1. Reaction Monitoring with the ReactionView® System
Remspec Corporation
© Remspec Corp. 2007

2. Remspec Corporation
Remspec has been manufacturing and selling mid-IR fiber optic systems since 1993 (fourteen years).
We have sold over 200 fiber-optic probes and systems to academic and industrial customers all over the world.
We have more experience with mid-IR fiber optics than any other company.
Our software is designed by synthetic chemists to be used by chemists, and is written by in-house software staff. We can provide fully customized software.
Our experienced scientific staff provides full support for applications development.
Remspec has a lot of experience with building mid-IR fiber optic systems, but our competitors have been selling fiber optics for only a few years.
Remspec has synthetic chemists on the staff to answer questions about using our products in the lab., and about the best way to interpret the results.
© Remspec Corp. 2007

3. ReactionView® Compact FTIR, 35 lb, 1- ft2 footprint
Range cm-1
ATR and transmission heads fit wide range of reactors
Full control and display software on a laptop
20 hr detector dewar for overnight experiments
The connection to the laptop is by Ethernet.
The probe in this picture is a high-temperature probe. It is shown in a glass reaction tube with a B24 ground glass joint.
Remspec systems are modular and the heads can be interchanged for different applications.
© Remspec Corp. 2007

4. ReactionView-4
The four-channel version of ReactionView allows four probes to be used at once on one spectrometer.
Ideal for use with parallel reactor arrays.
We can provide a system with four probes, but it is better for the customer to buy a single probe, then upgrade to the four-probe system if they need it.
When more than one probe is used, our software provides independent control of each one.
© Remspec Corp. 2007

5. Modular Systems Remspec systems are fully modular
Sampling heads for high or low temperature, high pressure, corrosive solvents
Replaceable ATR crystals for standard conditions, high and low pH, corrosive conditions
Transmission head for very low concentrations
Only the head is changed for changing conditions or different types of reactor port
One of the big advantages of the Remspec system is the modular design. This means that parts can be replaced or repaired without the need to buy a whole new system.
ATR crystals are less than a thousand euros and can be replaced by the user if they are broken. When the user wants to change to a different reactor where there are special requirements they only need to buy a new head.
© Remspec Corp. 2007

6. Mid-IR Probes with interchangeable heads
Liquid
transmission
head
The probe has 19 fibers in it. Seven take the signal from the spectrometer to the sample, and twelve go from the sample to the detector. They are combined into one bundle in the shaft of the probe, which is 6 mm in diameter.
Our fiber bundle design provides maximum optical throughput (better signal to noise performance) as well as better mechanical performance (smaller diameter fiber gives smaller bend radius).
Fiber-optic probe with cables
ATR head (with ZnSe crystal)‏
© Remspec Corp. 2007

7. ATR Head A range of materials can be used (ZnSe is shown)‏
Good, general-purpose probe
Sensitive down to about 0.1 wt.% of most analytes
Works in all solvents, including water
Stainless steel* probe, shaft graphite-filled Teflon® seals, and inert crystal materials make the probe corrosion-resistant.
ATR: ZnSe, ZnS, Ge, Si, AMTIR, KRS-5, CdTe, diamond, and ZrO2 are all available.
This ATR crystal is a 2-bounce design. We also use crystals with flat tips that have 3 bounces for applications such as skin chemistry. The ATR method is explained later in the presentation.
*Hastelloy is available for extreme conditions
© Remspec Corp. 2007

8. Transmission Head
The Liquid Transmission Head lowers the detection limit to <0.1mM.
It is a double-pass transmission cell with a mirror wall.
It can only be used in solvents that have low mid- IR absorbance (e.g. hexane,acetonitrile, methylene chloride, THF); suspended solids can interfere with performance.
The transmission cell has an adjustable path from – 10 mm. It is adjusted by turning the screw at the end of the head to move the mirror surface.
Note in the picture that there are no raised edges on the mirror or the crystal to capture bubbles
Our competitors do not have transmission heads.
An example is given later of using a transmission head to track the formation of a low-concentration intermediate (the ketene example).
© Remspec Corp. 2007

9. Sampling Heads: High Temperatures
High Temperature Head
Gas cooled (air or nitrogen)‏
ATR or Transmission
-100ºC to >200ºC
15mm OD
Available with chemically resistant polymer end for low heat transfer
Head fits onto a standard probe.
Temps to >200° C, or down below -100°C.
This is our “general purpose” head, with the widest range of use. For temperatures over 120 C a chiller is required for cooling the cooling gas
© Remspec Corp. 2007

10. In-Situ Spectroscopy at High Pressures
High Pressure Head
Custom HIP style (tapered cone) or 1/2” Dynisco fittings
P > 200 bar
ATR or Transmission
Gas cooled (air or nitrogen), -100ºC to >200ºC
Head is fitted onto standard probe.
Temps to >200° C, pressures to 200 bar (one customer took the head to 300 bar without loss of pressure).
We will provide the appropriate pressure fitting for customer's reactor (e.g. Dynisco, HIP, custom).
© Remspec Corp. 2007

11. What is ATR? Attenuated Total Reflectance
ATR crystal, or Internal Reflectance Element (IRE)‏
Effect depends on differences in refractive index
We use ATR heads for most of our probes. The next four slides explain how the ATR effect works, and some differences between the 2- and 3-bounce heads.
Mettler uses a thin, flat ATR crystal with more bounces and they claim that it is more sensitive. Our ATR heads are easier to use and cheaper to replace if they are damaged
© Remspec Corp. 2007

12. What is ATR?
When the wave is reflected from the interface between the crystal and the sample, it travels a short distance into the sample – this is called the evanescent wave.
© Remspec Corp. 2007

13. ATR Design: Variation of Penetration Depth with Incident Angle
Approximate penetration depth at each bounce
is given by the expression:
 = wavelength of the radiation,
np = refractive index of the crystal,
= angle of incidence of the light beam, and
nsp = ratio of refractive indices of sample and crystal.
Think of penetration depth as the same as the path length of a transmission cell
This equation shows how the depth of penetration of the evanescent wave into the sample depends on the refractive index of the crystal and the sample and the angle of the bounce.
© Remspec Corp. 2007

14. Do more bounces mean better signal?
The red line 3 bounce is less sensitive than the blue line 2 bounce.
The blue line is 2 45 degree bounces whereas the red line is 1 45 and deg bounces.
This is all in accord with theory. The penetration depth is nonlinear with angle so one 45 has a greater penetration than two 22.5 deg bounces.
Therefor two bounces give better performance than three bounces so.
2 bounce versus 3 bounce
© Remspec Corp. 2007

15. What about Diamond?
Available for extreme conditions, but not recommended
Expensive
Large blind spot at 2000 cm-1
Graph is signal v's wavenumber
This is best quality type IIA diamond
The blind spot is not so bad with Mettler but it is still there
The blue line is the diamond, the red line is a ZnSe crystal on the same cables
Mettler uses diamond or silicon ATR crystals
© Remspec Corp. 2007

16. ATR Design for Calibration
Bundle Fiberoptic ATR (Remspec)‏
Angular distribution of light entering the ATR crystal is always the same.
Thin Film ATR (Mettler)‏
Incident angles change when framework is moved or the head is removed and replaced
Errors multiplied by multiple bounces
A sensitivity adjustment is required (Contrast adjustment)‏
This means that the calibration of a thin film ATR will change when any adjustment is made. The Remspec ATR does not have this problem.
© Remspec Corp. 2007

17. Calibration: Mid-IR Spectrum of Phenyl Isocyanate in Acetone
The next few slides show a very simple illustration of calibration transfer. You can't do this with Mettler rigid conduit systems because the sensitivity changes when you move the conduit. Mettler fiber is better but we have been told if you disconnect the fiber conduit and reconnect it the results change
© Remspec Corp. 2007

18. Calibration: Curve Fitting of 2200-2380 cm-1 Region in
Mid-IR Spectrum of Phenyl Isocyanate
The characteristic isocyanate peak is shouldered, so a peak fit is carried out to get good absorbance numbers.
2261 cm-1is used for the calibration graphs.
The VizIR software allows the user to run this kind of peak-fitting calibration automatically during the reaction.
2283 cm-1
2261 cm-1
© Remspec Corp. 2007

19. Phenyl Isocyanate in Acetone
Probe 1 gives a linear calibration.
© Remspec Corp. 2007

20. Phenyl Isocyanate in Acetone
When probe 2 is used, the results fit the calibration that was created using probe 1.
© Remspec Corp. 2007

21. VizIR™ Software
Can collect a single dataset for 3.5 days at one spectrum per minute (5000 spectra)‏
VizIR includes a Control Panel for setting the resolution and timing of data collection during an experiment, as well as Start and Stop buttons.
The display windows show a 3D picture of the spectra versus time, and a window for most recent spectra or trend-lines.
The VizIR software is very easy to use and it gives displays that are useful for reaction monitoring, because it was designed to be used by chemists.
The 3D display can be rotated and repositioned so that changes and trends in the data can be picked up quickly by eye.
The lower display shows the five most recent spectra, overlaid.
© Remspec Corp. 2007

22. VizIR Software
Trend lines can be set up by eye using the Peak- Picker utility, by typing in a desired wavelength, or by using peak fitting (useful for resolving overlapping peaks).
Both products and reactants can be followed.
The lower display has been changed to show absorbance/time trendlines for selected peaks.
These displays are all updated in real time.
© Remspec Corp. 2007

23. VizIR-Remote™ Software
When a VizIR experiment is running, the VizIR- Remote Java applet can be used to view the results in real time across a computer network.
VizIR-Remote can also be used to compare spectra and trend lines from different channels – in this case, the mid-IR and Raman spectra from the same reactor.
A Java applet is available so that the results can be viewed remotely over a local network.
This means that you can track the reaction from your desk.
© Remspec Corp. 2007

24. ReactionSleuth™ Software
Simple trendlines, baseline corrected lines and ratios of lines.
Peakfit modeling using multiple peak curve deconvolution and fitting of groups of peaks.
Post processing using PCA/Target Transformation (similar to ConcIRT) for “model free” data analysis
Saved Methods
ReactionSleuth is used to analyze data after the reaction is finished.
The Principal Components Analysis (PCA) identifies features that change as the reaction progresses.
The Iterative Target Transform calculates “synthetic spectra” from the data.
This method is useful if reliable simple trendlines cannot be calculated because the data is too complex.
© Remspec Corp. 2007

25. ReactionSleuth Software
Plots of individual PCA factors and their scores (loadings)‏
The Principal Components are not spectra, they are a mathematical constructs that look like spectra, sometimes with negative features.
© Remspec Corp. 2007

26. ReactionSleuth Software
Target transformed “synthetic spectra” and their loadings.
In favourable cases, the synthetic spectra are similar to the real spectra of starting materials and products. This type of calculation is not always needed to analyze a dataset.
ReactionSleuth is similar to the Mettler ConcIRT software, but with some additional features. ReactionSleuth gives the user more control over the calculation and more diagnostics to understand what the math is doing than ConcIRT does.
© Remspec Corp. 2007

27. ReactionSleuth Software
Raw data with synthetic spectra subtracted.
This can be useful for identifying side reactions and intermediates.
When the synthetic spectra are subtracted, the 3D display of the residuals will sometimes show features that have been overlooked.
© Remspec Corp. 2007

28. Example: Crystallisation of a Polymorphic Material
Although Remspec mid-IR ATR spectra usually “see” only the solution phase, it is sometimes possible to observe crystallisation when the crystals form against the ATR surface.
High thermal conductivity crystals such as Diamond or Si can easily become fouled (coated with crystals)‏
In this example, a crystallization is being studied.
This compound can crystallize in different polymorphs.
© Remspec Corp. 2007

29. Example: 2-step Organic Synthesis
2-step commercial synthesis reaction
Step 1
Anion formation
Step 2
Product formation
Solvent is DMF
Note solvent peak at approx cm-1.
In this example, we do not know the details of the reaction, which was carried out at the lab of a commercial customer.
© Remspec Corp. 2007

30. Example: 2-step Organic Synthesis
ReactionSleuth™ can be used to calculate “synthetic spectra” using a PCA/Target Transform technique.
A set of three synthetic spectra is shown here, with the “loading” curve for each, showing the changes in the contribution of each synthetic spectrum to the data set over time.
The synthetic spectrum shown in the main window is almost identical to the spectrum of DMF, which was used as the solvent
The changes in absorbance during the reaction are due to dilution as reactant solutions are added.

31. Example: 2-step Organic Synthesis
The 3D display shown here is the result after one of the three synthetic spectra has been subtracted from the data set.
The subtracted spectrum (shown in blue on the next slide) closely resembles the mid-IR spectrum of the DMF solvent.
Each synthetic spectrum in turn can be subtracted from the 3D display.
In this case, the solvent has been subtracted.

32. Example: 2-step Organic Synthesis
The upper, blue, trace is a synthetic spectrum that closely resembles that of DMF.
The second, green, trace is a synthetic spectrum that appears and disappears during the reaction, so we have extracted the spectrum of an intermediate and its time/concentration behaviour.
The third, red, synthetic spectrum, can be identified as the product.
Here are the three synthetic spectra calculated from this dataset.

33. Example: Formation of Ketene Intermediate
ReactionView was
used with a
low-temperature
liquid transmission
head to monitor
a low-temperature
reaction at very
low concentrations in a small reactor.
Preparation of a ketene intermediate from acetyl chloride by HCl elimination.
The probe was placed in a very small reactor (25 ml) at a low temp. (-25 C) and low concentration (sub-mmol).
The transmission head was used because of the very low concentrations.
Methylene chloride was the solvent.
© Remspec Corp. 2007

34. Example: Formation of Ketene Intermediate
Hunig's base (0.05 mmoles) in methylene chloride (8 ml)‏
Acetyl chloride (0.25 mmoles) in methylene chloride (2 ml) added incrementally [approx. 50 μl every 30 minutes]
One increment gives an acetyl chloride concentration of 0.78 millimolar in the reaction mixture
CH3COCl CH2=C=O [ketene]
The ketene product cannot be isolated for analysis. A real-time spectroscopic probe is the only way to measure it.
Eliminate HCl
© Remspec Corp. 2007

35. Example: Formation of Ketene Intermediate
The “fingerprint” region of the spectrum includes peaks from the starting material (acetyl chloride) and the intermediate product (ketene).
The peak at 1806cm-1 is from the starting material (acetyl chloride) and it disappears.
The peak at 2134 cm-1 is from the ketene product and it grows.
© Remspec Corp. 2007

36. Example: Formation of Ketene Intermediate
The real-time display in VizIR shows the increase in the acetyl chloride peak when it is added, followed by the increase in ketene as the acetyl chloride is consumed.
This is a screen shot from VizIR during the reaction
The red trendline is from the acetyl chloride, and the blue one is from the ketene. The ketene is unstable and decomposes during the reaction.
© Remspec Corp. 2007

37. Fermentation Monitoring
Cloudy, aqueous medium with varying optical density
ATR in the mid-IR samples only the liquid phase and is not affected by suspended solids or varying optical density
This example is a simple fermentation of sucrose using baker's yeast.
© Remspec Corp. 2007

38. Fermentation Monitoring Carbon dioxide region
A single peak emerging at 2342 cm-1 is characteristic of dissolved CO2, and a robust calibration has been developed.
The neighboring peaks are associated with other forms of CO2, e.g. contained in small bubbles; these features are hard to calibrate.
The dissolved carbon dioxide concentration can be tracked directly using mid-IR.
© Remspec Corp. 2007

39. Fermentation Monitoring Carbon dioxide region
The calibration is based on a peak-fitting model of the CO2 spectral region.
VizIR can run the model in real time as spectra are collected, to generate a trendline.
The peak at 2342 cm-1 can be calibrated against known dissolved CO2 concentrations.
VizIR can use a previous calibration to give the CO2 concentration in ppm.
© Remspec Corp. 2007

40. Fermentation Monitoring Carbon dioxide region
The changes in the CO2 region are clearly visible in the 3D display.
The blue CO2 trendline is based on the peak at 2342 cm-1 from the peak-fit model
Compare with the simple line based on the intensity at 2342cm-1.
This is a case where the trend is much more accurate when the peak-fit model is used to eliminate the influence of extraneous factors.
© Remspec Corp. 2007

41. Fermentation Monitoring Calibration of Trendlines
PLS models based on a set of solutions of sucrose, fructose, and glucose, and ethanol can be run in real time.
Note that these trendlines are individually autoscaled.
VizIR can run previously created PLS models to give the concentration of the sugars. It is difficult to track the sugars using simple peak heights.
PLS is partial least squares, a chemometric (statistical mathematical) technique based on the same mathematics as data mining.
© Remspec Corp. 2007

42. ReactionView Spectra of Oxidative Oil Degradation
ReactionView dataset from cm- 1(a baseline correction has been applied to each spectrum).
Shows changes between reaction time min. and 800 min.
Note emergence of feature centered at approx cm-1, the carbonyl region.
This was a very slow degradation reaction run for several days.
Only the last few hours of data are shown.
The reaction was an oxidative degradation of hydrocarbon oil; the exact details are not known.
© Remspec Corp. 2007

43. ReactionView Spectra of Oxidative Oil Degradation
The emerging carbonyl feature is quite complex.
The VizIR software that runs ReactionView can be used to set up trendlines based on peak-fitting models.
This region of the spectra shows carbonyl-containing functional groups, i.e. degradation products.
© Remspec Corp. 2007

44. Peak-Fit Model of ReactionView Data
Model is based on the final spectrum in the set.
VizIR calculates trendlines by fitting the model against each spectrum in the set, either in realtime or in post- processing.
A peakfit model can be built for a dataset while the reaction is still running and being monitored.
After the model is saved, it is run automatically against each spectrum to give a calculated peak height.
The method is particularly useful for features such as this where several peaks overlap.
© Remspec Corp. 2007

45. Trendlines from Oil Degradation Spectra
The peak areas from the model of the carbonyl region are graphed against time (in minutes).
It is possible to distinguish different times of onset, and different rates of emergence for different peaks.
The peaks at and 1736 cm-1 grows more rapidly that the others.
The trendlines that are calculated in VizIR can be saved and imported into a spreadsheet.
These four lines are based on a peakfit model.

46. Synthetic Spectra Calculated from Oil Degradation Data
When Remspec's ReactionSleuth software is used to calculate “synthetic spectra” from the dataset, the two spectra shown in blue and green are obtained.
The red trace is the spectrum from the end of the ReactionView run.
Here, the synthetic spectra are compared with a single real spectrum from the end of the reaction.
© Remspec Corp. 2007

47. Trendlines Calculated for Synthetic Spectra
The two synthetic spectra show different trending behavior.
This confirms the conclusion from the peak- fit trends that two distinct processes are taking place at different rates, and at different induction times.
Process 1: starts around 680 minutes, relatively fast.
Process 2: starts around 700 minutes, relatively slow.
The scores for each synthetic spectrum can be saved and loaded into a spreadsheet, too.
This confirms that there are two different processes going on, exhibiting different kinetics.
© Remspec Corp. 2007

48. In Summary
Remspec manufactures and supplies mature, well supported systems with a wide choice of sampling options that are easy to use and provide repeatable data.
Remspec provides specialized software that is optimized specifically for reaction monitoring and the analysis of reaction data.
© Remspec Corp. 2007
© Remspec Corp. 2007