Chemical Microanalysisfor Industry

State-of-the-Art Analysis for hireMedical Device Problem Solving

Polymer Problem SolvingIndustrial Problem Solving

Asbestos Analysesetc., etc., etc.

byJohn Donohue201-294-2581

Hello. I’m John Donohue and this is the best Infrared Microscope ever made byany manufacturer: Nicolet’s IR-Plan Research Microscopemounted on a Magna 560 MainbenchThis amazing instrument allows my Labto obtain the Chemical Identity, via the Infrared Spectrum, of an area as small as 10 microns by 10 microns (10μX10μ). That’s as small as 9 red blood cells placed in a 3X3 square.

When you can chemically identify objects that small you can perform such amazing investigations that theycan often depart completely from the expected and traditional uses of Infrared Spectroscopy, as you will see.

These documents will describe the type of analyses I perform for Industry and Publication using this instrument and the other equipment in my Laboratory.

Part 1: Introduction to the Technology and Method

Mirrored “Lampshade”

Mirrored “Flying Saucer”

Hard Silicon Surface for ATR “Contact” Spectra

My IR-Plan is usually set up with Two Reflachromats:One For Reflection And Transmission, The Other Dedicated To ATR

More “Specialized Reflachromats” and Visible Light Objectives are available, if needed

… and Visible Light Objectives forVisible and Polarized Light Microscopy

Microscope Reflection ModeLightpath

The Upper Reflachromat objective projects a conical surface of IR radiation through the sample. It reflects off the shiny metal beneath the sample and follows the same conical surface up through the sample, back to the objective, and from there to the detector.

This mode is very fast and easy to perform. The shiny metal substrate is usually 0.005 inch aluminum sheet taped onto a microscope slide. It is cut from 5 inch by 5 inch sheet that is cheap and disposable. It can also be performed on any flat or curved metal surface such as injection molding tool surfaces, medical steel cannulas, engine valves, gun metal, you name it.

To Detector

From Source

Sampleon metal

Shiny Metal Substrate

Shiny Metal Substrate

>The FTIR Microscope increases greatly the utility of FTIR and allows the successful use of IR in analyses that simply could not be done by a Mainbench alone.

>The Micro - ATR Objective obtains surface spectra (of the top ~micron of material) with almost no sample prep. This is excellent for thin coatings or surface analysis.

>The FTIR Microscope can obtain useful spectra from extremely thin samples as small as a 10μ X 10μ Square. The amount of mass providing such a signal can approach the Detection Limits of GC/MS

>Example - FTIR Microscope’s Limit of Detection is about a 10μ X 10μ Square : If sample is 1μ thick, 10μ X 10μ X 1μ sample of Polyethylene = how many grams? 1cc of PE = 1g = 10mm X 10mm X 10mm = 1000 cubic mm = 103 mm => 10mm X 10mm X 10mm = 104 μ X 104 μ X 104 μ = 1012 cubic microns => So: 1012 cubic microns = 1g

10μ X 10μ X 1μ =100 cubic microns = 102 cubic microns 102 / 1012 = 10-10 g So: 10μ X 10μ X 1μ sample of Polyethylene = 0.0000000001 grams of PE

So, the FTIR Microscope can ID 100 trillionths of a gram of PE

UNIQUE ADVANTAGES OF THE FTIR MICROSCOPEHow sensitive is it? See arithmetic below.

Microscope ATR Mode LightpathThe ATR Reflachromat objective projects a conical surface of IR radiation onto the inside of the ATR Crystal’s Sample Contact Point. A small part of the IR radiation “tunnels” into the sample touching this Contact Point. Some of it is absorbed and the rest continues on to the detector.

This mode is particularly well-suited to surface analysis (surfaces that are bioactive, drug eluting, bioresorbable, coated, “blooming” additives, lubricious, non-thrombogenic, etc.).

It is also a good choice for highly absorbing materials that are difficult to get an IR beam in and out of such as Black Rubber.

From Source

To Detector

Sample Sample

How Small Can Samples Be?How small IS the 10μ X 10μ Limit of Detection?

Back of USA Penny

LincolnMemorial

Lincoln seated on Penny’s back

This image is 11.2mm X 8.5mm.

Lincoln seated on Penny’s back; mm scale to left

This image is 3.0mm X 2.3mm.

IR-Plan Visible Light 10X Objective view (Glass)Lincoln’s Head and Shoulders

This image is 550μ X 420μ

IR-Plan IR Objective 15X Reflachromat view: Lincoln’s Head

This is the magnification at whichKnife-edge apertures are used to frame

the area to be analyzedand FTIR Spectra are obtained.

10μ X 10μ

This image is 390μ x 300μ

Limit ofDetection:

“Lincoln’s “Eye”

Lincoln’s Face on the previous slide is about 140μ X 120μ.The IR-Plan can obtain good spectra from much smaller samples than this (see asbestos ribbon, below). The thin polymer coating on Lincoln’s Face is easily IDdas Polycarbonate.