Mass Spectrometry Of Complex Samples Based On The Tube Tip Paper Spray Source

As one of the most effective analytical methods,mass spectrometry（MS）has the advantages of high sensitivity,strong specificity,and can provide information about molecular weight and chemical structure of target analytes,and has been widely used in many fields.In order to overcome the defect that complicated sample processing is required before quality spectrum analysis of complex samples.In 2004,atmospheric pressure ionization source technology is proposed by Cooks.This method can directly conduct mass spectrum analysis of target analytes in complex samples under normal temperature and pressure conditions.This technique greatly improves the efficiency of sample analysis and reduces the cost of analysis.Paper spray ionization（PSI）is a promising atmospheric ionization source technology.In the process of sample analysis,triangular paper matrix is used as the sample carrier and spray matrix.High pressure and spray solvent are applied to elution target compounds from the surface of paper matrix and generate charged ions.Although this method has been widely used in the analysis of target compounds in a variety of complex substrates,there are two problems in this technique:（i）Low desorption efficiency of target compounds;（ii）Poor portability.To address these problems,this Paper develops an in-tube tip paper spray ionization source（also known as Portable paper-based Electrospray Ionization,PPESI）technique,the ionization source combines the simple and rapid paper spray ionization source and the unique adsorption-desorption characteristics of the adsorbent,which can effectively remove the matrix interference of the sample and realize the highly sensitive analysis of the target compounds in complex samples.At the same time,it can effectively inhibit the solvent volatilization during the spray process and prolong the analysis time.Mainly carried out the following work:（1）This paper developed a portable paper-based electrospray ionization source,which is the triangular paper matrix and adsorbent into the modified pipette tip.And it allows direct mass spectrometry of target compounds in complex samples.The influence of various experimental parameters such as paper matrix,adsorbent and spray solvent on the analysis results was systematically investigated.The adsorbent can remove the matrix interference in complex samples,the pipette gun head can prevent the spray solvent from volatilization,improve the analytical sensitivity and spray time of PPESI-MS.The adsorbent can remove the matrix interference in complex samples,the pipette gun head can prevent the spray solvent from volatilization,improve the analytical sensitivity and spray time of PPESI-MS.By contrast to other related sources（pipette tip electrospray ionization source,paper spray ionization source,paper-capillary electrospray ionization source,and in-tube paper spray ionization source）,the analytical sensitivity and the spray duration of PPESI in tandem with MS have been improved by a factor of 2.8～32.3 and 2.0～13.3.（2）Different adsorbents had significant effects on the performance of portable paper-based electrospray ionization source analysis,and by mass spectrometry of blood samples containing favorable peridone drug compounds,the signal intensity showed a trend of Ti O₂<Mg O<Al₂O₃<Zr O₂<Si O₂<Zn O.Then the adsorption-desorption properties of various drug compounds were further investigated,and the change trend was consistent with the results of MS analysis.Through spray ionization experiments by loading methylene blue or Congo red dye into microstraws filled with different adsorbents,the results showed that the addition of Zn O adsorbent formed a small size and dark color compared to the other five adsorbents.Finally,it is proved that Zn O adsorbent is not easy to adsorb drug compounds and it is easy to desorate from the drug compounds,and the spray flow distribution is concentrated,so that the sensitivity of MS analysis is improved.（3）Portable paper-based Electrospray Ionization coupled to a mass spectrometer is used to quantitative analysis of risperidone drug compounds in biological samples（blood,serum,urine）.The results showed a linear range of 0.01～1000 ng m L^-1,linear correlation coefficient greater than 0.999,so the linear relationship is good.And the detection limit（LODs）and limit of quantification（LOQs）as low as 2～3 pg m L^-1and 5～11 pg m L^-1.Respectively,the relative standard deviation（RSD）is 2.0%～10.4%.This method has high accuracy and precision,and can be applied to the detection of various therapeutic drugs and pesticide residues in complex biological samples（e.g.,whole blood,serum and urine）and food samples（e.g.,milk and orange juice）.