| The detection of food and environmental samples has the characteristics of large sample amount,and the pretreatment steps are complex and time-consuming.Therefore,a rapid and efficient detection method of volatile compounds in food and environmental samples is needed.The atmospheric pressure ionization(API)technology is directly coupled with high-resolution mass spectrometry and has the characteristics of strong resolution,wide application,fast and accurate.This paper aims to establish a direct injection analysis method based on atmospheric piezoelectric ionization and high resolution mass spectrometry to analyze volatile compounds in food and environment.In this research,the direct inlet probe(DIP)was coated with hydroxy-terminated polydimethylsiloxane/divinylbenzene/β-cyclodextrin coating by the Sol-Gel method to prepare coated direct inlet probe(CDIP).A direct sampling analysis method based on high resolution mass spectrometry was established by combining atmospheric pressure chemical ionization source with quadrupole-time-of-flight mass detector(QTOF).The coating was about 1 cm in length and 170 μm in thickness.Scanning electron microscopy(SEM)showed that the surface of the coating was smooth with a few hole,which had anti-pollution ability and could increase the extraction speed.CDIP can be applied to the rapid detection of polycyclic aromatic hydrocarbons in the seawater.The optimum corona current was 8000 μA,the desorption pressure was 5.0 bar,the desorption temperature was 250 ℃,and the equilibrium time is 15 min.The limit of detection of PAHs was 0.025-0.09 ng/m L.The linear range of was 0.5-50 ng/m L and R2 ≥0.9982.The recovery was 81%-109%,the relative standard deviation(RSD)was less than 20%,and the reproducibility between probes was less than 10%.The detection for single sample can be completed in 5 minutes,the lifespan was at least 50 times,and the extracted probe could be stable in at least 5 days.CDIP can be applied to the rapid detection of phthalates acid esters and alkylphenols in fish.The optimum desorption pressure was 2.0 bar and the shaking rate was 500 rpm.The optimum extraction temperature was 50 ℃.The optimum detection equilibrium time was 40 minutes.The multi-sample extraction mode can extract up to 12 samples at the same time,and the total analysis time was less than 10 minutes.The limit of detection was 0.01-40 ng/g.The linear range was from 0.3 to 15000 ng/g.R2≥ 0.9837.The RSD between day and day was less than 20%.According to the absorption value curve,the method is suitable for compounds with wide polarity and especially for substances of mid polarity.Carassius auratus was detected from three water areas and the content of pollutants was obtained.Principal component analysis(PCA)was used to distinguish Carassius auratus from different habitats according to the different content of pollutants in fish.CDIP can be used for rapid identification of cinnamon from different origins.Using electronic nose and static headspace-gas chromatography-mass spectrometry(GC-MS)can not distinguish the characteristic volatile substances of cinnamon.Headspace SPME-GC-MS combined with PCA analysis can be used to identify cinnamon from different origins.CDIP method can also be used to distinguish cinnamon from different origins,and the analysis time is shorter.In the future,VIP value of compounds can be obtained by PLS-DA,and the fingerprint compounds of cinnamon can be obtained.Finally,a direct sampling method based on high resolution mass spectrometry with fast analysis speed,high sensitivity,simple operation and good reproducibility has been established. |
