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ACCESSORIES FOR INFRARED SPECTROSCOPY (FTIR)

Infrared Materials Technical Information
Windows
ATR Prisms
Dies
Polishing Kit
Oil in Water Analysis Kit
Gas Cells
Diamond EX-Press Compression Cell
Universal Sample Holder
The K-Sample Holder
EZ-Chip Sample Holder
Table Press for KBr-Pellets

Infrared Materials Technical Information

Before selecting a transmitting material as window for a cell or ATR prism in infrared spectroscopic application, the following parameters should be taken into consideration — useful transmission range, refractive index, solubility, reactivity and cost. Depending on the application, mechanical and thermal properties of the material may be important. The table below is provided as a selection guide and Medway Optics will not only offer you quality products but experts technical support at value-to-cost ratios among the most competitive in the marketplace.

MaterialUseful Transmission
range (~ 2mm thick)
Refractive
Index @ 5µ m
Solubility in H2O
g/100g @ 20ºC
(cm-1)(µm)

Sodium Chloride (NaCl)40,000-6250.25-161.5236.0
Potassium Bromide (KBr)40,000-3850.25-261.5465.2
Potassium Chloride (KCl)40,000-5000.25-201.4734.7
Caesium Iodide (CsI)33,000-2000.30-501.75160@61ºC
Calcium Fluoride (CaF2)62,500-1,0000.16-101.400.0017
Barium Fluoride (BaF2)50,000-8350.2-121.450.12 @ 25ºC
Thallium Bromoiodide (KRS-5)16,000-2500.6-402.380.05
AMTIR-1 (GeAsSe Glass)11,400-8300.9-122.51Insoluble
Silver Chloride (AgCl)20,800-4000.48-252.00Insoluble
Zinc Selenide (ZnSe)10,000-5251.0-192.41Insoluble
Germanium (Ge)5000-8702.0-11.54.01insoluble
Silicon (Si)**10,000-1001.0-1003.42Insoluble
IR-Fused Silica (SiO2)40,000-2,5000.25-4.01.42 @ 3µminsoluble
Sapphire (Al2O3)3,300-1,8000.30-5.51.60Insoluble
Diamond (C)(synthetic)**45,000-FIR0.22-FIR2.4Insoluble
** Transmission is not continuous. Bands occur between 6-28µm for Si and 4-6µm for C


In pressure applications, the following formulae for calculating window thickness apply for circular windows.
For clamped window:tclamped = 0.866 x D x (P/M)1/2
For unclamped window:tunclamped = 1.05 x D x (P/M)1/2
where:  t = window thicknessD = unsupported diameterP = pressure
            M = modulus of rupture or apparent elastic limit depending on nature of material.
The above formulae has a safety factor of 4.
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1.Windows (all dimensions in mm)

D = Diameter, W = width, L= length, T = thickness

1.1 Unpolished (Blank)Windows

Ordering information
D x T NaClKBrD x T NaClKBrL x W x TNaClKBr

13 x 3W010W03538 x 5W016W04129 x 14 x 5W025W050
19 x 3W011W03638 x 7W017W04230 x 15 x 5W026W051
20 x 3W012W03747 x 6W018W04338 x 19 x 5W027W052
25 x 5W013W03847 x 7W019W04438 x 19 x 6W028W053
25 x 6W014W03950 x 4W020W04541 x 23 x 5W029W054
32 x 4W015W04050 x 6W021W04641 x 23 x 6W030W055

1.2 Polished Windows


General Specification
Flatness*: 3-4 fringes/25mm dia. @633nmClear aperture: ³ 80 of central area
Parallelism: 3-4 arc minutesAngular tolerance: ± 5 arc minutes
Surface finish: 80-50 scratch/dig* KRS-5 and AgCl excepted

Tolerance: D, L, W = ± 0.2mm, T = ± 0.2mm      All dimensions in mm, dr = drilled


Ordering information
D x T NaClKBrKClCaF2BaF2KRS-5ZnSe*AgClAMTIR-1IR-QuartzSapphire*

6 x 1 W100W130W160W190W220--------------------W370W400
13 x 1 W101W131W161W191W221W251W281W311W341W371W401
13 x 2W102W132W162W192W222W252W282W312 W342W372W402
19 x 2W103W133W163W193W223W253W283W313W343W373W403
20 x 2W104W134W164W194W224W254W284W314W344W374W404
25 x 4W105W135W165W195W225W255W285W315W345W375W405
25 x 5W106W136W166W196W226W256-----W316W346W376W406
29.7 x 4.2**---------------W197W227-----W287--------------------
29.7 x 6.1W108W138W168W198W228--------------------------------
32 x 3W109W139W169W199W229W259W289W319W349W379W409
32 x 3drW110W140W170W200W230W260W290W320W350W380W410
32 x 8.5 (step)W111W141W171W201W231-----W291----------W381-----
38 x 4W112W142W172W202W232W262W292W322W352W382W412
38 x 6W113W143W173W203W233W263-----W323-----W383W413
47.5 x 5W114W144W174W204W234W264W294W324W354W384W414
47.5 x 7.5**---------------W205W235-----W295----------W385W415
47.5 x 10W116W146W176W206W236------------------------------
49 x 6W117W147W177W207W237W267W297W327-----W387-----
50 x 3W118W148W178W208W238W268W298-----W358W388W418

L x W x TNaClKBrKClCaF2BaF2KRS-5ZnSe*AgClAMTIR-1IR-QuartzSapphire*

29 x 14 x 4W119W149W179W209W239W269W299--------------------
29 x 14 x 4drW120W150W180W210W240W270W300--------------------
30 x 15 x 4W121W151W181W211W241W271W301W331W361W391W421
30 x 15 x 4drW122W152W182W212W242W272W302W332W362W392W422
38 x 19 x 4W123W153W183W213W243W273W303W333W363W393W423
38 x 19 x 4drW124W154W184W214W244W274W304W334W364W394W424
41 x 23 x 4W125W155W185W215W245W275W305W335W365W395W425
41 x 23 x 4drW126W156W186W216W246W276W306W336W366W396W426
41 x 23 x 5W127W157W187W217W247W277W307W337W367W397W427
41 x 23 x 5drW128W158W188W218W248W278W308W338W368W398W428
50 x 25 x 6W129W159W189W219W249W279---------------W399-----
ZnSe* is offered at 3mm thick or less except where indicates **. Sapphire* is offered at 3mm thick or less.

Other sizes available on request.
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2. ATR Prisms for Infrared Spectroscopy

The criteria for selection of prism material to obtain a good FT-IR ATR spectrum is outlined below. For a good spectrum, it is essential to select conditions to achieve optimum depth of penetration (dp).

  • The useful wavenumber (cm-1)/wavelength (l ) range of the material. The wider the useful transmission wavelength range, the better the material for general purpose uses. The depth of penetration increases with decreasing wavenumber/ increasing wavelength.
  • Refractive index of material (h 1). This determines the critical angle (q c) of the material at which total internal reflection phenomena begins to occur. The higher the material refractive index, the lower the critical angle. It is desirable for the angle of incidence to far exceed the critical angle to avoid spectrum distortion when working with high refractive index (h 2) samples
  • Angle of incidence (q i). Increasing angle of incidence will decrease the depth of penetration and number of reflections. These will decrease effective pathlength and therefore decrease the absorbance intensity of the spectrum
  • Effective sample contact. It is important to achieve a good sample contact all over the ATR prism sample contact area to obtain a good spectrum. In solid samples it is important to choose an ATR material that will permit sufficient pressure to be applied without causing damage to the prism or sample in order to obtain a good spectrum. The hardness of the material is important.
  • Material reactivity. When dealing with liquid samples, careful attention should be paid to solubility in water, the reactivity of the ATR materials to acids, bases, oxidising and reducing agents and complexes.
 l h2  
dp =--------------------------------------q c = sin-1----------
 2p h 1 (sin2 q i - (h 2/h 1)2)1/2  h 1
 
 

N = L/T tan q i
Where N = number of reflections, L = length (centre to centre), T = thickness

Ordering information
Prism Size45º ATR Prism (30º, 60º and other sizes available on request)
L x W x T (mm)KRS-5ZnSeGeSiKRS-5ZnSeGeSi
ParallelogramTrapezoid
50 x 20 x 1A010A030A050A07072 x 10 x 6*A020A040A060A080
50 x 20 x 2A011A031A051A07150 x 20 x 1A021A041A061A081
50 x 20 x 3A012A032A052A07250 x 20 x 2A022A042A062A082
50 x 10 x 1A013A033A053A07350 x 20 x 3A023A043A063A083
50 x 10 x 2A014A034A054A07450 x 10 x 1A024A044A064A084
50 x 10 x 3A015A035A055A07550 x 10 x 2A025A045A065A085
25 x 10 x 2A016A036A056A07650 x 10 x 3A026A046A066A086
25 x 10 x 3A017A037A057A077 
Note:  L is measured tip-to-elbow (or centre-to-centre) except* measured tip-to-tip.
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3. Evacuable Pellet Dies

Technical information
Transmission technique offers one of the most reliable and accurate means of quantitative and qualitative analysis by infrared spectroscopy. Evacuable pellet dies allow small amounts of solid samples blended with suitable infrared transmitting powder medium such as KBr or KCl to be pelleted for transmission analysis. A hydraulic press is required for pelleting.

Medway Optics offers dies with the following features and options:
  • Sample evacuation prior to pressing to remove traces of water vapour that could interfere with sample analysis.
  • Vacuum hardened 440C Stainless Steel parts resistant to scratches and chemical attack from vast majority of laboratory samples.
  • Highly polished Stainless Steel pellets for scatter free and good surface finish samples.
  • Easy removal of sample for analysis and dismantling of die parts for cleaning.
  • Optional tungsten carbide polished pellets for extra hard samples.
  • Optional 15 tons and 25 tons presses for infrared and X-ray fluorescence (XRF) sample pressing applications.

  • Ordering information

    A Die set comprises of body (with black anodised sleeve), base, O-rings (2 off), plunger, one face polished pellets (2 off) and an extractor ring. 3* mm Die set uses one polished pellet and a polished plunger.

    KBr Dies for InfraredXRF Dies for sample cups        
    Die Set Size (mm)3*58101316  253240
    P/ND010D020D030D040D050D060  D070D080D090
     
    PelletsD011D021D031D041D051D061  D071D081D091
    PlungerD012D022D032D042D052D062  D072D082D092
    O-ringsD013D023D033D043D053D063  D073D083D093
    Extractor ringD014D024D034D044D054D064  D074D084D094
    Sample holderD015D025D035D045D055D065  D075D085D095
    Tungsten CarbideOn Request  On Request
    Hydraulic Presses(15 tons)  On Request  (25 tons)  On Request

    P/N D056      13mm KBr Starter Kit comprising of
  • 13mm Die set
  • -P/N D050
  • 100gm KBr powder
  • -P/N D201 
  • Spatula
  • -P/N D202 
  • Tweezers
  • -P/N D203 
  • Disc holder
  • -P/N D204 

    Handpress Evacuable Die set

    Technical information

    This is a low cost but effective way of producing a pellet die for infrared analysis without the use of a hydraulic press. The set comprises of a precision honed stainless steel cylinder body with evacuation tube, two 9/16 UNF hardened stainless steel bolts with optically polished ends with seals, two spanners and a slide die holder. The die set will produce a 8mm diameter pellet inside the cylinder. The sample is trapped inside the body (poured from one end) in between the two bolts. Vacuum is introduced into the chamber through the evacuation tube for a short while and the two bolts are turned against each other to press the sample. The result is a clear pellet formed in the cylinder. The two bolts are removed and the sample in the cylinder is placed on the slide die holder, which locates in the infrared spectrometer for analysis. The sample can be washed away with water after analysis. This Handpress die set is most suitable for teaching laboratories and in industries where the demand for frequent pelleting of samples is low.

    Ordering information
    D210Handpress 8mm Die set comprising of:
    Die body, polished bolts with seals (2 off), spanners (2 off),
    KBr powder (100 gm) and slide die mount
    D211Handpress 8mm Die and polished bolts with seals
    D212Spare polished bolts with seals (2 off)
    D213Spare spanners (2 off)
    D214Spare seals (4 off)
    D201KBr powder (100 gm)
    D215Spare slide Die mount
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    4. Optical Polishing Kit

    Technical information
    This optical polishing kit contains all the accessories needed for buffing and re-polishing soft materials that do not require pitch polishing such as NaCl, KBr and KCl windows for spectroscopic application. Polishing form blank materials will require a bit of skill from grinding, smoothing and polishing but buffing and re-polishing require minimal skill. Polishing from blank also requires a glass optical flat. The kit is not recommended for cleaning KRS-5.

    Ordering information
    O010Optical polishing kit comprising
    Fine grinding/smoothing lap, polishing lap, self adhesive selvyt pads (6 off), 1 bottle coarse abrasive 400 grit, 1 bottle fine abrasive 600 grit, 1 bottle polishing rouge, 1 strip of selvyt cleaning cloth, cleaning brushes (2 off), 1 instruction manual, carry case
    O011Fine grinding/smoothing lap
    O012Polishing lap
    O013Self adhesive selvyt pads (6 off)
    O014Bottle of polishing rouge
    O015Fine abrasive 600 grit
    O016Coarse abrasive 400 grit
    O017Glass optical flat
    O018Selvyt cleaning cloth strips (2 off)
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    5. Oil in Water/Hydrocarbon Analysis kit

    Technical information
    The oil in water analysis kit allows trace amounts of hydrocarbon in water effluents originating from petroleum products such as oil or grease to be analysed by the method certified by the Environmental Protection Agency (EPA) of the United States of America. The kit comprises of one matched pair of 10mm pathlength rectangular cuvette, one matched pair or 50mm pathlength two ports circular cuvette, one matched pair of 100mm pathlength two ports circular cuvette, 1 universal cuvette holder for rectangular and circular cuvettes from 10mm to 100mm pathlength, 1 instruction manual and a carry case. All the cuvettes have round neck stoppers to prevent evaporation, and are made from infrared grade fused quartz.

    Ordering information
    O110Oil in water/hydrocarbon analysis kit
    O111Matched pair if 10mm pathlength rectangular IR Quartz cuvette
    O112Matched pair of 50mm pathlength circular IR quartz cuvette
    O113Matched pair of 100mm pathlength circular IR Quartz cuvette
    O114Universal cuvette holder for 10mm to 10mm pathlength rectangular/circular cuvettes
    Other cuvette holders are available on request
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    6. Gas Cells

        

    Technical information
    Two types of cells for gas analysis are available as standard. Stainless Steel gas cell is made of 316 Stainless Steel suitable for most gas applications. For more corrosive gases, our Teflon gas cell provides an ideal solution. Both are available is 10cm pathlength, and are fitted with leak free easy fit valves for flow or static laboratory applications. The cells are supplied with two tubes with rifle ends for connection to laboratory tubing packaged in a carry case.

    Specification
    Material of body316 SS Stainless SteelTeflon
    End capsBlack anodised aluminiumBlack anodised aluminium
    Vacuum valvesTwo Nupro plug valvesTwo PFA valves
    Window-to-cell sealViton O-ring seal (Nitrile optional)Viton O-ring seal (Nitrile optional)
    Window-to-cap sealTeflonTeflon
    Clear aperture25mm diameter25mm diameter
    Pathlength100mm100mm
    Volume50cc50cc
    Outlet valves connection1/4" (6.35mm) Swagelok1/4" (6.35mm) tubing
    Supplied connectiontwo 1/4" s/s tube with rifle endstwo 1/4" Teflon tubes with rifle ends
    Supplied cell mountSlide holder with cell grip screwSlide holder with cell grip screw

    Ordering information
    G01010cm Stainless Steel gas cell kit without windows
    G01110cm Teflon gas cell kit without windows
    G012Set of Viton O-ring seals (6 off)
    G013Set of Nitrile O-ring seals (6 off)
    G014Set of Teflon seals (6 off)

    Window (pair) for 10cm gas cells
    NaClKBrCaF2BaF2ZnSeSiIR-QuartzSapphire
    G020G021G022G023G024G025G026G027

    Other Common Gas Cell Windows
    D x T NaClKBrKClCaF2BaF2ZnSe*IR-QuartzSapphire*
     
    25 x 4W105W135W165W195W225W285W375W405
    25 x 5W106W136W166W196W226-----W376W406
    29.7 x 4.2**W107----------W197W227W287-----------
    29.7 x 6.1W108W138W168W198W228----------------
    38 x 4W111W141W171W201W231W291W381W411
    38 x 6W112W142W172W202W232-----W382W412
    47.5 x 5W113W143W173W203W233W293-----W413
    47.5 x 7.5**W114W144W174W204W234-----W384-----
    47.5 x 10W115W145W175W205W235---------------
    49 x 6W115W146W176W206W236W296W386-----
    ZnSe* is offered at 3mm thick or less except where indicates **. Sapphire* is offered at 3mm thick or less.

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    7. Diamond EX-Press Compression Cell

    Technical information
    The Diamond EX-Press is an excellent sample preparation tool for FTIR micro analysis. The diamond is a high quality Synthetic Type IIa Sumi-crystal with excellent physical and infrared transmission properties. Samples of solids and film (e.g. mineral stones, polymers and pharmaceutical materials) can be compressed to thin uniform films by using only finger tight pressure for good infrared analysis without prior sample preparation.

    The cell is fitted with 1mm thick diamonds, has a working distance of only 11mm and fitted with a 3" x 2" backplate making it ideal for FTIR spectrometers without a beam condenser and Infrared Microscopes with 15X and 32X objectives.

    Ordering information
    P/N J010
    P/N J011
    Diamond EX-Press Compression Cell 1.6mm diameter clear aperture
    Diamond EX-Press Compression Cell 2.0mm diameter clear aperture
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    8. Universal Sample Holder

    Technical information
    This patented innovative sample holder allows samples of various types (films, Nujol mulls, KBr pellet disc) and sizes from 13mm to 40mm diameter, and up to 13mm thick to be held and analysed by transmittance in infrared spectrometers. The cone shaped clip holder is gimballed and can be turned over for use in the opposite direction for different sample sizes. The spring loaded clip holder sits on an interchangeable magnetic base which gives 10mm or 22mm clear aperture depending on the direction on use.

    Viton O-ring protects the sample from the retaining clip and a thumb screw provides an adjustable pressure on the sample. The holder has a 3" x 2" backplate for easy insertion into all infrared spectrometers.

    Ordering information
    P/N J015Universal Sample Holder
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    9. The K-Sample Holder

    Technical information
    The K Holder is a simple but versatile accessory for holding liquid and solid samples including pellets for analysis in IR, UV, NIR and Raman instruments. The unit consists of an adjustable slide mount with a 2-position sample block attached to a 3" x 2" backplate. The sample block has a V shape on one end that allows circular shaped samples (e.g. discs, pellets, circular cuvettes) to be securely mounted and a flat end on the opposite side for holding flat objects such as cuvette. The two ends are interchangeable.

    Depending on the size and shape of the sample, the slide mount can be adjusted 25mm along the 3" x 2" backplate to position the sample precisely in the 13mm diameter aperture of the backplate and secured tight using a thumb screw.

    Ordering information
    P/N J020K-Sample Holder
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    10. EZ-Clip Sample Holder

    Technical information
    This accessory provides a quick, easy and inexpensive way of mounting window discs, pellets and films for transmission analysis in infrared spectrometers. The samples are held on a 3" x 2" backplate using a spring loaded clip and a Viton O-ring protects samples from the clip. Two sample holder models are available, a 25mm diameter aperture more suitable for windows and films and a 13mm diameter for pellets.

    Ordering information
    P/N J025
    P/N J026
    EZ-Clip Sample Holder with 13mm diameter clear aperture
    EZ-Clip Sample Holder with 25mm diameter clear aperture
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    11. Table Press for KBr-Pellets

    Technical information
    The table press is a compact efficient mini-press designed for laboratories with small budgets but with frequent need of making KBr pellets quickly. It is sturdy on a bench table, with small footprint it occupies minimum space and is easy and safe to use.

    Good KBr pellets are produced in KBr Dies using light press pressure by smooth operation of the press handle effortlessly single handed. It is ideal for making 1mm to 16mm KBr. It is oil free and no maintenance is required.

    Ordering information
    P/N J030Table Press for KBr pellets

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