RÉSUMÉ
Fluorescence anisotropy(FA)analysis has many advantages such as no requirement of separation,high throughput and real-time detection,and thus has been widely used in many fields,including biochemical analysis,food safety detection,environmental monitoring,etc.However,due to the small volume or mass of the target,its combination with the fluorescence probe cannot produce significant signal change.To solve this issue,researchers often use nanomaterials to enhance the mass or volume of fluorophore to improve the sensitivity.Nevertheless,this FA amplification strategy also has some disadvantages.Firstly,nanomaterials are easy to quench fluorescence.As a result,the FA value is easily influenced by light scattering,which reduces the detection accuracy.Secondly,fluorescent probes in most methods require complex modification steps.Therefore,it is necessary to develop new FA probes that do not require the amplification of volume and mass or modification.As a new kind of nanomaterials,luminescent metal-organic framework(MOF)has a large volume(or mass)and strong fluorescence emission.It does not require additional signal amplification materials.As a consequence,it can be used as a potential FA probe.This study successfully synthesized a lanthanide metal organic framework(Ce-TCPP MOF)using cerium ion(Ce3+)as the central ion and 5,10,15,20-tetra(4-carboxylphenyl)porphyrin(H2TCPP)as the ligand through microwave assisted method,and used it as a novel unmodified FA probe to detect phosphate ions(Pi).In the absence of Pi,Ce-TCPP MOF had a significant FA value(r).After addition of Pi,Pi reacted with Ce3+in MOF and destroyed the structure of MOF into the small pieces,resulting in a decrease in r.The experimental results indicated that with the increase of Pi concentration,the change of the r of Ce-TCPP MOF(Δr)gradually increased.The Δr and Pi concentration showed a good linear relationship within the range of 0.5-3.5 μmol/L(0.016-0.108 mg/L).The limit of detection(LOD,3σ/k)was 0.41 μmol/L.The concentration of Pi in the Jialing River water detected by this method was about 0.078 mg/L,and the Pi value detected by ammonium molybdate spectrophotometry was about 0.080 mg/L.The two detection results were consistent with each other,and the detection results also meet the ClassⅡwater quality standard,proving that this method could be used for the detection of Pi in complex water bodies.
RÉSUMÉ
Ultra-high performance liquid chromatography-quadrupole-Exactive Orbitrap high resolution mass spectrometry(UHPLC-Q-Exactive Orbitrap HRMS) was employed to systematically analyze the chemical constituents in Lysionoti Herba, and high perfor-mance liquid chromatography-ultraviolet(HPLC-UV) to determine the content of main compounds. A Synergi~(TM) Hydro-RP 100 Å colu-mn(2 mm×100 mm, 2.5 μm) was used for gradient elution with acetonitrile-0.1% aqueous formic acid as the mobile phase at a flow rate of 0.2 mL·min~(-1) and a column temperature of 40 ℃. MS and MS/MS were conducted with electrospray ionization(ESI) in both positive and negative modes. The chemical components in Lysionoti Herba were identified by comparison with the retention time and mass spectra of reference compounds and the relevant mass spectral data reported in MS databases and relevant literature. Furthermore, the content of five constituents(neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin) in different Lysiono-ti Herba samples was simultaneously determined by HPLC-UV at the wavelength of 330 nm. A total of 84 compounds were identified in Lysionoti Herba, including 27 flavonoids, 20 phenylethanoid glycosides, 5 amino acids, 18 organic acids, 1 alkaloid, 6 nucleosides, and 7 others. The content of neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin showed good linear relationship(r>0.999) with the peak area within certain concentration ranges, which were 3.22-102.90, 12.84-410.82, 31.63-1 012.01, 25.00-800.11, and 4.08-130.51 μg·mL~(-1), respectively. The instrument precision, method repeatability, and solution stability all met requirement, and the average recovery rate was 97.31%-100.2%, with RSD ranging from 0.95% to 2.4%. The content of the five components varied among different Lysionoti Herba samples collected from different regions of Guizhou, and the average content of forsythoside B was the highest. The established qualitative method can rapidly and efficiently identify the chemical components of Lysionoti Herba, and the developed HPLC-UV method can simultaneously determine the content of five components in a simple, ra-pid, and accurate manner, providing a scientific basis for the quality evaluation of Lysionoti Herba.