Miniaturization in the Future of Mass Spectrometry

LECTURE 7

Jack Henion, Ph.D.

Emeritus Professor, Analytical Toxicology

Cornell University

Ithaca, NY 14850 Lecture 7, Page 1

Contents

• Commercial Systems To-Date:

–Purdue University “Mini 11”

–Torion

–Microsaic

–Advion expression

Lecture 7, Page 2

Differentiation Between Small Mass Spectrometers

• Electron ionization (EI)

– Requires much less pumping and is easier to build

• May be pumped with inexpensive diaphragm pumps

• Several are on the market

• Atmospheric Pressure Ionization (API)

– Requires much more pumping

• Needs more costly, heavier pumps such as turbo molecular pumps

• Limited commercial availability currently

Lecture 7, Page 3

Purdue University Mini 11 Mass Spectrometer

Has an API Inlet Lecture 7, Page 4

ESI of Cocaine from Purdue Mini 11

Lecture 7, Page 5

Torion Portable GC/MS (this system is not equipped for LC/MS applications)

Has GC/MS Inlet with EI Lecture 7, Page 6

Smaller – Lighter – Faster – More Capability in your HANDS

7 Lecture 7, Page 7

• Dimensions: 38 cm x 39 cm x 23 cm • Weight: <14.5 kg or 32 lbs (including battery) • Power: Peak ~120 W; Average ~ 60 W • Sample introduction: SPME or direct liquid • GC: MXT-5, 5 m x 0.1 mm x 0.4 mm • Temperature programmable GC • Electronic pressure control • Ion trap: Toroidal ion trap MS • Electron ionization: Internal • Vacuum: Turbo molecular/diaphragm pump • Ion trap heater: 150°C – 180°C • Mass range: 45 to 500 da. • Resolution: Amplitude scanning 0.43 at m/z 134 (n-butylbenzene) 0.53 at m/z 284/286 (hexachlorobenzene)

TRIDION™-9 Specifications

15”

15.5” No Handle

17.5” With Handle

9”

Lecture 7, Page 8

Who Needs Portability?

• Chemical/petrochemical • Environmental • Food/flavor/fragrance • Government • Universities • Safety and hygiene • First response/hazmat • What about clinical? • What about bedside or point-of-care GC/MS?

Lecture 7, Page 9

Lammert et al., Int. J. Mass Spectrom. 2001, 212, 25

Toroidal Ion Trap MS

Miniature trap ro = 2 mm

Trapping Vmax = ~ 2 kVp-p

Conventional size trap ro = 1 cm

Trapping Vmax = ~ 16 kVp-p

Lecture 7, Page 10

171 175

173

~1 s

TRIDION-9 Mass Analyzer

• Resolution < 1 amu FWHM across mass range

• Scan speed ~10 scans/s

11 Lecture 7, Page 11

Miniaturizing the GC

Conventional Laboratory GC TRIDION™-9 GC

GC column

Injection port

Cooling fan Electronics

Lecture 7, Page 12

Easy-to-Use Software

• On-board and computer-based software

• Button or touch screen instrument operation

• Simple GUI interface - results are clear and concise

• Automated target compound identification

Lecture 7, Page 13

1

Peak Identifications

1. Benzene

2. Toluene

2

Gasoline in Water

Sample:

Concentration:

Gasoline in water, benzene

39 ppb

SPME: PDMS/CAR

Sampling: Headspace

Duration: 15 min w/ stirring

Temperature: Ambient

Lecture 7, Page 14