The Application Of Coumarin Hydroxylamine Derivatization Reagent HAHC On The Analysis Of Low-molecular-mass Aldehydes

Many low-molecular-mass aldehydes are reported to be corrosive,irritating and have mutagenic and carcinogenic potentials,causing harmful effects to human health.Therefore,it is of vital importance to develop a sensitive and selective method for aldehydes analysis in various matrices,such as foods,environment and biological samples.In this thesis,a novel derivatizaiton method based on nitrone formation was developed and applied for the analysis of trace amounts of aldehydes in various samples.A synthetic coumarin N-substituted hydroxylamine reagent 4-((hydroxyamino)butyl)-7-hydroxycoumarin(HAHC)was used to label aldehydes through nitrone formation reaction,affording stable trans-form nitrone derivatives with good fluorescent properties.The following HPLC-FLD analysis allowed the determination of aldehydes with high sensitivity and selectivity.The main results were summarized below:(1)HAHC was applied to label three furfurals(furfural,5-methylfurfural and 5-hydroxymethylfurfural)through their aldehyde groups base on nitrone formation reaction.The derivatization can happen in aqueous condition at room temperature with high derivatization efficiencies(Y ? 93%),making it a simple and ease of automation way for aldehyde detection in real samples.Using this method,the determination of 3 furfurals in food samples was falicitatied with high sensitivity(0.1-0.8 nM)and good recovery(94.7%-103.5%).Compared with the conventional detection methods,the established method highlights several advantages,such as mild reaction conditions,no complicated pre-treatment steps,ease of automation and low limit of detection.(2)A qualitative and quantitative analysis of eight aliphatic aldehydes(ethanal,propanal,butanal,petanal,hexanal,heptanal,octanal and nonanal)in water samples was established.In this method,water samples were simply filtrated and mixed with HAHC solution.The mixture was kept at room temperature for 30 min and was then directly sent for HPLC-FLD analysis.The results showed that this method was sensitive and selective,allowing the simultaneous detection of eight aliphatic aldehydes with low detection limits in the range of 0.2-2.0 nM.Finally,the method was applied for aldehydes detection in different water samples(tap water,lake water,swimming pool water and rainwater).The results showed that aldehydes concentrations in natural waters(rain water,lake water)were higher than those in the processed waters(swimming pool water,tap water),indicating the importance of aldehyde monitoring in wet depositions.(3)The HAHC derivatization method was further applied for aldehydes detection in human serums.The serum samples were obtained from diabetics,hypertensive patients and healthy people.5 aldehydes(acetaldehyde,propanal,butanal and nonanal)were successfully detected within all the samples.The acetaldehyde concentrations in diabetics or hypertensive patients were obviously higher than those in the control,suggesting the correlation between endogenous aldehydes and cardiovascular diseases.