Measuring reaction rates.

 

To the left is one of our Rapid mixing apparatus prototypes.  This apparatus is designed for measuring chemical or biochemical reaction kinetics.  The prototype drives two syringes that mix reactants which are introduced to a flow cell for spectral analysis.  We have built prototypes with one or two motors.   Prototypes use servo controlled valves to route solution from reservoir to syringes or from syringes to flow cell.

 

To the right is a photo showing an early Z-geometry flow cell.  Solution enters and leaves through standard 1/4" x 28  fittings.  UV-vis absorance is monitored using commercial fiber optic spectrometer and optics.

 

 

 

Fluorescence detection.

 

We are working to develop hardware for fluorescence detection in our kinetic measurements.  The photo to the lower right shows a 365 nm wavelenght UV LED and supporting electronics.  To the left of this is a photo demonstrating fluorescence of rhodium b using this LED as an ilumination source.

 

 

 

 

An optical reflector milled using a low cost CNC router.

 

To the right and left are photos documenting our efforts to mill optical reflectors from aluminum bar.  We built a low cost CNC router from a kit (C-Beam Machine, OpenBuilds) and wrote g-code to mill a parabolic reflector.  The reflector was rough cut from 1" x 3/4" aluminum bar using a 1/8" square end mill to give the photo on the right.  It was fine cut using a 1/4" ball end mill.  After milling, the reflective surface was wet sanded to 1000 grit and pollished with aluminum polish, giving the photo on the left.

 

This reflector will be used to focus light from our UV LED into our fluorescence cell.  It can be seen in the background of the photo demonstrating fluorescence (above left).

 

 

 

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WHAT'S UP?

CURRENT PROJECTs

 

August 2020:

  Work during summer 2020 focused on the WheeTrometer spectrometer and on the WheeStat potentiostat.

  The spectrometer is coming along.  We are currently working to improve the intensity resolution by adopting a high resolution analog to digital converter.

  Our work on the WheeStat is focused mostly on increasing the current output available.  In addition, we hope to increase the range of frequencies that can be obtained by adding a digital to analog converter.

August, 2017:

   Work during summer 2017 focused on two projects, the WheeStat potentiostat and the stopped flow spectrometry apparatus.

  •    Work on the WheeStat included changes to the user interface, firmware and hardware.  The newest version of the user interface, WheeStat6.0c, has a new zoom feature and a few bugs from the older interface have been fixed.  We believe the new hardware will be out by the end of 2017.  The new hardware will have an improved method for turning off applied voltatage between experiments.  This is a hardware fix that requires modification of the firmware as well.  We will offer an add-on for our earlier hardware versions that incorporates this feature.  Addditional changes include increased current ranges and the potential for significantly increased scan rates.

  • Work on the stopped flow spectrometry project focused on increasing the injection speed.  Our initial effort focused on developing a rack and pinnion drive for the syringes.  This improved injection speed relative to the lead screw drive but failed to meet target speeds due, we believe, to limited torque provided by the small NEMA 17 motors we chose.  Our next attempt employed larger NEMA 23 motors.  These have significantly higher torque.  Unfortunately, our flow cell was unable to contain the generated pressure and began leaking.  Current efforts are focused on developing a lab-built UV-vis cell that will hold higher pressures.

 

September, 2016:

  • Our work to automate solid phase synthesis of peptides / DNA, etc has progressed well, although the chemistry is more involved that I had origianally thought.  We have made our first attempt at synthesis of a cystiene modified tri-peptide

  • Our application for recognition by the IRS as tax exempt under 501(c)3 has been approved.

  • We have begun work on a low cost visible spectrometer that will use home built reflective optics.

  • We are working on developing a stopped flow kinetics instrument based on commercially avialable spectrometer.  Our current prototype is able to acquire spectra within 120 ms of mixing.  This dead time appears to be limited by the power of the motors we used.  We are investigating the use of larger motors and hope to get the dead time down to below 12 ms.

 

EVENTs

6-10

PITTCON CONFERENCE & EXPO 2016

 

Presentation  in Atlanta, GA,  March 6-10, 2016

Our talk was well recieved at the Educational symposium at PittCon

CONTACT

4989 Tilley Creek Road

Cullowhee, NC 28723

Tel: 828-293-7781
 

 

Mail:  summers@wcu.edu

j6summers@gmail.com

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21

2016 SE REGIONAL ACS MEETING

Oct 23-27, SouthEast Regional Meeting of the American Chemical Society, Columbia SC

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