Determination Of Cetylpyridinium Chloride,benzalkonium Bromide And Tetracaine Hydrochloride By Fluorescence Probe Method

Fluorescence spectroscopy has been widely used with the characteristics of high sensitivity,selectivity and ease of operation.However,some organic drug molecules have no fluorescence,it can not be directly measured by fluorescence spectroscopy.In this paper,the competitive reaction between some organic drug molecules and fluorescent probe in the cavity of cucurbit[7]urea was studied through the fluorescent probe system formed by the fourth generation supramolecular host cucurbit[7]urea(CB[7])and natural isoquinoline alkaloid Palmatine hydrochloride(PAL).It was found that some no-fluorescent organic drugs could produce strong quenching effect on CB[7]-PAL fluorescent probe system,such as cetylpyridinium chloride,benzalkonium bromide and tetracaine hydrochloride,and the concentration of drugs and the rate of fluorescence quenching of the fluorescent probe system showed a good linear relationship.Based on the above facts,a series of fluorescence spectroscopy methods were proposed for the determination of cetylpyridinium chloride,benzalkonium bromide and tetracaine hydrochloride,resepactively.These methods have several advantages,including simple operation,high efficiency,good selective and high sensitivity.And they were applied to the detection of target drugs in pharmaceutical preparations,blood samples and urine samples with satisfactory determination results.In addition,the competitive reaction mechanisms between the three drug molecules and probes in the cavity of CB[7] were investigated by fluorescence spectroscopy,UV spectroscopy and1 H NMR.It can be seen that the binding constants of the three drug molecules and CB[7] are greater than CB[7]-PAL.Therefore,the probe molecules are squeezed out of the cavity owning to the competitive reaction to quench the fluorescence of the probe.Finally,the molecular model of the interaction between drugs and supramolecular was established by the density functional theory calculations.This paper can be divided into four parts:1.In this part,the research progress of synthesis,molecular structure,molecular recognition,molecular assembly and molecular devices of the fourth generation supramolecular main body of CB[n] was introduced.And the recent development andsituation of fluorescence enhancement method and the fluorescence quenching method by using CB[n] as the subject were briefly introduced.2.Cetylpyridinium chloride(CPC)had no fluorescence,and there was no any method for the determination of CPC by fluorescence spectrometry in the literature.CB[7]-PAL is a probe system,which can emit strong fluorescence.With the addition of CPC,the fluorescence intensity decreased significantly.And the quenching value is proportional to the concentration of CPC in a certain range.Based on the results,a fluorescence spectrum method was proposed for the detection of CPC.The supramolecular mechanism was discussed by some advanced techniques,and the binding constants of CB[7]-CPC supramolecular inclusion complexes were calculated.3.The inclusion reaction of benzalkonium bromide(BKB)and CB[7] in acidic solution was studied by fluorescence spectroscopy.BKB itself have no fluorescence,but there is a competitive reaction between PAL and the CB[7] hydrophobic cavity,resulting fluorescence quenching of the CB[7]-PAL system.And the quenching value showed a good linear relationship with the concentration of BKB.Therefore,a new method was established for the determination of BKB with high sensitivity,good selectivity and reproducibility.4.The interaction between tetracaine hydrochloride(TCH)and CB[7] was studied by fluorescence spectroscopy,UV spectroscopy and 1H NMR.And a novel method for the determination of TCH by PAL,as fluorescent probe,was established.The results showed that the sensitivity of the method was higher than other analysis methods,which were reported in the literature.Moreover,the method can be used for the determination of TCH in pharmaceutical preparations and blood samples.In addition,the molecular model of the interaction between TCH and CB[7] was established by density functional theory.