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Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.
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Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

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Page 1: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Introduction to DART MS

Robert B. Cody

JEOL USA, Inc.

Page 2: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Outline

• Definition of terms

• DART operating principle

• TOF mass spectrometer overview

• The information we obtain

Page 3: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Definitions of MS terms and general concepts

Page 4: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

High Resolution Mass Spectrometry

• We will be using exact-mass measurements to to confirm knowns and to determine elemental compositions for unknowns

• Resolving power defines how well the mass spectrometer can separate close peaks (interferences)

• The elemental composition software gives us other information for each candidate composition (e.g. unsaturation)

Page 5: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Resolving Power

R = M / M

R = Resolving Power

M = m/z

M = difference in mass that can be separated

Page 6: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

R = M / MR = 5000m/z 500

M = Peak width at half-height = 0.1

Resolving Power Defined as: FWHM (Full width at half maximum)

0.1

Page 7: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

R = M / MR = 500

m/z 500 and 501 can be separated at a 10% Valley

M = 1

Resolving Power Defined as: 10% Valley Definition

501

500

Page 8: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Examples for C36H74 (m/z 506.579)

R = 500 (10% valley)

Separate m/z 500 from 501

R = 5000 (10% valley)

Separate m/z 500 from 500.1

Page 9: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Why the definition matters

R = 500 (10% valley) R = 500 (FWHM)

R = 5000 (FWHM)

Page 10: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Mass accuracy

• millimass units (0.001) or “mmu”

ppm = 106 * (M / M)

• parts-per-million (ppm)– “Resolution” (reciprocal of resolving power)

Note: ppm is a m/z – dependent value

Page 11: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Unsaturation (aka “rings and double bonds” aka “double bond equivalents”)

• Value is calculated from elemental composition• Indicates total rings, double bonds, triple bonds• Exact integer (e.g. “4.0”) or half-integer (“3.5”)

C6H6+.

D = 4.0

CH3 CH3

O H+

C3H7O+.

D = 0.5, add 0.5

CH3COO-

D = 1.5, subtract 0.5

H3O+

D = -0.5, add 0.5

Page 12: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopExamples of Even-electron ionsand Odd-electron ions

• Even-electron ions (half integer unsaturation) :Protonated molecule [M+H]+

Deprotonated molecule [M-H]-

Chloride adduct [M+Cl]-

Ammoniated molecule [M+NH4]+

Fragment F+

• Odd-electron ions (exact integer unsaturation) :Molecular radical cation M+.

Molecular radical anion M-.

Fragment F +.

Page 13: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

On-line Resources

• DART Users’ Google Newsgroup– http://groups.google.com/group/dart-mass-spectrometer-users?hl=en

• JEOL USA, Inc. Web Pages– http://www.jeolusa.com

• IonSense Web Page– http://www.ionsense.com

• Wikipedia article on DART– http://en.wikipedia.org/wiki/DART_ion_source

• Proton affinities, ionization energies (NIST)– http://webbook.nist.gov/chemistry/

Page 14: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

DART Basic Principles

See the JEOL News Article on theAccuTOF-DART product page on

www.jeolusa.com

Page 15: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

DART:“Direct Analysis in Real Time”

• Operational in Jan. 2003• Patent filed in April 2003• Public disclosure, Jan. 2005• Commercial product introduced March 2005• First open-air, ambient ion source for MS

1. Cody, R. B.; Laramee, J. A. “Method for atmospheric pressure ionization” US Patent Number 6,949,741 issued September 27, 2005.2. Laramee, J. A.; Cody, R. B. “Method for Atmospheric Pressure Analyte Ionization” US Patent Number 7,112,785 issued September 26, 2006.

Page 16: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Prototype DART sources

Original prototype DART source (mid-2002) Second DART prototype(Early 2003)

Page 17: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

The Whole Package:AccuTOF-DART™

Page 18: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Why DART?

• Fast and easy way to introduce samples• Minimal sample preparation for most samples• Can tolerate “dirty” or high-concentration

samples and without contamination• Fast fingerprinting of materials

Page 19: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Nothing comes without a price

• Chromatography/MS still has advantages over DART in detection limits, selectivity and sensitivity for certain samples

• Not useful for large biomolecules (no good for DNA analysis, proteins)

• DART does not ionize metals, minerals, etc.

Page 20: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

DART Schematic

Page 21: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Penning ionization

Sample ionized directly by energy transfer from metastables (M*)

Proton transfer (positive ions)

1. He* ionizes atmospheric water

2. Ionized water clusters transfer proton to sample

Electron capture (negative ions)

1. Penning electrons rapidly thermalized

2. Oxygen captures electrons

3. O2- ionizes sample

DART Source

DART Ionization

MS APIInterface

M*

Page 22: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Penning Ionization

• Metastable atoms or molecules react with analytes that posses ionization potentials less than the metastable energy,

M* + S S+. + M + electron

• The helium 23S state has 19.8 eV of internal energy and lasts up to 8 minutes in vacuum.

– Most molecules have ionization energies much lower than 19.8 eV

Page 23: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Proton Transfer

• Metastable atoms react with atmospheric water to produce ionized water clusters

• Dominant reaction mechanism when helium carrier used: He(23S) energy = 19.8 eV

• Huge reaction cross section: 100 A2

He(23S) + H2O H2O+• + He(11S) + electron

H2O+• + H2O H3O+ + OH•

H3O+ + nH2O [(H2O)n+1H]+

[(H2O)nH]+ + M MH+ + nH2O

Page 24: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Typical DART Low-Mass Background

0

20

40

60

80

100

Rel

. A

bu

nd

.

15 20 25 30 35 40 45 50 55

m/z

NH4+

H3O+

NO+

[(H2O)2+H]+

[(H2O)3+H]+

Normal DART Parameters

Page 25: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Negative Ion Formation

• Electrons produced by direct or surface Penning ionization are rapidly thermalized

• Thermal electrons react with atmospheric oxygen and water to produce ionized clusters

• Oxygen/water cluster ions react with analyte molecules to produce analyte ions

e-* + G e- + G*

e- + O2 O2-.

O2-. + S [S-H]- + OOH.

O2-. + S S-. + O2

O2-. + S [S+O2]-.* + G [S+O2]-. + G*

Page 26: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopTypical DART Negative-IonLow-Mass Background

20 40 60 80 100

m/z

Rel

. abu

ndan

ce [H2O3]-O2-

[HCO4]-

[HCO3]-

[H2O4]-

20 40 60 80 100

m/z

Rel

. abu

ndan

ce [H2O3]-O2-

[HCO4]-

[HCO3]-

[H2O4]-

Note the absence of nitrogen oxide ions that would be produced by electrical discharge in air. NO2

- and NO3

- are problematic for detection of nitro explosives and reduce anion detection sensitivity

Page 27: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Example

[M-H]-

0

50

100

Rel

. A

bu

nd

.

100 150

m/z

175.0232

0

50

100

Rel

. A

bu

nd

.

100 150

m/z

177.0410

[M+H]+

[M+H-2H2O]+

[M+H-H2O]+

Positive ions

Negative ions

Ascorbic acid, C6H8O6

127 130 133 136 139 142 145 148 151 154 157 160 163 166 169 1729

52

95

O

OH O

H O

O H

H O

Sampled directly from a melting point tube

Page 28: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Notes on the AccuTOF Design and Operation

See the JEOL News Article on theAccuTOF-LC product page on

www.jeolusa.com

Page 29: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Types of mass spectrometers

• Scanning: – magnetic sector, quadrupole and triple

quadrupole

• Trapped-ion: – Fourier transform, 3D ion trap, Orbitrap

– linear trap (used in triple quadupole MS)

• Time-of-flight• Hybrids

Page 30: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopDART can be fit on most mass spectrometer types

DART signals can be transient, so,

• scanning mass specs work best with selected ion monitoring or fast scanning

• Selected reaction monitoring on triple quadrupole MS is good for target compound quantitation.

• Ion traps work, but are not a good choice for quantitative analysis

• Time-of-flight is fastest MS for transient signals, and gives high-resolution data for the entire mass spectrum with no sensitivity loss.

Page 31: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Time of flight principle

Heavy ions moving slowly

L’Alpe D’Huezde

Spectrometrie de Masse

Light ions moving quickly DetectorIf everyone starts at the same time and has the same kinetic energy, lighter riders will move faster

Page 32: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

A more realistic TOF mass spectrometer

High voltage to accelerate ions

Ion detector

Ion source:Short burst of ions

Flight tube

Kinetic Energy = qE = mv2/2

Page 33: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

What if ions that have the same mass have slightly different energies?

• Reflectron: make the more energetic ions travel further

Page 34: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Reflectron Time of flight mass analyzer principle

MeLance

1. Fast riders miss the turn

Page 35: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopReflectron Time of flight mass analyzer principle

2. Fast riders turn around; have to travel further

Page 36: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Reflectron TOF

3. Fast riders start to catch up

Page 37: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Reflectron TOF

4. Fast riders catch up, will eventually pass

Focal point

Page 38: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Time-of-flight math• All ions fly with the same kinetic energy.

• Flight time is inversely proportional to the square root of the mass/charge ratio.

M

q

V

Ltof

VeqvmM u 2)(2

1

M: mass of ion [u] mu: Atom mass unit (1.6605 x 10-27 [kg/u])

v: flight speed of ion [m/s] q: charge number of ion

e: unit electric charge (1.602 x 10-19 [C]) V: Accelerating voltage [V]

Page 39: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

JMS-T100LC AccuTOFTM

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

Page 40: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

AccuTOFTM Ion Source

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

Page 41: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopOrthogonal ESI ion source and API interface

Nebulizer Gas

RP TMP

Desolvating Chamber

Orifice1Ring Lens

Orifice2Ion GuideDesolvating

Gas

LC Eluent

Page 42: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Ion Source and Atmospheric Pressure Ionization (API) Interface

• Orthogonal ESI– Minimize contamination into API interface

• Simple API interface– Robust, few parameters, minimal maintenance

• Off-axis skimmers and ring lens, bent ion guide– Keep contamination out of high-vacuum region

Page 43: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

AccuTOFTM Ion Transport

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

Page 44: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Ion transport region

• Strong acceleration of ions only occurs in high-vacuum region– Minimize CID and scattering

• Quadrupole RF ion guide focuses ions to a small spot size– Spatial focus for good resolution

– “High-pass” filter (ions greater than given m/z)

• Multi-function focusing and steering lenses– Beam should be perpendicular

Page 45: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

AccuTOFTM Analyzer

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

z

y

x

Page 46: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

AccuTOFTM Analyzer

• Two-step acceleration– Spatial focusing of ion beam

• Single reflectron– Energy focusing of ion beam in the x-direction– Minimize ion loss

• oa(Orthogonal-Acceleration)-TOF MS– Kinetic energy spread in y-direction has no effect

on resolution– The ions produced by the ESI ion source are

used efficiently.

z

y

x (reflectron)

(injection)

Page 47: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

• 1. Introduction of ion– Two kinds of ions are introduced at the same time.

Ion Source Low mass ionHigh mass ionMixture of both ions

Page 48: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

• 2. Turn on the pulser voltage– Mixture of ions at the start of flight

++++++

-

-

Ion Source

Page 49: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

Ion Source

• 3. Turn off the pulser voltage– continuing flight - mass separation

Page 50: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

Ion Source

• 4. Continuing flight – New ions are introduced in the ion acceleration part.

Page 51: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

Ion Source

• 5. Low mass ion reaches detector– The ion acceleration region is filled with the new ions.

Page 52: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

Ion Source

• 6. High mass ion reaches detector

Page 53: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Flight cycle of oa-TOF MS

Ion Source

• 7. The detection of all ions is completed

Page 54: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

AccuTOFTM Detection system

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

Page 55: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Detector

① Micro-channel plate (MCP) 40mmφ Dual MCP

② Anode Combined with high voltage capacitor

Patent pending+

e-

in the vacuum

in the atmosphere

Dual MCP

Anode

To impedance converter

Page 56: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

MCP• Diameter : 40mm• Thickness : 0.6mm• I.D. of channel : 10μm• Gap of each channel : 12μm

Page 57: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Data collection system for oa-TOF MS

• High time resolution– m/z 609, R=6,000 → Peak width: 3.5ns

• Continuous data collection– High duty cycle

• Real-time accumulation of mass spectrum

- Requirements -

Page 58: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Data collection system for oa-TOF MS

• TDC– Super-high speed

digital stop watch

– Measures the arrival time of ions

– A premise is that there are a few ions

• Each ion arrives separately.

• Ion counting detection: signal is 0 or 1.

• Continuous Averager– A signal from the

detector is converted digital value by a high-speed ADC (Analog-to-Digital Converter).

– Spectrum can be accumulated continuously in real time.

Page 59: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopTDC (Time-to-Digital Converter)

High Voltage

Pulser

DiscriminatorAmp

Start Input

Stop Input

59us

Time-to-Digital

Converter

No. TOF [us] 1 29.4235 2 46.2890 ....

No. of Ions Detected in a Cycle

Histogram Memory

To Data System

Page 60: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopSimulation of spectrum accumulation by TDC

Output from Amplifier : Cycle 1

0

5

10

15

20

1 5 9 13 17 21 25 29 33 37 41 45

mV

Histgram memory : Cycle 1

0

1

2

3

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46

No.

of

Ions

Page 61: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopSimulation of spectrum accumulation by TDC

Output from Amplifier : Cycle 2

0

5

10

15

20

1 5 9 13 17 21 25 29 33 37 41 45

mV

Histgram memory : Cycle 2

0

1

2

3

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46

No.

of

Ions

Page 62: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 3

05

101520

1 5 9 13 17 21 25 29 33 37 41 45

mV

Histgram memory : Cycle 3

0

1

2

3

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46

No.

of

Ions

Simulation of spectrum accumulation by TDC

Page 63: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 4

05

101520

1 5 9 13 17 21 25 29 33 37 41 45

mV

Histgram memory : Cycle 4

0

1

2

3

1 5 9 13 17 21 25 29 33 37 41 45

No.

of

Ions

The ion which had about two times higher intensity was detected.

It is counted only once (not twice) with TDC.

Simulation of spectrum accumulation by TDC

Page 64: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 5

0

5

10

15

201 5 9 13 17 21 25 29 33 37 41 45

mV

Histgram memory : Cycle 5

0

1

2

3

1 5 9 13 17 21 25 29 33 37 41 45

No.

of

Ions

Two ions detected in succession!

The second ion can't be counted during dead time.

Simulation of spectrum accumulation by TDC

Page 65: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopResult of spectrum accumulation by TDC

• The ratio of the peak intensity isn't correct.

• A high intense peak shifts to low mass side.

Histgram memory : Cycle 5

0

1

2

3

1 5 9 13 17 21 25 29 33 37 41 45

No.

of

Ions

model spectrum :

05

10152025

1 5 9 13 17 21 25 29 33 37 41 45

No.

of

Ions

Page 66: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopContinuous Averager

High Voltage

Pulser

Amp

59us

Intensity1528 ....

No. of Data Points on a Spectrum

(up to 256K points)

Summing Memory

To Data System

ADC

(8bit)

Timing Control Circuit

Adder

Continuous Averager

Page 67: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopSimulation of spectrum accumulation by continuous averager

Output from Amplifier : Cycle 1

0

5

10

15

20

1 5 9 13 17 21 25 29 33 37 41 45

mV

Cycle 1

01020304050

1 5 9 13

17

21

25

29

33

37

41

45

mV

Page 68: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 2

0

5

10

15

20

1 5 9 13 17 21 25 29 33 37 41 45

mV

Cycle 2

01020304050

1 5 9 13 17 21 25 29 33 37 41 45

mV

Simulation of spectrum accumulation by continuous averager

Page 69: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 3

05

101520

1 5 9 13 17 21 25 29 33 37 41 45

mV

Cycle 3

01020304050

1 5 9 13 17 21 25 29 33 37 41 45

mV

Simulation of spectrum accumulation by continuous averager

Page 70: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 4

05

101520

1 5 9 13 17 21 25 29 33 37 41 45

mV

Cycle 4

01020304050

1 5 9 13 17 21 25 29 33 37 41 45

mV

Simulation of spectrum accumulation by continuous averager

Page 71: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Output from Amplifier : Cycle 5

05

101520

1 5 9 13 17 21 25 29 33 37 41 45

mV

Cycle 5

01020304050

1 5 9 13 17 21 25 29 33 37 41 45

mV

Simulation of spectrum accumulation by continuous averager

Page 72: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

• The ratio of the peak intensity is correct.

• There is no shift of the ion peak.

model spectrum :

05

10152025

1 5 9 13 17 21 25 29 33 37 41 45

No.

of

Ions

Cycle 5

01020304050

1 5 9 13 17 21 25 29 33 37 41 45

mV

Result of spectrum accumulation by continuous averager

Page 73: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Specifications

• Mass resolution : 6,000– FWHM, Reserpine m/z 609

• Sensitivity : Reserpine 10pg S/N>10– LC-ESI [ Flow rate: 0.2mL/min ]– Mass chromatogram of m/z 609, RMS

• Mass accuracy : 5ppm RMS– With internal reference– (Typically better than that!)

Page 74: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopOnly 3 analyzer parameters are critical for routine DART analysis

TMP2

RP

TMP1

RP

Ion SourceIon

Transportation Analyser

Detection system

To the data collection

system

1 2

3

1: Orifice 1 2: “Peaks voltage”3. Multiplier V

Page 75: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

The 3 important parameters

• 1: Orifice 1: Typically 20V– Increase O1 to increase fragmentation

• 2: “Peaks voltage” (RF ion guide voltage)– Divide by 10 to estimate lowest detected m/z

• 3. Multiplier V: Typically 2200V to 2600V– Increase multiplier to increase signal (and

noise)

Page 76: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopInformation from the TOF mass spectrum

• Exact mass + isotope peaks: elemental composition

• Fragmentation: distinguish isomers• “Fingerprint” pattern: material ID• Ion abundance: quantitative analysis• Other experiments: H/D exchange,

derivatization, etc.

Page 77: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Example: DART mass spectrum of a leaf

0

20

40

60

80

100

Rel

. A

bu

nd

.

100 150 200 250 300 350

m/z

290.174304.154

What is this?

Page 78: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

We can treat this as an unknown

Page 79: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Elemental compositions

Elemental Composition Program

MeasuredExact Mass

Constraints

Candidate compositions

Ranked compositions

Isotope pattern matching

Page 80: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopWe have a composition. Now what?

m/z 304.1548 is C17H22NO4

CocaineScopolamine

174 184 194 204 214 224 234 244 254 264 274 28417

57

97

N

OO

O

O H

Fragments at m/z 138, 156

202 212 222 232 242 252 262 272 282 29213

56

99

N

H

H O

O

O

O

Fragments at m/z 182, 82

182

138

C10H16NO2+

C8H12NO+

156C8H14NO2

+

Page 81: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Control fragmentationwith Orifice 1 and Ring Lens potentials

Nebulizer Gas

RP TMP

Desolvating Chamber

Orifice1Ring Lens

Orifice2Ion GuideDesolvating

Gas

LC Eluent

API interface change potentials to induce fragmentation

Page 82: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

0

20

40

60

80

100

Rel

. A

bu

nd

.

100 150 200 250 300

m/z

Fragment spectrum increase cone voltage from 20 V to 60 V

290.174

304.154156.099138.089

C8H12NO+ C8H14NO2+

Scopolamine

Atropine

C8H14N+

Scopolamine

Page 83: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition WorkshopFor comparison, m/z 305.1548 fragments from a dollar bill

0

20

40

60

80

100

Rel

. A

bu

nd

.

100 150 200 250 300 350

m/z

82.065

182.118

Cocaine

C5H8N+

C10H16NO2+

C17H22NO4+

Page 84: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshopor…we can search for candidates from a list of target compounds.

SearchFromList Program

Components in asmokeless powder

Page 85: Technology Transition Workshop Introduction to DART MS Robert B. Cody JEOL USA, Inc.

Technology Transition Workshop

Whew…!

Confused?

It’ll make more sense when you see it in the lab.