The Analytical Application Of Fluorescent Probe Titration In Environment Pollutants And Drugs

Supramolecular chemistry is based on the formation ofnon-covalent intermolecular interactions. The molecular aggregateschemistry, has been extensively studied in recent years in the field ofmolecular switches, molecular catalysis, drug carriers, however,environmental pollutants, drugs guest molecules competitive withthe the supramolecular body cavity slow progress, especially in thenew generation the supramolecular cucurbit[n]uril maindetermination of environmental pollutants and drugs, more rarelyreported in the literature. In recent years, it has been caused seriouspollution of the environment and harmed the enormous humanbecause of a large number of environmental pollutants has beenabused, So it causes more and more people’s attention. While the drugis also of great significance for human health, so the establishment ofa high sensitivity, the high selectivity of the method of determinationof the content of these substances is the analysis of the need for urgent study of the environment and the drug. The interactionbetween cucurbit[n]uril and drugs was confirmed via the fluorescenceprobe titrated, the theories titration method etc. Newspectrofluorimetric methods with high sensitivity and selectivitywere developed for the determination of conventional fluorescencemethod no fluorescence environmental pollutants and drugs, and toexplore the established method used to determine the actual sampleof environmental pollutants and drugs. The proposed method hadbeen successfully applied to the determination of environmentalpollutants and non-fluorescent drugs in its samples with goodprecision and accuracy. The content of this paper are as follows:Chapter1: Supramolecular chemistry, fourth-generationsupramolecular cucurbit[n]uril of structural features and theirapplications in different fields were introduced, and basedcucurbit[n]uril main fluorescence spectroscopy and fluorescenceprobe method research progress were comprehensively reviewed.The development of the spectrofluorometry and the fluorescentprobe in the applications of pharmaceutical analytical also wereintroduced. This study focuses on the cucurbit[7]uril isoquinolinealkaloids structure and structural features, and guest moleculesand cucurbit[7]uril interaction between research and the different guest molecules cucurbit[7]uril cavity competitive research wasreviewed.Chapter2: Paraquat （PQ）, which is a nonselective herbicide,is non-fluorescent in aqueous solutions. Thus, its determinationthrough direct fluorescent methods is not feasible. The packetinteractions PQ hoist [7], the urea （CB [7]） was studied by afluorescent probe titration method. Significant quenching of thefluorescence intensity of the cucurbit[7]uril-coptisine （CB[7]-COP）fluorescent probe was observed with the addition of PQ. A newfluorescent probe titration method with high selectivity andsensitivity at the ng/mL level was developed to determine PQ inaqueous solutions with good precision and accuracy based on thesignificant quenching of the supramolecular complex fluorescenceintensity. The proposed method was successfully used in thedetermination of PQ in lake water, tap water, well, and ditch waterin an agricultural area, with recoveries of96.73%to105.77%. Thefluorescence quenching values （ΔF） showed a good linearrelationship with PQ concentrations from1.0×10^-8to1.2×10^-5mol/L with a detection limit of3.35×10^-9mol/L. In addition, theinteraction models of the supramolecular complexes formedbetween the host and the guest to establish a theoretical calculation. Interactive mechanism of between the cucurbit[7]uriland PQ was confirmed by1H NMR spectroscopy.Chapter3: The supramolecular inclusion interaction of thepesticides acetamiprid （AD） with cucurbit[7]uril （CB[7]） was studiedby a fluorescent probe titration method. Significant quenching ofthe fluorescence intensity of the cucurbit[7]uril-palmatinehydrochloride （CB[7]-PAL） fluorescent probe was observed with theaddition of AD. The hydrophobic interaction between contributed tothe formation of CB[7] and AD form a1:1CB [7]-AD. Its complexconstant was determined to be K=（1.29±0.09）×10¹¹M^-1. A newfluorescent probe titration method with high selectivity andsensitivity was developed to determine AD in aqueous solutionswith good precision and accuracy based on the significantquenching of the supramolecular complex fluorescence intensity.The fluorescence quenching values （ΔF） showed a good linearrelationship with PQ concentrations from0.015to1.6μg mL^-1with adetection limit of0.00497μg mL^-1. The proposed method wassuccessfully used in the determination of AD in the vegetables andfruits, with recoveries of98.75%to103.64%. In addition, theinteraction models of the supramolecular complexes formedbetween the host and the guest were established via theoretical calculations. Interactve of mechanism between the cucurbit[7]uriland AD was confirmed by theoretical calculations.Chapter4: The supramolecular interaction betweenpalmatine （PAL） and cucurbit[7]uril （CB[7]） was studied. Thoughthe weak fluorescence CB[7] with PAL interaction， they can form astable1:1host-guest complex. The fluorescence intensity of thecomplex enhanced gradually with the increase of CB[7]concentration. At the same time produced a strong fluorescenceemission, the association constant (K=1.25×10⁵Lmol^-1 wascalculated by applying a deduced equation. From the temperaturedependence of the equilibrium constants, thermodynamicsparameters H and S values were obtained, indicating an enthalpicdriving force for complexation. Molecular modeling calculationswere optimized at the B3LYP/6-31G（d） level of density functionaltheory using the Gaussian03program. In the energy-minimizedstructure, the methoxy-isoquinoline moiety is embedded in CB[7],and the heterocyclic nitrogen is located in the vicinity of acarbonyl-laced portal. Two hydrogen bonds are formed between theheterocyclic nitrogen and carbonyl oxygen of CB[7]. In addition, Anew fluorescent method with high selectivity and sensitivity wasdeveloped to determine carbachol in aqueous solutions with goodprecision and accuracy based on the significant quenching of the supramolecular complex fluorescence intensity. The linear range ofthe method was0.03～4.0μg mL–1with a detection limit of0.01μgmL–1. The proposed method was successfully applied for thedetermination of the drug in urine and serum samples.