DART(direct analysis in real time)-mass spectrometry - a new and sensitive ion source for mass spectrometry existing in many fields of analysis

1. B . Keerthana,
B.Pharm,
s.p.s.p Slide 1

2. Contents:
• Introduction
• Basic principle of Mass spectrometry
• Ionization
• Ion sources
• DART ion source
• DART ion application
• Mass spectrometry analyzers and detectors
Slide 2

3. Introduction of Mass
spectrometry
• MASS SPECTROMETRY:
Mass spectrometry is an instrumental technique in which
sample is converted to rapidly moving positive ions by
electron bombardment and charged particles are separated
according to their masses.
• MASS SPECTRUM:
Mass spectrum is a plot relative abundance against the ratio of
mass/charge(m/e).
Slide 3

4. Simple mass spectrometry
Slide 4

5. Organic molecules are bombarded with electrons
Converted into high energetic positively charged ions(molecular ions or parent
ions)
• Further break up into smaller ions(fragment ions or daughter ions)
• The formed ions are separated by deflection in magnetic field according to their mass and charge.
MASS SPECTRUM
slide5
Basic principle:

6. Modern Mass spectrometry
 Inlet system
 Ion sources
 Mass analysers
 Ion detectors
 Vacuum system
Slide 6

7. Instrumentation of mass spectrometry
Slide 7

8. Ionization sources:
 Chemical Ionization (CI)
 Atmospheric Pressure chemical ionization(APCI)
 Electron Impact (EI)
 Electrospray Ionization(ESI)
 Fast Atom Bombardment (FAB)
 Field Desorption/Field Ionization (FD/FI)
 Matrix Assisted Laser Desorption Ionization(MALDI)
 Thermo spray Ionization (TI)
 Direct analysis in real time(DART) Slide 8

9. Electron ionization:
• Side view of EI • Ion formation reaction occur in EI
Slide 9

10. Chemical Ionisation (CI)
 The ion formation reactions that can occur during methane CI.
Slide 10

11. Electrospray ionisation (ESI):
• An ESI source
Slide 11

12. • The mechanism of ion formation in ESI.
Slide 12

13. Atmospheric Pressure Chemical Ionisation (APCI):
 detailed view of the mechanism of APCI.
Slide 13

14. Fast atom bombardment(fab)& liquid
secondary ion mass spectrometry(lSIMS):
 the mechanism of fast particle beam ionisation mass spectrometry (FAB and LSIMS)
Slide 14

15. Matrix-assisted Laser Desorption/Ionisation
(MALDI)
 diagram of the mechanism of MALDI.
Slide 15

16. Introduction:
The new ion source reported herein over-comes these limitations.
The new technique, referred to as Direct Analysis in Real Time (DART tm), has been coupled to the AccuTOFLCtm
atmospheric pressure ionization mass spectrometer to permit high-resolution, exact mass measurements of gases, liquids,
and solids.
 DART successfully sampled hundreds of chemicals, including chemical agents and their signatures, pharmaceutics,
metabolites, pesticides and environmentally significant compounds etc.,
The composition of drug capsules and tablets was directly analyzed.
Slide 16
DART IONSOURCE ( DIRECT ANALYSIS IN
REAL TIME ) :

17. Slide 17
Dart ion source-mass
spectrometry:

18. Background and Principle of Operation:
 The discovery that DART could be used for positive-ion and negative-ion non-contact detection of materials on surfaces, as
well as for detection of gases and liquids.
 DART is based on the atmospheric pressure interactions of long-lived electronic excited-state atoms or vibronic excited-state
molecules with the sample and atmospheric gases.
 o The DART ion source is shown. A gas (typically helium or nitrogen) flows through a chamber where an electrical discharge
produces ions, electrons, and excited-state (metastable) atoms and molecules.
Slide 18

19. Principle of DART Ionization:
DART ionization is based on the interaction between excited state atoms or molecules, and
atmospheric gas and/or analytes.
 Plasma is generated by glow discharge from the needle electrode in a helium gas
stream. The plasma includes ions, electrons, and excited state (metastable) atoms or
molecules.
 The majority of charged particles are eliminated by the grounded
electrode and the excited state neutral species are expelled to the atmosphere.
The gas stream can be heated by the gas heater to help analytes vaporization or desorption
from the substrate surface.
Slide 19

20.  Minimal sample preparation;
 Sample maintenance under ambient conditions
 Outside the vacuum system;
 Rapid
 Sensitive
 High‐throughput analysis;
 The ability for in‐situ detection.
 Gentle ionization methods.
 Used for both organic and biological.
 Compounds, polar and non‐polar molecules Slide 20

21. Dart applications:
 Forensics
 Pharmaceutics
 food chemistry
 biological samples
 chemical analysis
 fragrance industry
 DART has been used for analysis of explosives ,drugs , inks , sexual assault evidence , and of synthetic
cannabinoids in herbal samples.
Slide 21

22. Mass Analyzers:
 quadrupoles
 Time-of-Flight (TOF)
 magnetic sectors
 Fourier transform and
 quadrupole ion traps.
Mass detectors:
 Electron multiplier
 Faraday cup
 Scintillator ('Daly' detector). Slide 22

23. fields that use mass spectrometry:
 Pharmaceutical sciences
 Proteomics
 Drug discovery
 Clinical testing
 Genomics
 Environmental sciences
 Geology etc.,
Slide 23
Applications of mass spectrometer:

24. [1]. https://masspec.scripps.edu/.
[2].Merriam-Webster dictionary, Medical dictionary by FARLAX, https://en.Wikipedia.org/.
[3]. Modern Mass Spectroscopy, pp. 1-302, 225. Springer-Verlag, Berlin, 2003.
[4]. MacMillan Group Meeting 2005 Sandra Lee.
[5]. http://simons.com/.
[6].RAPID COMM MASS SPECTROM,vol-II,2-16(1997),
[7].JEOL USA,Inc. EAI Corporation, GEO Centers Inc. Edgewood chemical
Biological center.
[8].https://www.jeolusa.com/ms/ms prodsaccutof_dart.html.
[9].Eid Alsbou (2010), MEMORIAL UNIVERSITY.
[10]. Witt & Bowers: JACS 2000,122, 3458.
[11]. J.L. Jimenez – Fall 2007 University of Colorado-Boulder.
Slide 24
References: