Canadian Bioinformacs Workshops · Liquid Chromatography - HPLC • Developed in 1970’s • Uses...

5/12/16

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CanadianBioinforma1csWorkshops

www.bioinforma1cs.ca

2 Module #: Title of Module

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Module1Introduc.ontoMetabolomics

DavidWishart

Module1 bioinformatics.ca

LearningObjec.ves

•  Todefinemetabolomicsandthesizeofthemetabolome(s)

•  Toappreciatetheimportanceandpoten.alapplica.onsofmetabolomics

•  Tounderstandtheopera.onalprinciplesofkeymetabolomicstechnologies(LC,GC,MSandNMR)

•  Tounderstandthedifferencebetweentargetedanduntargetedmetabolomics

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Schedule

Day 1 Day 2Thursday May 26 Friday May 27

8:00 Registration & Breakfast Breakfast

Welcome (Ann Meyer)

10:30 Coffee Break Coffee Break

12:30 Lunch - on your own Lunch - on your own

1:30 Module 2 Lab: Compound ID & Quantification

Module 5 Lab: Metabolomic Data Analysis using MetaboAnalyst 3.0

3:00 Coffee Break Coffee Break

3:30 Module 3 Lecture: Databases for Chemical, Spectral and Biological Data Module 5 Lab: Continued

Module 6: Future of MetabolomicsSurvey & Closing Remarks5:30 (Optional) Compound ID until 8pm

CANADIAN BIOINFORMATICS WORKSHOPSInformatics and Statistics for Metabolomics

Module 1: Introduction to Metabolomics (David Wishart)

Module 5: MetaboAnalyst(David Wishart and Jeff Xia)

Module 4: Backgrounder in Statistics (Jeff Xia)8:30

11:00 Module 2: Metabolite Identification


The Pyramid of Life

Genome

Proteome

Metabolome

Metabolomics Proteomics Genomics En

viro

nmen

tal I

nflu

ence

Phys

iolo

gica

l Inf

luen

ce

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What is Metabolomics?

•  Genomics - A field of life science research that uses High Throughput (HT) technologies to identify and/or characterize all the genes in a given cell, tissue or organism (i.e. the genome).

•  Metabolomics - A field of life science research that uses High Throughput (HT) technologies to identify and/or characterize all the small molecules or metabolites in a given cell, tissue or organism (i.e. the metabolome).


What is a Metabolite?

•  Any organic molecule detectable in the body with a MW < 1500 Da

•  Includes peptides, oligonucleotides, sugars, nucelosides, organic acids, ketones, aldehydes, amines, amino acids, lipids, steroids, alkaloids, foods, food additives, toxins, pollutants, drugs and drug metabolites

•  Includes human & microbial products •  Concentration > detectable (1 pM)

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What is a Metabolome?

•  The complete collection of small molecule metabolites in a cell, organ, tissue or organism

•  Includes endogenous and exogenous molecules as well as transient or even theoretical molecules

•  Defined by the detection technology •  Metabolome size is always ill-defined


Different Metabolomes

300,000 Chemicals

100,000 Chemicals

60,000 Chemicals

All Mammals All Microbes All Plants

The Pyramid of Life

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Human Metabolomes (2015)

Endogenous metabolites

Drugs

Food additives/Phytochemicals

Drug metabolites

Toxins/Env. Chemicals 3670 (T3DB) 1240 (DrugBank) 28500 (FooDB) 1550 (DrugBank) 19700 (HMDB)

M mM µM nM pM fM


Theoretical Human Metabolomes

M mM µM nM pM fM

Secondary endogenous metabolites

Secondary food metabolites

Secondary drug metabolites

Lipids/Lipid derivatives 100,000 (Lipidome) 10,000 (Drug metabolome) 100,000 (Food metabolome) 10,000 (Secondome)

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Why is Metabolomics Important?


Small Molecules Count…

•  >95% of all diagnostic clinical assays test for small molecules

•  89% of all known drugs are small molecules

•  50% of all drugs are derived from pre-existing metabolites

•  30% of identified genetic disorders involve diseases of small molecule metabolism

•  Small molecules serve as cofactors and signaling molecules to 1000’s of proteins

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Metabolites Are the Canaries of the Genome

A single base change can lead to a 10,000X change in metabolite levels


Metabolomics is More Time Sensitive Than Other “Omics”

Metabolomics

Proteomics

Genomics

Res

pons

e R

espo

nse

Res

pons

e

Time

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Metabolism is “Understood”


The Metabolome is Connected to all other “Omes”

Genome

Proteome

Meta bolome

The Pyramid of Life

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The Metabolome is Connected to All Other “Omes”

•  Small molecules (i.e. AMP, CMP, GMP, TMP) are the primary constituents of the genome & transcriptome

•  Small molecules (i.e. the 20 amino acids) are the primary constituents of the proteome

•  Small molecules (i.e. lipids) give cells their shape, form, integrity and structure

•  Small molecules (sugars, lipids, AAs, ATP) are the source of all cellular energy

•  Small molecules serve as cofactors and signaling molecules for both the proteome and the genome

•  The genome & proteome largely evolved to catalyze the chemistry of small molecules


Metabolomics Enables Systems Biology

Genomics

Proteomics

Meta bolomics

Systems Biology

Bioinformatics

Cheminformatics

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Metabolomics Applications

•  Genetic Disease Tests •  Nutritional Analysis •  Clinical Blood Analysis •  Clinical Urinalysis •  Cholesterol Testing •  Drug Compliance •  Transplant Monitoring •  MRS and CS imaging

•  Toxicology Testing •  Clinical Trial Testing •  Fermentation Monitoring •  Food & Beverage Tests •  Nutraceutical Analysis •  Drug Phenotyping •  Water Quality Testing •  Petrochemical Analysis


Metabolomics Methods

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Metabolomics Workflow

1234567ppm

Biological or Tissue Samples Extraction Biofluids or Extracts

Chemical Analysis Data Analysis


Comparing “Omics” Coverage

22,000 Genes

5000 Proteins

200

Chemicals

Metabolomics Proteomics Genomics C

ompl

eten

ess

The Pyramid of Life

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Why Metabolomics is Difficult

4 Bases

20 Amino acids

2x105

Chemicals

Metabolomics Proteomics Genomics C

hem

ical

Div

ersi

ty

The Pyramid of Life


Metabolomics Technologies

•  UPLC, HPLC •  CE/microfluidics •  LC-MS •  FT-MS •  QqQ-MS •  NMR spectroscopy •  X-ray crystallography •  GC-MS •  FTIR

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Chromatography


Chromatography •  The separation of components in a

mixture that involves passing the mixture dissolved in a "mobile phase" through a stationary phase, which separates the analyte to be measured from other molecules in the mixture based on differential partitioning between the mobile and stationary phases

•  Column, thin layer, liquid, gas, affinity, ion exchange, size exclusion, reverse phase, normal phase, gravity, high pressure

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High Pressure (Performance) Liquid Chromatography - HPLC •  Developed in 1970’s •  Uses high pressures (6000 psi) and

smaller (5 µm), pressure-stable particles •  Allows compounds to be detected at

ppt (parts per trillion) level •  Allows separation of many types of

polar and nonpolar compounds


HPLC Modalities •  Reversed phase – for separation of non-

polar molecules (non-polar stationary phase, polar mobile phase)

•  Normal phase – for separation of non-polar molecules (polar stationary phase, non-polar/organic mobile phase)

•  HILIC – hydrophilic interaction liquid chromatography for separation of polar molecules (polar stationary phase, mixed polar/nonpolar mobile phase)

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HPLC Columns


Reverse Phase Column

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HPLC Separation Efficiency


HPLC Schematic

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Gradient HPLC Schematic


HPLC of a Biological Mixture

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Gas Chromatography


Gas Chromatography •  Involves a sample being vaporized to a

gas and injected into a column •  Sample is transported through the column

by an inert gas mobile phase •  Column has a liquid or polymer stationary

phase that is adsorbed to the surface of a metal tube

•  Columns are 1.5-10 m in length and 2-4 mm in internal diameter

•  Samples are usually derivatized with TMS to make them volatile

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TMS Derivatization


Gas Chromatography

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GC-Columns

Polysiloxane


Retention Time/Index •  Retention time (RT) is the time taken by an

analyte to pass through a column •  RT is affected by compound, column

(dimensions and stationary phase), flow rate, pressure, carrier, temp.

•  Comparing RT from a standard sample to an unknown allows compound ID

•  Retention index (RI) is the retention time normalized to the retention times of adjacently eluting n-alkanes

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Compound Identification and Quantification


GC-MS Chromatogram of a Biological Mixture

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Mass Spectrometry •  Analytical method to measure the

molecular or atomic weight of samples


Typical Mass Spectrometer

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MS Principles

•  Different compounds can be uniquely identified by their mass

CH3CH2OH

N OH

HO

-CH2-

-CH2CH-NH2 COOH

HO

HO

Butorphanol L-dopa Ethanol

MW = 327.1 MW = 197.2 MW = 46.1


Mass Spectrometry

•  For small organic molecules the MW can be determined to within 1 ppm or 0.0001% which is sufficiently accurate to confirm the molecular formula from mass alone

•  For large biomolecules the MW can be routinely determined within an accuracy of 0.002% (i.e. within 1 Da for a 40 kD protein)

•  Recall 1 dalton = 1 atomic mass unit (1 amu)

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Different Types of MS

•  GC-MS - Gas Chromatography MS –  separates volatile compounds in gas column

and ID’s by mass •  LC-MS - Liquid Chromatography MS

–  separates delicate compounds in HPLC column and ID’s by mass

•  MS-MS - Tandem Mass Spectrometry –  separates compound fragments by magnetic

or electric fields and ID’s by mass fragment patterns

Masses in MS

•  Monoisotopic mass is the mass determined using the masses of the most abundant isotopes

•  Average mass is the abundance weighted mass of all isotopic components

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Isotopic Distributions

1H = 99.9% 12C = 98.9% 35Cl = 68.1% 2H = 0.02% 13C = 1.1% 37Cl = 31.9%


Isotopic Distributions

1H = 99.9% 12C = 98.9% 35Cl = 68.1% 2H = 0.02% 13C = 1.1% 37Cl = 31.9%

m/z

100

6.6

32.1

2.1 0.06 0.00

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Mass Spec Principles

Ionizer

Sample

+ _

Mass Analyzer Detector


Typical Mass Spectrum

aspirin

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Typical Mass Spectrum

•  Characterized by sharp, narrow peaks •  X-axis position indicates the m/z ratio of a

given ion (for singly charged ions this corresponds to the mass of the ion)

•  Height of peak indicates the relative abundance of a given ion (not reliable for quantitation)

•  Peak intensity indicates the ion’s ability to desorb or “fly” (some fly better than others)


Resolution & Resolving Power •  Width of peak indicates the resolution of the

MS instrument •  The better the resolution or resolving power,

the better the instrument and the better the mass accuracy

•  Resolving power is defined as: •  M is the mass number of the observed mass

(ΔM) is the difference between two masses that can be separated

ΔM M

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Resolution in MS


Resolution in MS

2847

Low resolution Instrument (Ion trap)

High resolution Instrument (TOF)

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Resolution/Resolving Power

MW(mono) = 3482.7473 MW(ave) = 3484 Blue M/ΔM = 1000 Red M/ΔM = 3000 Green M/ΔM = 10000 Black M/ΔM = 30000


Mass Spectrometer Schematic

Inlet Ion Source

Mass Analyzer Detector Data

System

High Vacuum System Turbo pumps Diffusion pumps Rough pumps Rotary pumps

Sample Plate Target HPLC GC Solids probe

MALDI ESI IonSpray API LSIMS EI/CI

TOF Quadrupole Ion Trap Orbitrap QTrap Mag. Sector FTMS

Microch plate Electron Mult. Hybrid Detec.

PC’s UNIX Mac

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Different Ionization Methods

•  Electron Ionization (EI - Hard method) –  Small molecules, 1-1000 Daltons, structure

•  Chemical Ionization (CI – Semi-hard) –  Small molecules, 1-1000 Daltons, simple spectra

•  Electrospray Ionization (ESI - Soft) –  Small molecules, peptides, proteins, up to 200,000

Daltons •  Matrix Assisted Laser Desorption (MALDI-Soft)

–  Smallish molecules, peptides, proteins, DNA, up to 500 kD


ElectronImpactIoniza.onSource

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Electron Impact Ionization

•  Sample introduced into instrument by heating it until it evaporates

•  Gas phase sample is bombarded with electrons coming from rhenium or tungsten filament (energy = 70 eV)

•  Molecule is “shattered” into fragments (70 eV >> 5 eV bonds)

•  Fragments sent to mass analyzer •  Most commonly used in GC-MS


EI Fragmentation of CH3OH

CH3OH CH3OH+

CH3OH CH2O=H+ + H

CH3OH + CH3 + OH

CHO=H+ + H CH2O=H+

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EI Breaks up Molecules in Predictable Ways

Molecular ion

Electron Impact MS of CH3OH


Soft Ionization Methods

337 nm UV laser

MALDI

cyano-hydroxy cinnamic acid

Gold tip needle

Fluid (no salt)

ESI

+ _

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Electrospray (Detail)


Electrospray (Detail)

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Electrospray Ionization

•  Sample dissolved in polar, volatile buffer (no salts) and pumped through a stainless steel capillary (70 - 150 µm) at a rate of 10-100 µL/min

•  Strong voltage (3-4 kV) applied at tip along with flow of nebulizing gas causes the sample to “nebulize” or aerosolize

•  Aerosol is directed through regions of higher vacuum until droplets evaporate to near atomic size (still carrying charges)



95%H2O/5%CH3CN 5%H2O/95%CH3CN

100 V 1000 V 3000 V

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•  Can be modified to “nanospray” system with flow < 1 µL/min

•  Very sensitive technique, requires less than a picomole of material

•  Strongly affected by salts & detergents •  Positive ion mode measures (M + H)+ (add

formic acid to solvent) •  Negative ion mode measures (M - H)- (add

ammonia to solvent)


Mass Analyzer

Mass Spectrometer Schematic

Inlet Ion Source Detector Data

System

High Vacuum System Turbo pumps Diffusion pumps Rough pumps Rotary pumps

Sample Plate Target HPLC GC Solids probe

MALDI ESI IonSpray FAB LSIMS EI/CI

TOF Quadrupole Ion Trap Mag. Sector FTMS

Microch plate Electron Mult. Hybrid Detec.

PC’s UNIX Mac

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Different Types of Mass Analyzers

•  Magnetic Sector Analyzer (MSA) – High resolution, exact mass, original MA

•  Quadrupole Analyzer (Q or Q*) – Low (1 amu) resolution, fast, cheap

•  Time-of-Flight Analyzer (TOF) – No upper m/z limit, high throughput

•  Ion Cyclotron Resonance (FT-ICR) – Highest resolution, exact mass, costly


MS Mass Accuracy

50-200 ppm Linear IonTrap 3 - 5 ppm Triple Quad 3 - 5 ppm Q-TOF 3 - 5 ppm TOF-MS 1 - 2 ppm Magnetic Sector 0.5 - 1 ppm Orbitrap 0.1 - 1 ppm FT-ICR-MS

Mass Accuracy Type

(10 ppm in Ultra-Zoom)

6E1)m

m-m(ppmexp

calcexp+∗=

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Mass Chromatograms •  Standard “output” from an LC-MS or GC-MS

experiment •  X-axis is retention time, Y-axis is signal intensity •  Total Ion Current (TIC) chromatogram is summed

intensity across the entire range of masses being detected at every point in the analysis

•  Base Peak chromatogram (BPC) is like a TIC but displays only the most intense peak in each spectrum

•  Extracted Ion chromatogram (EIC) contains one or more analytes extracted from the TIC or BPC


Mass Chromatograms of Biological Mixtures

Tomato Extract

Arabidopsis Extract

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NMR Spectroscopy


Explaining NMR

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Principles of NMR

•  Measures nuclear magnetism or changes in nuclear magnetism in a molecule

•  NMR spectroscopy measures the absorption of light (radio waves) due to changes in nuclear spin orientation

•  NMR only occurs when a sample is in a strong magnetic field

•  Different nuclei absorb at different energies (frequencies)


Protons (and other nucleons) Have Spin

Spin up Spin down

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Each Spinning Proton is Like a “Mini-Magnet”

Spin up Spin down

N

S

N

S


Principles of NMR

hν

Low Energy High Energy

N N

S S

hν

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Bigger Magnets are Better

low frequency high frequency

Increasing magnetic field strength


A Modern NMR Instrument

Radio Wave Transceiver

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NMR Magnet


Magnet Legs

Prob

e

Sample Bore

Cryogens

Magnet Coil

NMR Magnet Cross-Section

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An NMR Probe


NMR Sample & Probe Coil

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1H NMR Spectra Exhibit...

8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0

•  Chemical Shifts (peaks at different frequencies or ppm values)

•  Splitting Patterns (from spin coupling) •  Different Peak Intensities (# 1H)


Chemical Shifts

•  Key to the utility of NMR in chemistry •  Different 1H in different molecules exhibit

different absorption frequencies •  Each compound can be defined by a

unique pattern of chemical shifts (a fingerprint)

•  Chemical shifts are mostly affected by electronegativity of neighbouring atoms, bonds or groups

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Characteristic Chemical Shifts


Assigning Simple NMR Spectra

TMS

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Assigning Simple NMR Spectra


NMR Spectra Need “Fixin’” Before

After

ReferencingBaselinecorrection

Water suppression PhasingShimming

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NMR Spectra Need “Fixin’”

•  Chemical shift referencing (TMS, DSS) –  Calibrates/normalizes chemical shifts

•  Shimming –  Fixes line shape to look Lorentzian

•  Phasing –  Fixes line shape to look “absorptive”

•  Water suppression/removal –  Removes large water signal

•  Baseline correction –  Makes spectrum look flat – not wobbly


NMR Spectrum of a Biological Mixture

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Technology & Sensitivity

M mM µM nM pM fM

# M

etab

olite

s or

Fea

ture

s de

tect

ed (L

og10

)

0

1

2

3

4

Sensitivity or LDL

LC-MS or DI-MS

NMR

GC-MS Quad

GC-MS TOF

Knowns

Unknowns


Comparison NMR(withcold

probe)GC-MS DI-MS

Techniques

Metabolites Water-soluble(aminoacids,organicacids,sugars)

mainlywater-soluble(somehydrophobic)

Mainlyhydrophobic(somewater-soluble)

Typesofsamples Biofluids,plant,bacterial,animal.ssueextracts,Food

Biofluids,plant,bacterial,animal.ssueextracts,Food

Mainlybiofluids

SampleVolume 100µL(min) 30-50µL(min) 10µL

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Comparison NMR GC-MS DI-MS

Sampleprep.me 30-120min/20samples

30-120min/20samples

3-4hfor96samples

Run.me 10-90min/sample

30-60min/sample 7min/sample

DataAnalysis 30-60min/sample

30-60min/sample 1-2hfor96samples

LimitofDetec.on ~5µM ~100nM ~5nM

No.ofmetabolites ~20-150 ~20-150 ~100-180

OverlappingMetabolites

10-15 10-15 10-15

Cross-checking 10-30% 10-30% 10-30%


What’s Possible •  NMR-based metabolomics (~50-200 metabolites

identified/quantified, µM sensitivity) •  GC-MS based metabolomics (~20-120 metabolites

identified/quantified, <µM sensitivity) •  DI-MS based metabolomics (150-180 metabolites

identified/quantified, nM sensitivity) •  LC-MS based metabolomics (300-500 metabolites

identified/quantified, nM sensitivity) •  Lipidomics (3000 lipids identified and semi-

quantified, nM sensitivity) •  Specialty phytochemical, nutrient, drug and

pesticide analysis (mostly HPLC, nM sensitivity)

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2 Routes to Metabolomics

1 2 3 4 5 6 7 ppm

hippurate urea

allantoin creatinine hippurate

2-oxoglutarate

citrate TMAO

succinate fumarate

water

creatinine

taurine

1 2 3 4 5 6 7 ppm

-25 -20 -15 -10 -5 0 5

10 15 20 25

-30 -20 -10 0 10 PC1

PC2

PAP

ANIT

Control

Quantitative (Targeted) Methods

Chemometric (Profiling) Methods


Profiling (Untargeted)

-25 -20 -15 -10 -5 0 5 10 15 20 25

-30 -20 -10 0 10 PC1

PC2

PAP

ANIT

Control

Metabolite Identification

Data Reduction

Data Collection

Sample Prep

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Quantitative (Targeted)

-25 -20 -15 -10 -5 0 5 10 15 20 25

-30 -20 -10 0 10 PC1

PC2

PAP

ANIT

Control

Metabolite Identification & Quantification

Data Reduction

Biological Interpretation

Sample Prep


From Spectra to Lists Table 1 . List of 121 dansyl derivative standards and the corresponding metabolites (in bold face)

identified and quantified in a 5 -day pooled hu man urine sample by using fast LC -FTICR MS.

Compound

Retention Time (min)

Conc. in Urine (µM) Compound


Conc. in Urine (µM)

Dns-o-phospho -L-serine 0.92 <D.L. * Dns-Ile 6.35 25 Dns-o-phospho -L-tyrosine 0.95 <D.L. Dns-3-aminosalicylic acid 6.44 0.5 Dns-adnosine monophosphate 0.99 <D.L. Dns-pipecolic acid 6.50 0.5 Dns-o-phosphoethanolamine 1.06 16 Dns-Leu 6.54 54 Dns-glucosamine 1.06 22 Dns-cystathionine 6.54 0.3 Dns-o-phospho -L-threonine 1.09 <D.L. Dns-Leu -Pro 6.60 0.4 Dns-6-dimet hylamine purine 1.20 <D.L. Dns-5-hydroxylysine 6.65 1.6 Dns-3-methyl -histidine 1.22 80 Dns-Cystine 6.73 160 Dns-taurine 1.25 834 Dns-N-norleucine 6.81 0.1 Dns-carnosine 1.34 28 Dns-5-hydroxydopamine 7.17 <D.L. Dns-Arg 1.53 36 Dns-dimethylamine 7.33 293 Dns-Asn 1.55 133 Dns-5-HIAA 7.46 18 Dns-hypotaurine 1.58 10 Dns-umbelliferone 7.47 1.9 Dns-homocarnosine 1.61 3.9 Dns-2,3 -diaminoproprionic acid 7.63 <D.L. Dns-guanidine 1.62 <D.L. Dns-L-ornithine 7.70 15 Dns-Gln 1.72 633 Dns-4-acetyamidophenol 7.73 51 Dns-allantoin 1.83 3.8 Dns-procaine 7.73 8.9 Dns-L-citrulline 1.87 2.9 Dns-homocystine 7.76 3.3 Dns-1 (or 3 -)-methylhistamine 1.94 1.9 Dns-acetaminophen 7.97 82 Dns-adenosine 2.06 2.6 Dns-Phe-Phe 8.03 0.4 Dns-methylguanidine 2.20 <D.L. Dns-5-methyo xysalicylic acid 8.04 2.1 Dns-Ser 2.24 511 Dns-Lys 8.16 184 Dns-aspartic acid amide 2.44 26 Dns-aniline 8.17 <D.L. Dns-4-hydroxy -proline 2.56 2.3 Dns-leu -Phe 8.22 0.3 Dns-Glu 2.57 21 Dns-His 8.35 1550 Dns-Asp 2.60 90 Dns-4-thialysine 8.37 <D.L. Dns-Thr 3.03 157 Dns-benzylamine 8.38 <D.L. Dns-epinephrine 3.05 <D.L. Dns-1-ephedrine 8.50 0.6 Dns-ethanolamine 3.11 471 Dns-tryptamine 8.63 0.4 Dns-aminoadipic acid 3.17 70 Dns-pyrydoxamine 8.94 <D.L. Dns-Gly 3.43 2510 Dns-2-methyl -benzylamine 9.24 <D.L. Dns-Ala 3.88 593 Dns-5-hydroxytrptophan 9.25 0.12 Dns-aminolevulinic acid 3.97 30 Dns-1,3 -diaminopropane 9.44 0.23 Dns-r-amino -butyric acid 3.98 4.6 Dns-putrescine 9.60 0.5 Dns-p-amino -hippuric acid 3.98 2.9 Dns-1,2 -diaminopropane 9.66 0.1 Dns-5-hydroxymethyluricil 4.58 1.9 Dns-tyrosinamide 9.79 29 Dns-tryptophanamide 4.70 5.5 Dns-dopamine 10.08 140 Dns-isoguanine 4.75 <D.L. Dns-cadaverine 10.08 0.08 Dns-5-aminopentanoic acid 4.79 1.6 Dns-histamine 10.19 0.4 Dns-sarcosine 4.81 7.2 Dns-3-methoxy -tyramine 10.19 9.2 Dns-3-amino -isobutyrate 4.81 85 Dns-Tyr 10.28 321 Dns-2-aminobutyric acid 4.91 17 Dns-cysteamine 10.44 <D.L.

1234567ppm

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From Lists to Pathways Table 1 . List of 121 dansyl derivative standards and the corresponding metabolites (in bold face)


Compound







From Pathways & Lists to Models & Biomarkers

Table 1 . List of 121 dansyl derivative standards and the corresponding metabolites (in bold face)


Compound






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Key Informatics Challenges in Metabolomics

•  Spectra -> Lists – Data integrity and quality – Data alignment and normalization – Data reduction and classification – Assessment of significance – Metabolite identification/quantification

•  Lists -> Pathways & Biomarkers – Pathway mapping and identification – Biological interpretation

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Canadian Bioinformacs Workshops · Liquid Chromatography - HPLC • Developed in 1970’s • Uses...

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