRP tryptic digest/BSA = 1:2000) and good binding capacity (200 mg/g). Additionally, 712 glycopeptides corresponding to 200 glycoproteins were identified from 3 µL human serum. NUS-10@CS was promising for glycopeptide analysis, helping to identify potential disease biomarkers more efficiently, and leading to easier and more accurate diagnosis of diseases, which was essential for early intervention and treatment.

In the biomedical and chemical fields, purity assessment of compounds is a critical step in ensuring product quality and safety. In this study, a method for purity quantification was proposed as two-signal suppression–internal standard correction–high-performance liquid chromatography–quantitative nuclear magnetic resonance (TSS-ISC-HPLC-qNMR). The two-signal suppression effectively suppresses the interference of solvent signals in the NMR spectra, and the internal standard correction eliminates the influence of many variables during sample preparation and analysis. The purity result (99.89

The ingenious design of active sites in mimetic enzymes is crucial for developing enzyme-like functional materials with high activity and selectivity. Inspired by the N-ligand-rich copper centers of natural laccase, a novel laccase-like nanozyme was developed by loading copper ions into zeolite imidazolate framework-8 (Cu/Zn-ZIF). Benefiting from the precise mimicry of the catalytic center and the high dispersion of catalytic sites which were supported by the MOF backbone, Cu/Zn-ZIF manifested superior laccase-like activity. Notably, its substrate affinity and catalytic efficiency were substantially higher compared to those of natural laccase. More importantly, experimental results proved that the catalytic mechanism of Cu/Zn-ZIF was similar to that of natural laccase. In addition, Cu/Zn-ZIF nanozyme presented commendable stability under various harsh conditions compared to natural laccase. Surprisingly, limited by the pore size, Cu/Zn-ZIF exhibited the selectivity for different sizes substrates which was not found in natural laccase. As a proof of concept application, a colorimetric detection platform for 4-methoxyphenol was constructed with a broad linear range (1-150 μg/mL) and a low limit of detection (0.33 μg/mL). This study provides a novel approach for the rational design of nanozymes and serves as a feasible reference for enriching the application scenarios of laccase-like nanozymes.

Nanozymes are attracting widespread attention as effective alternatives to overcome the limitations of natural enzymes. However, their catalytic performance is unsatisfactory due to the low catalytic activity and specificity. In this work, an efficient metal-organic framework (MOF) nanozyme mimicking the active centers of natural enzymes has been developed and its catalysis mechanism has been thoroughly investigated. The partial histidine- and arginine-doped Fe-MOF (HA Fe-MOF) is demonstrated to activate structure reconstruction with abundant oxygen vacancy generation, which promotes the binding capacity of HA Fe-MOF. The Fe sites in HA Fe-MOF act as catalytic sites for decomposition of H2O2. Intriguingly, histidine and arginine in the HA Fe-MOF can form hydrogen bonds with H2O2 as observed in natural enzymes, constituting a unique microenvironment that increases the local concentration of H2O2. Benefiting from the establishment of such enzyme-mimicking active centers, HA Fe-MOF exhibits high peroxidase-like specificity and activity. In addition, HA Fe-MOF holds great potential for detecting uranyl ions with a limit of detection as low as 0.012 μM, surpassing most reported nanozymes. This work achieves the rational design of highly specific peroxidase-like nanozymes by mimicking the structure-selectivity relationship of natural peroxidases, which provides new insights into the design of nanozymes with advanced configurations.

Angiotensin I, II, and III (Ang I, II, and III) and aldosterone (Aldo) play an important role in primary aldosteronism (PA) screening according to the study of the blood pressure regulation mechanism. However, Ang I, Ang II, Ang III, and Aldo are present in human plasma at low concentrations and have different polarities, which make it rather challenging for current detection methods to simultaneously detect four analytes in complex blood samples. In this study, a new magnetic covalent organic framework (COF) was synthesized for the enrichment of Ang I, II, and III and Aldo in human plasma, and a new method for the simultaneous detection of four analytes was developed based on the magnetic COF and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The experimental results demonstrated that the adsorption kinetics of the material conformed to a pseudo-second-order model, and the enrichment mechanisms were π-π stacking, electrostatic, and hydrogen bonding interactions. Under the optimized conditions, the established method has satisfactory linear ranges (Ang I: 100-25,000 pg/mL, Ang II: 2-500 pg/mL, Ang III: 3-750 pg/mL, and Aldo: 20-5000 pg/mL), a low limit of detection (0.8-5 pg/mL), high recoveries (93.0-111.3%), and multiple recycling, which were superior to those reported studies. Meanwhile, the results of testing 20 clinical samples indicated that Ang I, Ang II, Ang III, and Aldo were effective and could be used as new biomarkers for PA screening, which proved the feasibility of enriching the four targets in real blood samples. The prepared magnetic COF in this experiment provided a reference for the material design to simultaneous enrichment of Ang I, Ang II, Ang III, and Aldo, and the developed new method based on the magnetic COF and LC-MS/MS provided a new detection idea for PA screening, which greatly promoted the development of PA disease diagnosis and was expected to be used in further clinical research.

The present work assessed the purity of [Glu(1)]-fibrinopeptide B (GFB) as a model peptide using gas chromatography - isotope dilution mass spectrometry. GFB and various isotope-labeled amino acids were hydrolyzed in HCl and then derivatized using optimized procedures. The primary impurity in GFB was also identified and used to correct the final result. A method repeatability of 0.5% was achieved and linear calibrations were obtained for five amino acids. The LOD and LOQ were 0.041 to 0.096 mu g g(-1), and 0.16 to 0.56 mu g g(-1), respectively. The purity of GFB was found to be (0.715 +/- 0.012) g g(-1). This technique exhibited comparable accuracy to that obtainable from liquid chromatography - isotope dilution mass spectrometry but at lower cost. This method could be employed as a reference technique or in fields such as clinical diagnostics or bio-pharmaceutical peptide purity analysis.

In this work, a novel electrospun nanofiber (PAN/TpBD; 2,4,6‐triformylphloroglucinol [Tp] and benzidine [BD]; polyacrylonitrile [PAN]) was fabricated via a facile electrospinning method and utilized as adsorbent in thin film microextraction (TFME) of phthalate esters (PAEs) (dimethyl phthalate, diethyl phthalate, diallyl phthalate, dibutyl phthalate, and dioctyl phthalate) in biodegradable plastics. The prepared PAN/TpBD combines the strong stability of nanofibers with increased exposure sites for covalent organic frameworks and enhanced interactions with the target, thus improving the enrichment effect on the target. The extraction efficiency of PAN/TpBD reached above 80%. Based on PAN/TpBD, a TFME‐high‐performance liquid chromatography method was established, and the experimental parameters were optimized. Under the optimal extraction conditions, the PAEs of this method varied linearly in the range of 10–10 000 µg/L with low detection limits (0.69–2.72 µg/L). The intra‐day and inter‐day relative standard deviation values of the PAEs were less than 8.04% and 8.73%, respectively. The adsorbent can achieve more than 80% recovery of the five targets after six times reuse. The developed method was successfully applied for the determination of trace PAEs in biodegradable plastics with recoveries ranging from 80.1% to 113.4% and relative standard deviations were less than 9.45%. The as‐synthesized PAN/TpBD adsorbent exhibited great potential in PAE analysis.

Low-molecular weight proteins (LWPs) are important sources of biological information in biomarkers, signaling molecules, and pathology. However, the separation and analysis of LWPs in complex biological samples are challenging, mainly due to their low abundance and the complex sample pretreatment procedure. Herein, trypsin modified by poly(acrylic acid) (PAA) was encapsulated by a zeolitic imidazolate framework (ZIF-L). Mesopores were formed on the ZIF-L with the introduction of PAA. An alternative strategy for separation and pretreatment of LWPs was developed based on the prepared ZIF-L-encapsulated trypsin with adjustable pore size. The mesoporous structure of the prepared materials selectively excluded high-molecular weight proteins from the reaction system, allowing LWPs to enter the pores and react with the internal trypsin, resulting in an improved separation efficiency. The hydrophobicity of the ZIF-L simplified the digestion process by inducing significant structural changes in substrate proteins. In addition, the enzymatic activity was significantly enhanced by the developed encapsulation method that maintained the enzyme conformation, allowed low mass transfer resistance, and possessed a high enzyme-to-substrate ratio. As a result, the ZIF-L-encapsulated trypsin can achieve highly selective separation, valid denaturation, and efficient digestion of LWPs in a short time by simply mixing with substrate proteins, greatly simplifying the separation and pretreatment process of the traditional hydrolysis method. The prepared materials and the developed strategy demonstrated an excellent size-selective assay performance in model protein mixtures, showing great potential in the application of proteomics analysis.

Along with an ever-deepening understanding of the catalytic principle of natural enzymes, the rational design of high-activity biomimetic nanozymes has become a hot topic in current research. Inspired by the active centers of natural enzymes consisting of catalytic sites and binding pockets, a Cu-doped CoS2 hollow nanocube (Cu/CoS2 HNCs) nanozyme integrating substitution defects and vacancies is developed through a defect engineering strategy. It is shown that the vacancies and substitution defects in the developed Cu/CoS2 HNC nanozymes serve as binding pockets and catalytic sites, respectively. The construction of this key active center and the accelerated electron transfer from the Co/Cu redox cycle significantly improve the substrate affinity and catalytic efficiency of the Cu/CoS2 HNCs nanozymes, which results in the excellent catalytic performance of the Cu/CoS2 HNC nanozymes. Using the superior enzymatic activity of Cu/CoS2 HNCs, a fluorescence detection platform for alkaline phosphatase (ALP) is established, which is a wider detection range and lower limit of detection (LOD) than previous work. This work broadens the family of nanozymes and provide a new idea for the development of novel nanozymes with high enzyme activity, as well as a guideline for the construction of highly sensitive fluorescent sensors.

Open-tubular immobilized enzyme microreactors (OT-IMERs) are some of the most widely used enzyme reaction devices due to the advantages of simple preparation and fast sample processing. However, the traditional approaches for OT-IMERs preparation had some defects such as limited enzyme loading amount, susceptibility to complex sample interference, and less stability. Here, we report a strategy for the preparation of highly active and stable OT-IMERs, in which the single-stranded DNA-enzyme composites were immobilized in capillaries and then encapsulated in situ in the capillaries via zeolitic imidazolate frameworks (ZIF-L). The phosphate groups of the DNA adjusted the surface potential of the enzyme to negative values, which could attract cations, such as Zn2+, to promote the formation of ZIF-L for enzyme encapsulation. Using chymotrypsin (ChT) as a model enzyme, the prepared ChT@ZIF-L-IMER has higher activity and better affinity than the free enzyme and ChT-IMER. Moreover, the thermal stability, pH stability, and organic solvent stability of ChT@ZIF-L-IMER were much higher than those of free enzyme and ChT-IMER. Furthermore, the activity of ChT@ZIF-L-IMER was much higher than that of ChT-IMER after ten consecutive reactions. To demonstrate the versatility of this preparation method, we replaced ChT with glucose oxidase (GOx). The stability of GOx@ZIF-L-IMER was also experimentally demonstrated to be superior to that of GOx and GOx-IMER. Finally, ChT@ZIF-L-IMER was used for proteolytic digestion analysis. The results showed that ChT@ZIF-L-IMER had a short digestion time and high digestive efficiency compared with the free enzyme. The present study broadened the synthesis method of OT-IMERs, effectively integrating the advantages of metal-organic frameworks and IMER, and the prepared OT-IMERs significantly improved enzyme stability. All of the results indicated that the IMER prepared by this method had a broad application prospect in capillary electrophoresis-based high-performance enzyme analysis.

Protein glycosylation research is currently focused on the development of various functionalized materials that can effectively enrich the levels of glycopeptides in samples. However, most of these materials possess limited glycopeptide-specific recognition sites because of large steric hindrance, unsuitable mass transfer kinetics, and relatively low surface areas. Herein, a highly hydrophilic two-dimensional (2-D) metal-organic framework (MOF) nanosheet modified with glutathione (GSH) and L-cysteine (L-Cys) (denoted as Zr-Fc MOF@Au@GC) has been synthesized for efficient glycopeptide enrichment. Using this composite material, 39 and 44 glycopeptides from horseradish peroxidase (HRP) and human serum immunoglobulin G (IgG) digests were detected, respectively, which represents a higher efficiency for glycopeptide enrichment from model glycoprotein digests than has been previously reported. The material Zr-Fc MOF@Au@GC exhibited ultra-high sensitivity (0.1 fmol/mu L), excellent selectivity (weight ratio of HRP tryptic digest to bovine serum albumin (BSA) tryptic digest = 1:2000), good binding capacity (200 mg/g), satisfactory reusability, and long-term storage capacity. In addition, 655 glycopeptides corresponding to 366 glycoproteins were identified from human serum samples. To the best of our knowledge, this is the largest number of glycoproteins detected in human serum samples to date. These results indicated that Zr-Fc MOF@Au@GC has the potential to be used for the enrichment of glycopeptides in biological samples and the analysis of protein glycosylation.

In this study, the coulometric method with titratable impurity analysis and the mass balance method were successfully applied in the quantification of the certified reference material of potassium hydrogen phthalate (KHP) with accurate metrological traceability of chemical purity value (99.983