Adam M. Fermier

Rudimentary capillary-electrode alignment for capillary electrophoresis with electrochemical detection.

A capillary-electrode holder was constructed for electrochemical detection in capillary electrophoresis (CE). The device allows for positioning of the working electrode at the end of the capillary column without the aid of micropositioners or microscopes. The design facilitates the exchange of electrodes and capillaries without the need of refabricating the entire capillary-electrode setup. The system can be assembled in a very short period of time. Alignment with the self-guided system proved to be reproducible for the electrodes used (carbon, nickel, copper). The advantages of reduced downtime and low cost, make the device very attractive for the routine analysis of electroactive species by CE with electrochemical detection.

Very high pressure HPLC with 1 mm id columns

Theoretical calculations and experimental data indicate that very high pressure HPLC can be performed using 1 and 1.5 mm id columns, and contrary to previous beliefs, the frictional heating generated does not appear to be detrimental to the separation.

Comparing cyclodextrin derivatives as chiral selectors for enantiomeric separation in capillary electrophoresis

A total of 26 different cyclodextrin (CD) derivatives with different functional groups and degrees of substitution were tested against 35 basic pharmaceutical compounds in an effort to investigate their effectiveness as chiral selectors for enantiomeric separation in capillary electrophoresis (CE). Testing was performed under the same conditions using a low pH buffer (25 mM phosphate buffer at pH approximately 2.5). Five CD derivatives, namely, highly sulfated-beta-CD, highly sulfated-beta-CD, hydroxypropyl-beta-CD (degree of substitution approximately 1), heptakis-(2,6-O-dimethyl)-beta-CD, and heptakis(2,3,6-O-trimethyl)-beta-CD were identified to be most effective for enantiomeric separations and have a wide range of enantiomeric selectivity towards the model compounds. Over 90% of the model compounds were enantiomerically resolved with the five identified CD derivatives, at a minimum resolution of 0.5. An additional 20 compounds were also tested to demonstrate the validity of the identified CD derivatives. The five CD derivatives were recommended as the starting chiral selectors in developing enantiomeric separation methods by CE.

Powder dispensing robot for sample preparation

An automated powder dispensing station capable of transferring milligram quantities (1-100 mg) of powder for sample preparation was developed and integrated into a commercial robotic workstation (Zymark Prelude). The systems performance was optimized with respect to vacuum flow rate and powder transfer tube cross sectional area, and shown to possess excellent powder dispensing accuracy (RSD = < or = 0.1% for target weights < or = 15 mg) and precision (RSD = 3.43%) for a vanillin sample. Using the commercial features of the Zymark Prelude workstation (liquid handling, weighing, and vortexing/mixing) and the custom powder dispensing station, multiple sets of analytical calibration standards were prepared and subsequently analyzed by FIA in order to assess the systems robustness for sample preparation.

Automation of Chemical Reaction Kinetics and Product Distribution Studies in Pharmaceutical Development

An automated instrument was designed and constructed to facilitate the performance of pharmaceutical degradation studies. A brief theoretical background on degradation kinetics is given to rationalize the design of the instrument and representative data are provided to illustrate its successful application. This system was found to be capable of conducting multiple simultaneous isothermal and nonisothermal kinetic studies with user-defined temperature profiles, sampling periods, and data logging.

Incorporating Automation in Undergraduate Laboratories

Automated techniques and philosophies, which have become increasingly important in modern laboratories, are not traditionally covered in undergraduate chemistry curricula. To this end, we have been incorporating automated sample preparation methods using standard robotic workstations in our undergraduate analytical chemistry laboratory. Using a Benchmate™ II Workstation, an automated method has been developed and implemented for the solid phase extraction of capsaicins from commercial hot pepper sauces prior to liquid chromatographic analysis. This paper reports on pedagogical aspects of incorporating automation into the undergraduate curriculum as well as results obtained for manual and automated extractions conducted by students.