i ndependent c omponents a nalysis i ndependent c omponents a nalysis applications of ica douglas n....
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INDEPENDENT COMPONENTS ANALYSIS INDEPENDENT COMPONENTS ANALYSIS
Applications of ICA
Douglas N. Rutledge, Delphine Jouan-Rimbaud Bouveresse
50010001500200025003000350040000
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cm-1
Information Hidden in MIR Spectra
Source : R.Aries, D. Lidiard, R. Spragg, Spectrosc. Internat., 2(3) 41-44
ICA on 100 Mid-Infrared spectra
• Samples : a single polystyrene film
• Mid-IR spectra taken at end of production line
• Acquired from 4000cm-1 to 400cm-1, at 1 cm-1
• Pre-treatment of spectra :- normalised between 0 and 1- neither centred nor standardised
PC2 CO2 & H2O
Results of a PCA on the polystyrene MIR data
PC6
Interferogram & derivativePC5
Interferogram & derivative
PC5-PC6 Scores Plot
-0.1
0
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-0.2 0 0.2 0.4
PC5
PC
6
61
IC2/7 signal looks like water vapour spectrum
Due to variations in moisture content of air
IC3/7 signal looks like spectrum of CO2
Due to variations in CO2 content of air
IC4/7 signal looks like beats of a simple interferogram
Due to variations in optical path of polystyrene sample ?
IC7/7 signal looks like first derivative of average MIR spectrum
Due to one spectrometer (N°61) being badly adjusted (frequency shift)
Elimination of artifacts
Monitoring changes in oils during heating using 3-D Fluorescence Spectroscopy
Rayleigh scattering
Ramanscattering
ex
(nm)
em (
nm)
280 300 320 340 360 380 400 420 440
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3-D Fluorescence Spectra of Oils during Heating
ex
(nm)
em (
nm)
IC1
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IC1 = Rayleigh + Raman
ex
(nm)
em (
nm)
IC2
280 300 320 340 360 380 400 420 440
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IC2 = Polyphenols
ex (nm)
em (
nm)
IC3
280 300 320 340 360 380 400 420 440
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IC3 = Chlorophyll…
Antioxydant influence of catechin on rats after hyperlipidic diets, monitored using a LC-MS based metabolomic
approach
The data • Samples• Male Wistar rats (n = 8/group) fed for 6 weeks normo- (5% diet w/w) or hyper- lipidic (15 and 25%) diets (CT05 / HF15 / HF25)
• With or without catechin supplementation (0.2% w/w) (NP / PP) (polyphenolic antioxidant - helps prevent inflammatory and coronary diseases)
• Urines collected 17 and 38 days after diets were given (T17 / T38)
• Technique• Analysed by mass spectrometry on a LC-QToF (m/z 100-1000; positive ionization)(HPLC Alliance 2695, Symmetry® RP18 column, Micromass Qtof-Micro / Waters)
• Pretreatment• Intensities of peaks transformed to log(X+1)
• Variables sorted in order of decreasing variance(later as function of Retention Time)
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34
56
78
910
0
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Log(raw LC-MS data)
Log(raw LC-MS data)
Independent Components Analysis
Extract “pure signals” from observed mixtures
- “pure signals” => “Loadings”
- “proportions” of “pure signals” to mixtures = “Scores”
2 4 6 8 10 12 14 16 18 20 22 24
1.51.61.71.81.9
IC1 (Fat)
5 10 15 20 25 30 35
1.51.61.71.81.9
IC1 (Catechine)
5 10 15 20 25 30 35
1.51.61.71.81.9
IC1 (Days)
ICA on Log(Data)
ICA on Log(Data)
2 4 6 8 10 12 14 16 18 20 22 24
-1.5
-1
-0.5
IC2 (Fat)
5 10 15 20 25 30 35
-1.5
-1
-0.5
IC2 (Catechine)
5 10 15 20 25 30 35
-1.5
-1
-0.5
IC2 (Days)
2 4 6 8 10 12 14 16 18 20 22 24
-1
-0.5
0IC3 (Fat)
5 10 15 20 25 30 35
-1
-0.5
0IC3 (Catechine)
5 10 15 20 25 30 35
-1
-0.5
0IC3 (Days)
2 4 6 8 10 12 14 16 18 20 22 24
-1
-0.5
0IC3 (Fat)
5 10 15 20 25 30 35
-1
-0.5
0IC3 (Catechine)
5 10 15 20 25 30 35
-1
-0.5
0IC3 (Days)
ICA on Log(Data)
2 4 6 8 10 12 14 16 18 20 22 24
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Fat)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Catechine)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Days)
2 4 6 8 10 12 14 16 18 20 22 24
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Fat)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Catechine)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC4 (Days)
ICA on Log(Data)
2 4 6 8 10 12 14 16 18 20 22 24
-1
-0.5
0
IC5 (Fat)
5 10 15 20 25 30 35
-1
-0.5
0
IC5 (Catechine)
5 10 15 20 25 30 35
-1
-0.5
0
IC5 (Days)
2 4 6 8 10 12 14 16 18 20 22 24
-1
-0.5
0
IC5 (Fat)
5 10 15 20 25 30 35
-1
-0.5
0
IC5 (Catechine)
5 10 15 20 25 30 35
-1
-0.5
0
IC5 (Days)
ICA on Log(Data)
2 4 6 8 10 12 14 16 18 20 22 24
-1
-0.5
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IC5 (Fat)
5 10 15 20 25 30 35
-1
-0.5
0
IC5 (Catechine)
5 10 15 20 25 30 35
-1
-0.5
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IC5 (Days)
2 4 6 8 10 12 14 16 18 20 22 24
-0.8-0.6-0.4-0.2
00.20.4
IC6 (Fat)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC6 (Catechine)
5 10 15 20 25 30 35
-0.8-0.6-0.4-0.2
00.20.4
IC6 (Days)
ICA on Log(Data)
200
400600
800
24
68
10
-4
-2
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2
IC2
IC2 “Loadings”
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400600
800
24
68
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-6
-4
-2
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IC3
IC3 “Loadings”
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68
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IC5
IC5 “Loadings”
Mid-Infrared analysis of edible oilsheated at 190° for 3 hours
ICA applied to Mid-Infrared spectra
180 spectra acquired every 3 minutes over 3 hours during flat heating at 190°C
PCA Loadings
PCA Scores
ICA Signals
ICA Scores
Mid-IR spectrum of CO2
Scores of samples on IC9 as a function of heating time
Mid-IR spectrum cis-trans isomerisation
Scores of samples on IC2 as a function of heating time
ICA applied to Raman hyperspectral images
Hyperspectral images acquired for an authentic and a suspect pharmaceutical pill
M Boiret, D N Rutledge, N Gorretta, Y-M Ginot, J-M RogerUtilisation de la microscopie Raman et des methodes chimiometriques pour la detection de comprimes contrefaits, SpectrAnalyse, 2014, in press
Images collected using a PerkinElmer RS400 system
Microscope coupled to spectrophotometer with 785nm 400mW laser
CCD sensor (Charge-Coupled Device)
Sample on a motorized stage with a pitch of 50 microns
Raman spectra acquired from 3200cm -1 to 100cm -1 Spectral resolution 2 cm -1
26 000 spectra on a surface of about 8mm * 8mm
ICA_by_Blocks applied to authentic and suspect pills
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ICs
Low
est
Corr
ela
tions
Comprimé référence
Comprimé suspect
ICA Proportions
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Raman shift (cm-1)
Rel
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t.
Pure API
Signal 1
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Raman shift (cm-1)
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Pure Excipient 1
Signal 2
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Raman shift (cm-1)
Rel
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t.
Pure excipient 3
Signal 3
ICA Signals& Reference spectra
R=0.99
R=0.99
R=0.98
Authentic pharmaceutical pill
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Raman shift (cm-1)
Int.
S2
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Raman shift (cm-1)
Int.
S1
ICA Proportions ICA Signals
Suspect pharmaceutical pill
ICA Signals& Reference spectrum
(Metformine)
Suspect pharmaceutical pill
Compare ICA signals with spectral database
200 400 600 800 1000 1200 1400 1600 18000
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Raman shift (cm-1)
Rel
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t.
Signal 1
Metformine
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Raman shift (cm-1)
Rel
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t.
Signal 2
Avicel
ICA Signals& Reference spectrum
(Avicel)
R=0.96R=0.99
ICA can be applied to data usually analysed using PCA
Contributions of variables are easier to interpret
CONCLUSION