3500
1000
3000
acetaminophen
UV C14 800
2500
benzoic acid
600
mAU
2000
tyrosine
1500 400 1000
500
200
0 0 100 200 300 400
Time [sec]
BEAMS Lab
14C counts
Cross-sectional View of Interface (v. 1.0)
Combustion interface v. 2.0 1st Detection of 14C 1st SBIR grant to NSI 2nd Patent issues Combustion interface v. 1.0 Development of GC interface
1999 1994 2000 2002
Sample collection: Blood: Urine: Feces: 1, 2, 5, 8, 24 and 48 hours post dose 0-8, 8-24 and 24-48 hours post dose 0-8, 8-24 and 24-48 hours post dose
BEAMS Lab
Comparison of Methods Conventional AMS
Collect Fractions Chromatographed sample (LC, GC, CE effluent)
BEAMS Lab
Bulk sample (tissue, blood, urine, …) Oxidation to CO2 or H2O Online generation of CO2 or H2
Combustion interface v. 2.0 1st Detection of 14C 1st SBIR grant to NSI 2nd Patent issues Combustion interface v. 1.0 Development of GC interface
1999 1994 2000 2002
BEAMS Lab
Quantitative Analysis: Comparison of Instrument Types
Graphite
Method of quantitation Limits of quantitation Measurement period Sample throughput Isotope ratio:
2004 2005
Laser-induced combustion proof-of-principle Patent apps. filed
Gas ionization detector 1st Patent issues
BEAMS Lab
A Brief History of AMS at MIT
1400
0.21 dpm
Carbon-14 Count Rate (counts/sec)
1200
1000
0.14 dpm
800
0.084 dpm 0.042 dpm
600
400
0.014 dpm
200
0
0 1 2 3 4 5 6 7 8 9 10
Time (minute)
BEAMS Lab
HPLC-AMS with Laser-induced Combustion Interface
Reduction to Graphite or Titanium Hydride
Continuous-flow, Single Target, Multi-sample Ion Source
Solid Cathode, Multiple Target Ion Source
Higher Throughput
He in CuO bed Alumina cup
He + CO2 out
BEAMS Lab
Combustion Interface (v. 2.0) Sample Holder
BEAMS Lab
1000
1250
1500
1750
2000
2250
Counts
250
500
750
0 45.250 (9020.408) 167.250 (163.396) 200 386.750 (139.953) 400 480.000 (215.865) 580.500 (239.450) 600 688.000 (461.236) 800 793.250 (553.789) 1000 1200 1236.250 (9728.563) 1344.750 (10386.208) 1400 1464.750 (42402.176) 1021.607 (3263.763) 1126.547 (2691.743) 900.500 (15643.945) *C14 File (C:\DOCUME~1\ROSALI~1\MYDOCU~1\AMS\DATA\2005\ANALYSIS\PFIZER\CALIBR~1\FEB23\0223R010.CSV)
Plasma Clearance: Unbound APAP + Metabolites
200
APAP equivalents (µg/mL)
100 50
10 µCi dose by LSC 10 nCi dose by AMS
10 5
1
0
5
10
15
20
25
Time after dose (hours)
BEAMS Lab
APAP Urinary metabolites
100
Percent of total metabolites
10 µCi dose by LSC 10 nCi dose by AMS 80
60
40
20
0
Glucuronide Sulfate
APAP Mercapturate
BEAMS Lab
Validate analytical methods for low-level isotope detection at therapeutic doses Rat/Sprague-Dawley/males/250-300 g/ 2 Groups of N=4 All: Group 1: Group 2: 150 mg/kg + 10 µCi [14C]-Acetaminophen + 10 nCi [14C]-Acetaminopation Curves for Whole Plasma
60
50
Peak area ratio
40
30
20
10
3-1 3-2 (1) 3-2 (2) 0 20 40 60 80 100 120
0
Actual 14C concentration (dpm/mL)
BEAMS Lab
Laser-induced heating of CuO causes sample combustion Resulting CO2 transported to AMS ion source
BEAMS Lab
Detection of [14C]-Acetaminophen with Laser-induced Sample Combustion
High Sample Throughput Approaches to Accelerator Mass Spectrometry
P. L. Skipper, R. G. Liberman, J. Flarakos, and S. R. Tannenbaum BEAMS Lab Biological Engineering Division Massachusetts Institute of Technology
1999 1994 2000 2002
2004 2005
Laser-induced combustion proof-of-principle Patent apps. filed
Gas ionization detector 1st Patent issues
BEAMS Lab
A Brief History of AMS at MIT
10 – 1 M 100 zmol Duration of CO2 pulse: 1 – 30 sec > 1 per min
BEAMS Lab
A Brief History of AMS at MIT
Combustion interface v. 2.0 1st Detection of 14C 1st SBIR grant to NSI 2nd Patent issues Combustion interface v. 1.0 Development of GC interface
– DNA damage
• Oxidants • Carcinogenic compounds
• Future directions
– GC-AMS: dual isotope measurements – Tritium AMS
BEAMS Lab
BEAMS Lab
BEAMS Lab
Sample Preparation and Analysis:
sample 14C sample 12C
MIT
Peak area ratio:
sample 14C ext.std. 14C
10-3 – 10-2 M 100 zmol To statistical precision: 1 sec – 30 min Limited by sample prep or