Identify, Confirm, Solve, Explore with FTIRExplore with FTIR

Jonah Kirkwood, Ph.D. Lou Tisinger, Ph.D.

Outline

Announcement

Background & Theory

Basic Instrumentation

Sampling

Library Searching & Quantitative Analysis (Scientist in a Box)

ApplicationsQuality control Defect/contamination analysisDefect/contamination analysisTablet analysisSurface analysis

2010 – Varian Becomes a Part of AgilentA Heritage of Innovation: Varian & Agilentg g

Exciting Announcement!

Agreement signed!

Out-of-lab & entry-level FTIR solutions

What can you measure with infrared light?

IR spectroscopy can be used to analyze samples from all three states of matter – it can be used to analyze gases, liquids, and solids.

Infrared spectroscopy has been a cornerstone of analytical measurements for over 50 years.

Routine measurement, used for qualitative and quantitative analysis

What is infrared light?

Infrared light is a portion of the electromagnetic spectrum, and is just beyond the visible portion of sunlight.

ays

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D-IR ioro

wav

e

mm

a

ctric

Pow

er

X-R

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UV

Visi

NIR MID

FIR

Rad

Mic

r

4000 400Frequency in cm-1

Gam

Elec

The electromagnetic spectrum can be divided into specific regions, including: Gamma rays, X-Rays, Ultraviolet, Visible, Infrared, Microwave and Radio

For convenience of applications and instrumentation, the infrared spectrum is divided into near-, mid-, and far-infrared radiation. The most commonly used region is the

id i f d

Microwave and Radio.

mid-infrared.

IR Spectroscopy

O

IR energy causes molecular vibrationsEvery different type of chemical bond that absorbs

H

O

H

infrared light naturally vibrates at a specific frequency. When the frequency of IR light matches the frequency of vibration of atoms bonded together, the light will be

O

absorbed.The amount of energy absorbed is proportional to the strength of a bond.

H H

O

gThe set of IR absorbances for a sample is referred to as an IR spectrum

Io IO

H H

H H

Infrared Spectrum

The IR spectrum of a sample is a plot of the amount of IR energy (y-axis) that is absorbed at frequencies (x-axis) in IR the region of the electromagnetic spectrumof the electromagnetic spectrum.

ceA

bsor

banc

4000 3500 3000 2500 2000 1500 1000 500 Wavenumber (cm-1)

Infrared Spectrum

The IR spectrum of a sample is a plot of the amount of IR energy (y-axis) that is absorbed at frequencies (x-axis) in IR the region of the electromagnetic spectrumof the electromagnetic spectrum.

Every sample has a unique IR spectrum; y p q p ;an IR spectrum can serve as a compound’s fingerprint.

1500200025003000 35004000Wavenumbers (cmWavenumbers (cm--11))

1000

• The frequency where atoms bonded together (commonly referred to as

Basic Interpretation• The frequency where atoms bonded together (commonly referred to as

“functional groups”) absorb correspond to the strength of the bond; stronger bonds absorb at higher frequencies, vice-versa.

• Every functional group absorbs at its own frequency making it possible to

0.30 1750 cm-1 1540 cm-1

• Every functional group absorbs at its own frequency, making it possible to elucidate chemical structure of a material from its IR spectrum.

0 30

0.25

0.20

nce

3300 cm-1

N-H Stretch2900 cm-1

C H S h

1750 cmC=O Stretch N-H Bending

0.15

0.10Abs

orba

n C-H Stretch

4000 3000 2000 1000

0.05

0.00

4000 3000 2000 1000Wavenumber (cm-1)

Interpreting Spectra

Instrumentation

• First IR spectrometers were dispersion based; each frequency (or wavelength of light) is isolated oneq y ( g g )at a time, using either a prism or a grating

• Low energy throughput• Time-consuming• Limited sampling options

Detector(s)

SampleGrating

IR SourceSlit

Instrumentation

• Current technology is Fourier Transform Infrared (FTIR)• Sample is exposed to all wavelengths of IR radiation at once• Sample is exposed to all wavelengths of IR radiation at once•• Fourier TransformFourier Transform is a powerful mathematical operation that

decomposes the signal into its individual frequencies –analogous to breaking down a musical chord into its individual notesa a ogous to b ea g do a us ca c o d to ts d dua otes

• The “heart” of an FTIR is an interferometerRecognized over 100 years ago for spectroscopic applicationsMathematics very complex and time consumingMathematics very complex and time-consumingNot possible for routine measurements until the advent of modern computers (late 1970’s)

Instrumentation

Reference

LaserIR Source

Moving MirrorLaser MirrorLaser

Detector

Fixed Mirror

SampleCell

IR Detector

Cell

Instrumentation

1. Multiplex (Fellgett) advantage:All wavelengths scanned simultaneously- Reduction in data collection time by a factor of N y- Increase in signal-to-noise ratio (SNR) by a factor of N1/2

(N is the number of resolution elements)

2 Throughput (Jacquinot) advantage:2. Throughput (Jacquinot) advantage:Greater amount of source energy to detector- No rectangular slit aperture- IR detectors noise-limiting component- ~150 times greater throughput versus dispersive

3. Registration (Connes) advantage:Fixed internal wavelength reference sourceFixed internal wavelength reference source. - He-Ne laser (632.8 nm) - Used for mirror control and data acquisition timing

FTIR Sampling Modes

TransmissionTransmission(liquids, gases, powders, films)

Reflectance Reflectance (liquids, thins films, bulk materials)

Diffuse Reflectance Diffuse Reflectance (mainly powders)

SAMPLESAMPLEdp

ATRATR(all, except gases)

SAMPLESAMPLE

CRYSTAL (IRE)CRYSTAL (IRE)

p

CRYSTAL (IRE)CRYSTAL (IRE)

Transmission: Sample Preparation for IR

Cast Films - for solid powders and polymersand non volatile solvents• Dissolve in a volatile solvent or melt.• Apply liquid to an infrared transparent window, allow to

dry/solidify.• With luck and skill, could get film neither too thick nor

too thin, without excessive baseline tilt from crystalline scattering, without cracking or flaking off the window, which would produce a good spectrum.

Transmission: Mulls

Mulls - For powders which could not be dissolved, or would not melt and flow.

Sample ground in a agate mortar with a Mulling Agent.

M ll d l li d t i f i f d i dMulled sample applied to pair of infrared windows as a capillary film.

With skill and luck, could get a mull that was not hi hi k l d d didtoo thin or thick, properly ground, and did not

react with mulling agent or windows.

Different mulling agents required to get a complete infrared spectrum (all absorb in the IR and interfere in different regions of the spectrum.)

Transmission: Pressed Pellets

For solids and powders.• Sample ground “talcum powder fine” mixed with finely ground• Sample ground talcum powder fine , mixed with finely ground

NaCl or KBr powder at ~1% w/w sample/salt.• Salt must be absolutely dry.• Salt may react with sample (ion exchange).• Mixture placed in die, compressed under several tons of pressure

to form an infrared transparent pellet.• With skill and luck, a clear pellet that was not too thick or thin, and

not cloudy or hazy (from large sample particles) would be formed.

Transmission: Gas Analysis

Gases much weaker infrared absorbers, use longer pathlength to , g p gincrease absorbance signal intensity.Typical gas cells:• 10 cm single-pass.• Multi-pass gas cells.Windows mirrors (in multi-pass cells) cell

10 cm Gas Cell

Windows, mirrors (in multi pass cells), cell body and fittings must be compatible with sample.

E i t l li ti “ i ”Environmental applications use “open-air” or “fence-line” techniques.

Multi-pass Gas CellMulti pass Gas Cell

Transmission: Liquid Cells (mainly for quantitative analysis)

Two infrared transparent windows, separated by a metal or polymer (typ PTFE) spacer

(mainly for quantitative analysis)

by a metal or polymer (typ. PTFE) spacer, 0.05 to 1 mm path length.

Cell Types:Cell Types:

• “Demountable”, two windows and assorted spacers that can be interchanged.“S l d A l ” i d l d ith l d• “Sealed Amalgam”, windows sealed with lead-amalgam spacer, can not be disassembled.

• Variable-Path, two fixed windows in threaded sleeve.

High-pressure, high-temperature configurations are also available.

Transmission: Liquid Analysis(exciting NEW technology)(exciting NEW technology)

Two infrared transparent windows form a sealed fixed thl ht llpathlenght cell

• TumblIR – fixed 100 µm pathlength is ideal for lubricant analysis.• DialPath – three selectable pathlengths for increased flexibilityDialPath three selectable pathlengths for increased flexibility,

ease-of-use and high performance in multi-application environments.

Reflectance: Specular Reflectance

• For thin coatings on reflective surfaces, also for bulk polymers (qualitative only)polymers (qualitative only).

• Angle of incidence and collection varied, shallower angles increasing pathlength through the organic coating (grazing-angle reflectance).

• Quantitative applications mostly for determination of surface layer thickness, such as lubricants on magnetic disks or surface coatings and modifications in semiconductor manufacturing.

SSample

Reflectance: Reflectance-Absorbance (or transflectance)

Thin film on strongly fl ti b t t

(or transflectance)

nce

reflecting substrate

The substrate:f

10

12

14

Ref

lect

aNo absorbance featuresHigh refractive indexMetals (IR opaque) 4

6

8

Semiconductors

Reflection spectrum is0

2

4

3000 2500 2000 1500 1000 500Reflection spectrum is transmission-like

3000 2500 2000 1500 1000 500

Wavenumber (cm-1)

Specular Reflectance: Bulk

Extruded pellet

specular reflectance r

refractive index n

absorption index k

Wavenumber (cm-1)2000 1000

Diffuse Reflectance (DRIFT)

For powders and other finely ground material.

• Sample ground, mixed with salt (KBr) in same proportions as for pressed pellet.

• Mixture placed in DRIFT cup, infrared spectrum acquired using pure KBr in another sample cup asacquired, using pure KBr in another sample cup as the background.

• Common technique for Sampling in the Near Infrared, lid t bl te.g., solid tablets

R• Response depends on• particle size (smaller stronger)particle size (smaller stronger)• packing (tighter less diffuse)• dilution often important

(concentration ~1%)( %)

Diffuse Reflectance Comparisonto Transmission Pellets

Diffuse ReflectanceDiffuse Reflectance KBrKBr PelletPellet

to Transmission Pellets

Diffuse ReflectanceDiffuse Reflectance• Run as-is• Quantification

KBrKBr PelletPellet• Difficult initial setup• Extra sample preparation

• Reproducible• Useful MIR and NIR

p p p• Sample may change on

preparation

Attenuated Total Reflectance (ATR)

For liquids and solids, especially polymers.

• Some crystals coated with surface-active agent that bindsSome crystals coated with surface active agent that binds to specific analytes.

• Infrared beam internally reflects through the crystal, i t ti ith l i t t ith th t l finteracting with sample in contact with the crystal surface.

• Surface effect wavelength dependent, shorter wavelengths (higher wavenumbers) interact less.

Liquid sample

MultiMulti‐‐bounce Crystalbounce CrystalSingleSingle‐‐bounce Crystalbounce CrystalTo DetectorFrom Interferometer

• Manipulate samples under magnification

FTIR Microscope• Manipulate samples under magnification

• Isolate areas of interest for interrogation• Work with very small samples, down to 10 micrometers or smaller

• Scan in all of FTIR sampling modes: Transmission, Reflection, Grazing Angle reflection, and ATR

• Operate in single-point mode (single spectrum) and imagingOperate in single point mode (single spectrum) and imaging (IR-picture –thousands of spectra covering a sample area)

Library Searching

• Users need not have spectral interpretation skills

• IR Spectra are well-suited to library searching owing to• IR Spectra are well-suited to library searching, owing to feature-rich spectra

• Hundreds of thousands of compounds are available in pcommercial search libraries

• Search programs allow users to create their own libraries

• Simply scan and click on “Search” icon and select libraries to search

Search Library

“unknown”unknown

M t f ll B L b t L

Quantitative Analysis• Most common follows Beer-Lambert Law

• A = єbc, where “A is absorbance; “є” is absorption coefficient; “b” is pathlength; and “c” is concentration

• Spectral bands are well-isolated• Standards concentrations bracket expected unknown• Best if done with liquids or gases (in transmission)q g ( )• ATR can be used with liquids if concentration is sufficient to provide

linear calibration curve • Mid-IR typical detection limits around 0.1%yp

M t f ll B L b t L

Quantitative Analysis• Most common follows Beer-Lambert Law

• A = єbc, where “A is absorbance; “є” is absorption coefficient; “b” is pathlength; and “c” is concentration

• Spectral bands are well-isolated• Standards concentrations bracket expected unknown• Best if done with liquids or gases (in transmission)q g ( )• ATR can be used with liquids if concentration is sufficient to provide

linear calibration curve • Mid-IR typical detection limits around 0.1%yp

• More complex systems use chemometrics algorithms (PCR or PLS)• Beer-Lambert Law calibrations are easy to set-up

S t d d d h i t ( t ti ll ith• Scan standards and assess chemistry (concentrations – usually with chromatography or wet chemistry)

• Use peak area for analyte, and plug in concentration of standards in programprogram

Quantitative Analysis

Scan unknown, and use curve to predict concentration:

The Agilent 600-IR SeriesCommon ApplicationsCommon Applications

Application #1

Quality control during the                                              manufacturing of a fuel cap for a vehicle.

Problem: During production, fuel caps are being contaminated by an unknown compound.  The contaminants were ~20 ‐ 300 µm in size.

Approach: Analysis by micro‐ATR with a 610‐IR single element detector.  Benefit ‐ samples could be analyzed “as is” with no preparation.  

660 µm

Yellow fuel cap0.08

Materials: QC of Fuel Cap

00 µm

AATR 0.04

Absorba

nce

5

3000 2000 10004000Wavenumber (cm‐1)

0.00

A

Normal Composition

660 µm

Yellow fuel cap0.08

Materials: QC of Fuel Cap

00 µm

AATR 0.04

Absorba

nce

5

3000 2000 10004000Wavenumber (cm‐1)

0.00

A

Red contaminant0.08

Normal CompositionContaminant / Defect

0.04Absorba

nce

500 µmB ATR

3000 2000 10004000Wavenumber (cm‐1)

0.00

A

660 µm660 µm

Spectral similarities

QC of Fuel Cap

Red contaminant

Yellow fuel cap0.080.08

0.04

orba

nce

0.04

orba

nce

Abso

Abso

3000 2000 10004000Wavenumber (cm‐1)

0.003000 2000 10004000

Wavenumber (cm‐1)

0.00

Significant spectral differences

QC of Fuel Cap

Red contaminant

Yellow fuel cap0.080.08

0.04

orba

nce

0.04

orba

nce

Abso

Abso

3000 2000 10004000Wavenumber (cm‐1)

0.003000 2000 10004000

Wavenumber (cm‐1)

0.00

Spectral subtraction

QC of Fuel Cap

0.08 Result of spectral subtraction0.08

0.04

orba

nce

0.04

orba

nce

Abso

Abso

3000 2000 10004000Wavenumber (cm‐1)

0.003000 2000 10004000

Wavenumber (cm‐1)

0.00

Search spectral databases:in‐house or commercially‐available

QC of Fuel Cap

in house or commercially availableIn‐house

0.08 Result of spectral subtraction0.08

0.04

Absorba

nce

0.04

Absorba

nce

Commercial3000 2000 10004000

Wavenumber (cm‐1)

0.00

3000 2000 10004000

Wavenumber (cm‐1)

0.00

In‐house search software is standard. 

QC of Fuel Cap

Simple to create custom‐built libraries of proprietary data.

In‐house

Ideal for QA/QC applications such as identification and verification analyses.

Easy: Single‐click search functions.

Res Pro directly interfaces to databases.y

Access to the largest FTIR libraries in the world – with dedicated polymer/material.Commercial

Advanced data‐mining capabilities: interpretation, classification, identification, and verification of unknown compounds.

Summary of Application #1

Quality control during the                                              manufacturing of a fuel cap for a vehicle

Problem: During production, fuel caps are being contaminated by an unknown compound.  The contaminants were ~20 ‐ 300 µm in size.

Solution: Analysis by micro‐ATR with a 610‐IR single element detector.  Spectra were collected in 5 seconds, compared visually and then subtracted to gain a better understanding of the contaminant Thesubtracted to gain a better understanding of the contaminant.  The spectra were compared to in‐house and commercially‐available spectral libraries to identify the source of the contamination in the manufacturing process (wearing of a plastic o‐ring)manufacturing process (wearing of a plastic o ring). 

Alternate approachDepending on the QA/QC application, consider using a 660‐IR + video 

GladiATR (integrated CCD camera)

++

Failure Analysis

Component failure analysis of vehicle spark plugs

Problem Soon after installation the spark plugs in a fleet ofProblem: Soon after installation, the spark plugs in a fleet of commercial vehicles begin to fail at an unacceptable rate indicating a problem with the engines.  Excessive deposits accumulate on spark plugs even after low mileage and corrective measures are requiredplugs even after low mileage, and corrective measures are required.

Approach: Analysis by micro‐ATR using Agilent’s patented large sample objective with a 610 IR single element detector Benefit spark plugobjective with a 610‐IR single element detector.  Benefit – spark plug samples could be analyzed “as is” with no preparation, and even small deposits can be investigated. 

Note: the typical FTIR approach would involve scraping the surfaceof the spark plug to isolate a small portion from the area of interest prior to analysis. 

Agilent’s LS Objective with ATR

Front view of slide‐on ATR in                    Side view during ATR analysis of a defective                  Agilent’s Patented Large Sample Objective

g yspark plug using the Large Sample Objective

Agilent’s LS Objective with ATR

Micro‐ATR                         

1. White lubricant

sampling locations

2 Black contaminant2. Black contaminant

3. Defective electrode tip (terminal)

White lubricant0.4

ance

0.2

0.0

Abs

orba

Black contaminant0.4

e

3000 2000 1000 4004000Wavenumber (cm-1)

0.2

Abs

orba

nce

3000 2000 1000 4000.0

4000Wavenumber (cm-1)

Defective0.4

Sid i d i l l i i h

electrode tip

0.2

Abs

orba

nce

Side view during sample analysis with            Agilent’s Patented Large Sample Objective. 

FTIR data was acquired in <5 sec. 3000 2000 1000 4000.0

4000Wavenumber (cm-1)

Search contaminant spectrumagainst a commercial library

Black contaminant

0.4

e

White lubricant

Defective

0.2

bsor

banc

e Defectiveelectrode tip

0.0

Ab

3000 2000 1000 4004000Wavenumber (cm-1)

Result of search: siloxane-containing compound

Methyl Siloxane

What do siloxanes do to an engine?

Volatile methyl siloxanes convert into silicon dioxide (SiO2) as y ( 2)combustion takes place in the engine.  

The SiO2 combines with other elements in the gas, and with the 2 lubrication oil to form a hard matrix that accumulates on the combustion surfaces.

If run unchecked, severe damage can occur to vehicle components (including: valves, pistons, piston rings, spark plugs , etc.) necessitating premature servicing and costly repairs.

Summary of Application

Component failure analysis of vehicle spark plugs

Problem The faulty spark plugs had visible deposits that wereProblem: The faulty spark plugs had visible deposits that were encrusted on the side and center electrodes of the terminal.  

Approach: Although difficult to sample using conventional meansApproach: Although difficult to sample using conventional means,               FTIR analysis with the LS objective revealed that the deposits were derived from oil & fuel additives.

Recommendation: Correct the mechanical condition with necessary repairs as it is likely that fuel/oil is leaking past worn valve guides and/or piston rings into the combustion chamber causing hard startingand/or piston rings into the combustion chamber causing hard starting and misfiring.   

Fine structure analysis of functional film in LCD

Visible Image (by 620‐IR built‐in CCD)SEM Image IR Image at 1697 cm‐1

~ 5 μm

0.35

ity~ 5 μm

Area Intens

IR imaging area: 35 x 35 μm

35 μm

0.00

0 201697

0.20

0.15

0.10

Absorbance

Around Bead

Bead

Difference: Bead – Around Bead

1800 1700 1600 1500 1400 1300 1200 1100 1000 900

0.05

0.00

A

Wavenumbers (cm‐1)

Fine structure analysis of functional film in LCD

Visible Image (by 620‐IR built‐in CCD)SEM Image IR Image at 1697 cm‐1

~ 5 μm

0.35

ity

High resolution spectra (1.1 µm) from several small beads and their surroundings provided a ~ 5 μm

Area Intenssmall beads and their surroundings provided a 

comprehensive means of troubleshooting product defects in the manufacturing of functional films in LCD screens.

IR imaging area: 35 x 35 μm

35 μm

0.00

0 201697

0.20

0.15

0.10

Absorbance

Around Bead

Bead

Difference: Bead – Around Bead

1800 1700 1600 1500 1400 1300 1200 1100 1000 900

0.05

0.00

A

Wavenumbers (cm‐1)

Pharmaceutical Application

Identification of a pharmaceutical tablet’s originusing FTIR and principal component analysis.using FTIR and principal component analysis.

Challenge: Routine analysis of pharmaceutical tablets can be expensive and time consuming using conventional wet chemistry methods.  To g g ydemonstrate the use of both mid‐IR and near‐IR spectroscopy in pharmaceutical applications – pioneer vs. generic drug. 

Approach: Analysis by (1) ATR and (2) Integrating sphere with a 660‐IR.  Benefit ‐ samples could be analyzed “as is” with no preparation.  

Pharmaceutical tablet analysis

Need for quick differentiation between pioneer and generic drugsas well as suspected counterfeit pharmaceutical tablets.

The active pharmaceutical ingredient in Zyrtec® tablets ‐ commonly referred to as Cetirizine hydrochloride.This study focused on 6 Cetirizine‐containing tablets:

Zyrtec®/cetirizine samples used

Mid‐IR

Sampling techniquesMid‐IR

Mid‐IR Overview of ATR sampling.  A sample is placed on the surface of an internal reflective element crystal.  The depth of penetration is typically on the order of a few microns.  Advantageously for ATR, many samples may be analysed without the need for sample preparation, whether they be 

Near‐IRNear‐IR

solids, liquids, or gels.

Pharmaceutical tabletPharmaceutical tablet

Crystal Crystal (IRE)(IRE)

From InterferometerTo Detector

Mid‐IR

Sampling techniquesMid‐IR

Near‐IR Overview of ATR sampling.  A sample is placed on the surface of an internal reflective element crystal.  The depth 

Overview of IntegrateIRTM NIR accy. Samples or sample containers are placed on the accessory.  No sample preparation or cleaning of surface between analyses isof penetration is typically on the order of a few microns.  Advantageously for ATR, many samples may be analysed without the need for sample preparation, whether they be 

cleaning of surface between analyses is required.  

Particularly beneficial for turbid, translucent, or opaque refractory materials which exhibit

Near‐IRNear‐IR

solids, liquids, or gels.or opaque refractory materials which exhibit significant scattering effects as well as for samples that distort the IR beam, such as lenses. 

Baffle

Pharmaceutical Pharmaceutical tablettablet

Detector  port

Entrance port

Area ofArea ofArea of Area of SurfaceSurface

Mid‐IR

Sampling techniquesMid‐IR

Both spectral regions have the capability of identifyingactive pharmaceutical ingredients (API) and excipients ofpharmaceutical products.

Near‐IRNear‐IR

p p

Each region has advantages for the differentiation ofZyrtec® and its cetirizine generic counter parts.

6 Cetirizine-containing tabletsMid‐IR Overlaid Mid‐IR spectra of six cetirizine‐containing tablet samples 

(one tablet from each distributor) used in this study

0.05

0.04

0.03

0 02bance

(one tablet from each distributor) used in this study

3200 2800 2400 2000 1600 1200 8003600

Wavenumber (cm‐1)

0.02

0.01

0.00

Absorb

Near‐IR

Wavenumber (cm 1)

Overlaid Near‐IR spectra of six cetirizine‐containing tablet samples 

6492.7 6269.1

5170.34775.3

4386.60.55

0.45

0.35

bance

(one tablet from each distributor) used in this study

0.25

0.15

0.05

Absorb

11000 10000 9000 8000 7000 6000 5000 4000Wavenumber (cm‐1)

PCA analysis of Near-IR dataNear‐IR

6492.7 6269.1

5170.34775.3

4386.60.55

0.45

0.35

0.25orba

nce

0.25

0.15

0.05

Abso

11000 10000 9000 8000 7000 6000 5000 4000Wavenumber (cm‐1)

AB

( )

Each tablet was run in triplicate, 

CVS (D) C

F

5 tablets per distributor were analyzed (6 distributors total).

3 × 5 × 6 = 90 Near‐IR spectra f l

A ‐ Tradaxine® (SBL Pharmaceutical)B ‐ Zyrtec® OTC (McNeal Consumer Health)C ‐ Zyrtec (Merck Medco—Pfizer)D C ti i i (CVS D R dd ’ L b)Rite Aid (E)for PCA clustering D ‐ Cetirizine (CVS—Dr. Reddy’s Lab)E ‐ Cetirizine (Rite Aid—Dr. Reddy’s Lab)F ‐ Cetirizine (Walmart—Perrigo)

Three component PCA of Near‐IR data

PCA analysis of Near-IR dataDifferent colors assignedB

A ‐ Tradaxine® (SBL Pharmaceutical)B ‐ Zyrtec® OTC (McNeal Consumer Health)C ‐ Zyrtec (Merck Medco—Pfizer)

Different colors assignedto the different distributors.

CVS (D)

AB

C

F

A ‐ Tradaxine® (SBL Pharmaceutical)B ‐ Zyrtec® OTC (McNeal Consumer Health)C ‐ Zyrtec (Merck Medco—Pfizer)

CVS (D)A ‐ Tradaxine® (SBL Pharmaceutical)B ‐ Zyrtec® OTC (McNeal Consumer Health)C ‐ Zyrtec (Merck Medco—Pfizer)C  Zyrtec (Merck Medco Pfizer)D ‐ Cetirizine (CVS—Dr. Reddy’s Lab)E ‐ Cetirizine (Rite Aid—Dr. Reddy’s Lab)F ‐ Cetirizine (Walmart—Perrigo)

Rite Aid (E)

F C  Zyrtec (Merck Medco Pfizer)D ‐ Cetirizine (CVS—Dr. Reddy’s Lab)E ‐ Cetirizine (Rite Aid—Dr. Reddy’s Lab)F ‐ Cetirizine (Walmart—Perrigo)

Rite Aid (E)

C  Zyrtec (Merck Medco Pfizer)D ‐ Cetirizine (CVS—Dr. Reddy’s Lab)E ‐ Cetirizine (Rite Aid—Dr. Reddy’s Lab)F ‐ Cetirizine (Walmart—Perrigo)

Three component PCA of Near‐IR data

Output can be a powerful visual tool for the investigation of the variance of spectral data setsspectral data sets. 

While some of the clusters overlap, there is still a clear separation of the samples based on their origin. 

Although the CVS & Rite Aid samples share the same manufacturer there existsAlthough the CVS & Rite Aid samples share the same manufacturer, there exists a class separation, suggesting that different excipient formulations are used. 

The PCA calibration can equally be used to predict the origin of an unknown ti i i t bl t if th di ti t h i l tt ib t th t bl tcetirizine tablet even if there are no distinct physical attributes on the tablet. 

Summary of Application

Identification of a pharmaceutical tablet’s originusing FTIR and principal component analysis.

Challenge: Routine analysis of pharmaceutical tablets –pioneer vs. generic drug. 

Solution: Both Mid‐IR and Near‐IR can be used for this application.

ATR accessories can be simple and cost‐effective – require cleaning. 

Near‐IR sampling with an Integrating Sphere accessory is also an invaluable tool for such analyses: high‐throughput & hassle free replacement to existing chromatography or wet chemistry techniques. Its ability to acquire spectra of a sample through a plastic bag, glass vial, or a reagent bottle can be a significant asset in pharmaceutical applications.

Summary

• FTIR is an extremely versatile analytical tool• Easy to use, flexibility in analysis• Used for qualitative and quantitative analysis

• Mature technique • Many different spectral libraries, consisting of 100’s of thousand

of compounds are available• Many sampling accessories are available for virtually any y p g y y

sample configuration/type

FTIR is applied to analytical problems in many different industriesFTIR is applied to analytical problems in many different industries, spanning chemical, materials, biomedical, and pharma