ATMOSPHERIC PRESSURE CHEMICAL IONIZATION (MPHARM,BPHARM ,MSC,BSC,P.ANALYSIS)

PRINCIPLE AND INSTRUMENTATION OF APCI

1. jjjAT Presented by : Souparnika T Ist M.Pharm Pharmaceutical Chemistry PRINCIPLE AND INSTRUMENTATION OF APCI (ATMOSPHERIC PRESSURE CHEMICAL IONIZATION)

2. What is mass spectroscopy Mass spectroscopy that charged particles passing through a magnetic field is deflected along circular path on a radius that is proportional to the mass to charge ratio M/Z. Principle A beam of electrons will be bombarded in the analyte compound and it will leads to removal of 1 electron from analyte. Due to removal of electron and molecules will be positively charged and known as molecular ion . 1

3. . M + Molecular ion (unstable) M 1 + , M 2 . M 1 . M 2 + M 1 + + M 2 + Stable ion Instrumentation of mass spectroscopy Sample inlet Ionization chamber Ion separator/ mass analyser Ion collector ,detector Vaccum system 2

4. Ionization chamber Volatile samples Electron impact ionization Chemical ionization GC inlets Non volatile sample Fast atom bambartment MALDI Electrospary ionization APCI 3

5. Atmospheric pressure chemical ionization (APCI) What is APCI It is a type of soft ionization technique ,which is based upon the mechanism of evaporaton. Actually it is a combination of chemical ionization and electrospray ionization with some deviation. Generally APCI is coupled with chromatographic instruments like HPLC. Analogous to chemical ionization For compounds with MW about 1,500 Da Produce monocharged ions It is similar to ESI 4

6. Figure no 1:APCI Diagram 5 PRINCIPLE AND INSTRUMENTATION OF APCI

7. S ample will be injected into the capillary supplied as a nebulizing gas, (It will helps to spray the sample and the analyte) Apart from this here to supply N 2 gas as a dissolvation gas It will convert in the form of vapour ( Analyte vapour and Solvent vapour) It will be analyse by corona discharge electrode, Corona discharge electrode will ionize the solvent vapour molecule just like a primary ion in chemical ionization 1 st step 2 nd step 6

8. Analyte and solvent vapour will pass through the corona discharge electrode The solvent will be ionized in the form of H ⁺ and Due to collision and ion molecule charge transfer between solvent and analyte takes place, it will produce MH ⁺ ions. A + S⁺ MH ⁺ + S⁻ (Positive ions) (Quasi molecular ion) ( M - - H ⁻ ) A⁺ + S (MH ) - + SH ⁺ (Negative ions) (also called as (M-1 ) - ) 3 rd step 7

9. Carbon Fiber Ionization Mass Spectrometry for the Analysis of Analytes in Vapour, Liquid, and Solid Phase In APCI using carbon fibre as a corona discharge ingredient. Figure no:2 carbon fibre ionization mass spectroscopy Eg . possibility of different chemical structure of aroma compound derived from the sesame oil = 23 type 8

10. APCI Consideration Solution chemistry parameters Less sensitive to chemistry effects than ESI –ion suppresion not so important. Best sensitivity at higher flow rates than ESI. Accommodates some non polar solvents not compatilble with ESI (hexane , CH 2 CI 2 Limitation for sample Thermally labile ,polar and high mwt compounds due to the vapourization process. Compounds of intermediates do not contain acidic or basic sites( eg . Hydrocarbons, steroids, alcohol, Ketons , esters) 9

11. APPLICATION APCI works well for small molecule that are moderately polar to non polar. APCI works well for sample that contain heteroatoms. Avoid sample that typically are charged in solution. Avoid samples that are very thermally unstable or photosensitive . Figure no:3 Mass spectra of fatty acid Figure no:4 mass spectra of fatty esters 10

12. Figure no:5 mass spectra of fatty amine Figure no:6 mass spectra of histamine Figure no:7 mass spectra of phenanthrene , and derivatives 11

13. Figure no:8 mass spectra of cinnamic deviatives 12

14. REFERENCE : Wu ML, Chen TY, Chen YC, Chen YC. Carbon fiber ionization mass spectrometry for the analysis of analytes in vapor , liquid, and solid phases. Analytical chemistry. 2017 Dec 19;89(24):13458-65. Martínez -Vargas BL, Díaz -Real JA, Reyes-Vidal Y, Rodríguez- López JL, Ortega-Borges R, Ortiz- Frade L. Competition between the reaction medium and nanostructured ZnO in the photocatalytic degradation of anthracene. Toward an optimal process for polycyclic aromatic hydrocarbons remediation. Química Nova. 2017;40:6-16 13

15. Ji B, Zhao Y, Zhang Q, Wang P, Guan J, Rong R, Yu Z. Simultaneous determination of cinnamaldehyde , cinnamic acid, and 2-methoxy cinnamic acid in rat whole blood after oral administration of volatile oil of Cinnamoni Ramulus by UHPLC-MS/MS: An application for a pharmacokinetic study. Journal of Chromatography B. 2015 Sep 15;1001:107-13. University of Bristol, High Performance Liquid Chromatography Mass Spectrometry (HPLC/MS ). 14

16. Agilent Technical Overview:  Making your LC method compatible with mass spectrometry,  Edgar Naegale , Waldbronn , Germany . Colizza K, Mahoney K E, et al., J. Am. Soc. Mass Spectrom . (2016) Updated 17th June 2014 by Paul Gates | University of Bristol, School of Chemistry, Cantock's Close, Bristol BS8 1TS, United Kingdom . Image from google. 15