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 .
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3. .M+ Molecular ion (unstable)
M1
+
, M
2
. M1
. M2
+
M1
+ + M2
+ Stable ion
Instrumentation of mass spectroscopy
1. Sample inlet
2. Ionization chamber
3. Ion separator/ mass analyser
4. Ion collector ,detector
5. Vaccum system
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4. Ionization chamber
Volatile samples
1. Electron impact
ionization
2. Chemical ionization
3. GC inlets
Non volatile sample
1. Fast atom
bambartment
2. MALDI
3. Electrospary
ionization
4. APCI
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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
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6. Figure no 1:APCI Diagram
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PRINCIPLE AND INSTRUMENTATION OF APCI

7. Sample 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 N2 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
1st step
2nd
step
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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)- )
3rd
step
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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
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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 , CH2CI2
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)
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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
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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
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13. Figure no:8 mass spectra of cinnamic deviatives
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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
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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).
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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.
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