Application Of Ferroferric Oxide/Nitrogen-doped Graphene In Determination Of Carbonyl Compounds

Carbonyl compounds exit in water and air widely,which are toxic and harmful to human health.They are also metabolites in human,and studies have shown that hexanal and heptanal can be used as biomarkers for lung cancer.However,the present sample pre-treatments in determination of carbonyl compounds have some disadvantages such as high consumption of organic solvents,cumbersome operation,and difficulty in removing derivatization reagents.It is important and significant to establish a simple,rapid,accurate and sensitive method for the determination of carbonyl compounds.In this study,simple and sensitive magnetic solid-phase extraction procedures with ferroferric oxide/nitrogen-doped graphene nanomaterials?Fe₃O₄/N-G?as the magnetic adsorbent have been developed to determine carbonyl compounds in environmental water samples and human urine samples,by investigating the adsorption performance of Fe₃O₄/N-G,derivation conditions and magnetic solid-phase extraction conditions.The main content includes following two parts:Firstly,Fe₃O₄/N-G nanomaterials were synthesized by chemical co-precipitation method,which were characterized by XRD,SEM and VSM.In combination with2,4-dinitrophenylhydrazine?DNPH?pre-column derivatization,an ultrasound-assisted magnetic solid phase extraction with Fe₃O₄/N-G as the magnetic adsorbent has been developed for the determination of acetone,acrolein,butenal,n-butanal,cyclohexanone and hexanal in environmental water samples,coupled with ultra-performance liquid chromatography-high resolution mass spectrometry.The results of adsorption of 6 phenylhydrazone derivatives on Fe₃O₄/N-G showed that the adsorption capacity was above 210 mg/g.Then the derivation conditions and magnetic solid-phase extraction conditions were optimized.As a result,the conversion ratios of 6 carbonyl compounds were in the range of 52.1%-86.6%and the excessive DNPH could be almost eliminated by the MPSE process obviously.Under the optimal conditions,a good linearity was obtained in the concentration range of2-100 ng/L,with the correlation coefficients ranging from 0.9980 to 0.9995.The limits of detection?LOD?and the limits of quantity?LOQ?ranged from 0.05 to 0.20ng/L and 0.20 to 0.96 ng/L,respectively.The average recoveries at three spiked levels ranged from 74.1%to 101.0%with the inter-and intra-day precisions?n=6?less than6.3%.Moreover,the trace level of acetone,acrolein,butenal,n-butanal,and hexanal in real water samples has been successfully detected using the proposed method.Attributed to the excellent performances of Fe₃O₄/N-G,the proposed method was demonstrated to be simple,quick and high sensitive for the trace analysis of carbonyl compounds in water samples.However,the derivatization efficiency was low in this method,and it was limited in practical applications of this method because of the high polarity of phenylhydrazone derivatives.Secondly,an ultrasound-assisted magnetic solid phase extraction with Fe₃O₄/N-G as the magnetic adsorbent has been developed for the determination of n-butanal,butenal,pentanal,hexanal,heptanal,octanal and nonanal in human urine by gas chromatography coupled to tandem mass spectrometry with O-?2,3,4,5,6-Pentafluoro-benzyl?hydroxylamine hydrochloride?PFBHA?pre-column derivatization.The results of adsorption of 7 oxime derivatives on Fe₃O₄/N-G showed that the adsorption capacity was above 107 mg/g.Then the derivation conditions and magnetic solid-phase extraction conditions were optimized.As a result,the conversion ratios of7 aldehydes were over 82%,and the excessive PFBHA could be almost eliminated by the MPSE process obviously.Under the optimal conditions,a good linearity was obtained in the concentration range of 5-500 nmol/L,with the correlation coefficients ranging from 0.9980-0.9996.The LOD and LOQ ranged from 0.16 to 0.49 nmol/L and 0.55 to 1.67 nmol/L,respectively.The average recoveries at three spiked levels ranged from 65.8%to 106.7%with the inter-and intra-day precisions?n=6?less than6.2%.The matrix factor is between 87.0%and 119.6%.Moreover,the developed method has been successfully applied to the analysis of aldehydes in urine samples of42 healthy people,29 lung cancer patients and 39 colorectal cancer patients.The results showed that the concentration of aldehydes in lung cancer patients and colorectal cancer patients were slightly higher than that in healthy humans,while the concentration of hexanal and heptanal in lung cancer patients were significantly higher than that in colorectal cancer patients and healthy humans.The method possessesd the advantages of simplicity,high derivatization efficiency,low sample consumption and sensitivity,it provides an alternative tool for the determination of aldehydes in urine samples.