Northeast Regional
Chromatography
Discussion Group
Spring 2007 Meeting

April 26, 2007 MEETING

Summary of Accepted Papers

Presenter Title Affiliation
Todd D. Maloney 

Very High-Pressure Liquid Chromatography-Mass Spectrometry for Method Development and Impurity Identification in Pharmaceutical Analysis

Pfizer Global Research and Development, Ann Arbor, MIS

Essentially every drug on the market or being developed is analyzed by high-performance liquid chromatography (HPLC). Although rugged and robust, HPLC is often criticized as being the rate limiting step in drug development where high-throughput analysis and high efficiency separations are in demand. Reducing the particle diameter (dp) of the packing material in liquid chromatography is the time proven method to achieve increased separation power through faster analysis times and higher separation efficiency. Recently, advances in instrument and column technology have made it feasible to perform very high-pressure liquid chromatography (VHPLC) utilizing small particle (< 2µm) columns for routine analysis. The increased efficiency and resolution from the small particles will ultimately yield faster method development and higher throughput, and provide further cost reduction through standardization of analytical methodologies. This could potentially lead to a truly generic separation system where only small selectivity values will be required to separate structurally similar compounds.

We have investigated VHPLC-MS for routine use in pharmaceutical analysis. We have investigated the performance of chromatographic columns tailored for VHPLC as well as characterized instrument performance. Our presentation will focus on the performance of the instrument for routine method development and discussion of practical considerations for widespread implementation of VHPLC-MS.


Troy D. Wood
Detection of Gluten Exorphins B4 and B5 in Human Plasma by LC-MS/MS

University at Buffalo, The State University of New York, Buffalo, NY

Peptides derived from digestion of wheat gluten, called exorphins, have been previously detected in urine samples from autistic subjects. Because of their opioid activity, they have been suggested by some as playing a role in the etiology of autism. Previous LC-MS results from our laboratories indicated that exorphins degrade rapidly in biological fluids in the absence of the protease inhibitor aprotinin. Here, we show that two of the exorphins, B4 and B5, can be detected in blood plasma samples of patients diagnosed with celiac disease (i.e. high intestinal permeability) using LC-MS/MS. Experiments were performed on a Thermo Electron Orbitrap mass spectrometer. The presence of exorphins in the plasma was monitored from samples collected up to 2 hrs. after the consumption of a pizza ("Pizza Test") by the subjects. The exorphins were detected in three of four test subjects by LC-MS/MS; MS/MS spectra prove conclusively that the peptides are indeed exorphins. This is the first time exorphins have been detected in blood plasma samples.

Diana S. Aga
Characterization of Glutathione Conjugation by Pharmaceuticals Contaminants Using Liquid Chromatography/ Ion Trap Mass Spectrometry

University at Buffalo, The State University of New York, Buffalo, NY

Soil contamination with non-metabolized antibiotics is an emerging environmental concern, especially on agricultural croplands that receive animal manure as fertilizer. In vitro conjugation reactions showed that glutathione s-transferases (GST) induced in maize catalyzed the conjugation of glutathione (GSH) with chlortetracycline (CTC), producing stable conjugates that were structurally characterized using liquid chromatography (LC) with ion-trap mass spectrometry (IT-MS). The chromatogram of the GST-catalyzed reactions displayed two characteristic features of the putative CTC-GSH conjugate: 1) the conjugate eluted sooner than CTC and 2) the conjugate eluted in multiple peaks. The removal of chlorine and the addition of a glutathione moeity result in a highly water soluble CTC-GSH conjugate, thus a much shorter retention time relative to the more hydrophobic CTC is expected. Several fragmentation patterns in the mass spectrum of the CTC-GSH conjugate can be used to verify the identity of the enzyme reaction product. The expected molecular ion [M+H]+ of CTC-GSH conjugate (m/z 751) with chlorine removal was not observed in the positive electrospray ionization. Instead, a base peak of m/z 677, corresponding to the loss of glycine (MW=75 Da) was observed. When m/z 677 was isolated in the ion trap and subjected to further fragmentation, characteristic peaks corresponding to the loss of glutamic acid (m/z=129) and water (m/z 18) were observed in the MS/MS spectrum. Other pharmaceutical-GSH conjugates were characterized by LC/MS and results will be included in the presentation.

Hans F. Schmitthenner and Robert Saccente Micro-Prep LC and LC-MS of Imaging Materials

Eastman Kodak Company, Rochester, NY

To facilitate the isolation of peaks from analytical LC or LC-MS, we have developed a technique for automating the collection of separated components in analytical LC or LC-MS and call this procedure +IBw-micro-prep LC or LC-MS+IB0-. Micro-prep on the analytical scale introduces unique challenges, which include issues focused on timing, collection, and fraction verification. With the ability to run 50 to 100 sequential unattended runs (or more) during working hours (or overnight) it is possible to isolate quantities of material sufficient for mass spec infusion experiments and NMR experiments including various 2-D 1H and 13C spectra. This presentation will illustrate how we used this technique to solve characterization challenges in the area of imaging materials including inkjet (IJ), organic light-emitting diode (OLED), and optical molecular imaging (OMI).
Joseph Fox Applications of a Novel Hybrid LCMS Ion Trap Time of Flight Mass Spectrometer in Small Molecule Identification and Metabolite Analysis Shimadzu
This talk will focus on application of a novel hybrid LC-ion trap, time of flight mass spectrometer to several significant problems in the fields of chemistry and biochemistry.  We will review the identification of unknown small molecule compounds – including both natural products and synthetic pharmaceuticals - via a novel formula prediction software that includes both MSn fragmentation data, as well as high mass accuracy, to yield formula identifications of unknown compounds.  In addition, we will describe the use of the LCMS-IT-TOF to accelerate metabolite identification, without compromising the information needed for characterization.  Here we have considered an open strategy in metabolite detection that integrates the high mass accuracy MSn analysis of the instrument with advanced data filters to find both “expected” and “unexpected” molecules.  We will conclude with a brief description of the advantages of this type of instrument in coupling with novel LC methodologies, including UFLC (Ultra Fast Liquid Chromatography), for fast and accurate compound analyses in complex samples and high-throughput environments.

 

Jason A. Anspach Advancements in Packing Technologies for HPLC Columns Phenomenex

In the early days of HPLC, much as was the case with GC, scientists performing the experiments were expected to pack their own columns.  As the technology progressed, scientists have come to rely on commercially packed HPLC columns to meet their separation needs.  As HPLC has matured the performance, reliability, and lifetime of the columns expectations   increased.
           
One area of recent development in HPLC columns is the implementation of ever decreasing particle sizes.  Several commercial manufactures offer columns packed with materials that are smaller than 3 µm in diameter.  These columns provide an increased number of theoretical plates per unit length allowing the analyst to decrease their overall column lengths, thereby decreasing the analysis times, without sacrificing the overall separation power of the columns.  There are two drawbacks, however, to the use of smaller packing materials.  The first drawback is the pressure required to operate these columns is significantly higher. .  Furthermore, the inner diameters of these columns are significantly reduced, leading to lower peak volumes and subsequently lower tolerances for band broadening or peak dispersion.  The higher backpressure and smaller dispersion requirements lead to columns needing a more homogeneous bed that must tolerate significantly high operational pressures. 
           
Another area of column inadequacy has been for short preparative columns, typically used to purify combinatorial libraries.  During the traditional slurry packing process, the column must be depressurized in order to be fitted with the column end fitting.  Because of their large inner diameter (21.2 – 50 mm i.d.) and short lengths (50-100 mm) the amount of wall support in these columns to retain the packed bed is significantly decreased.  The decrease in wall support leads to a phenomena where a section of the packed bed extrudes from the column while it is removed from the packing reservoir to install the end fitting.  The media extrusion subsequently decreases the packing density in the column, and subsequently reduces the column lifetime. 
           
In this presentation we will outline packing technologies that address the problems in these two areas of column technology.  We will demonstrate that by optimizing the packing process using a 2.5 µm material, columns efficiencies are obtained that are comparable to columns packed with sub 2 µm materials that operate at significantly lower backpressures.  This lower backpressure allows these highly efficient columns to operate on a wide variety of HPLC instrumentation, not just newer higher pressure HPLC instrumentation.  We will also show a revolutionary packing process to pack preparative columns, where the pressure that is applied to the column during packing is never released, which significantly increases the packing density, and therefore the column efficiency and lifetime are improved.  Both column-packing techniques raise the performance, reliability and ruggedness of the HPLC column to meet the scientist’s needs.


Jeannette Karczmarski Achieving High Definition in Complex Mixture Analysis with SYNAPT “High Definition” MS/IMS/MS, with MSE and TAP Fragmentation Waters Corporation

The presentation will focus on application of a unique quadrupole-ion mobility-TOF mass spectrometer for the analysis of a complex biological samples, such as drug metabolite ID in biological matrices, intact proteins, protein complexes, protein conformations, Top-Down protein sequencing, and structural identification using MS/IMS/MS analysis.  
The talk will explain how this instrument leverages the proven benefits of ion mobility to combine fast gas-phase separations with the high resolution and mass accuracy of TOF MS to provide an additional dimension of separation, and enabling the analysis of samples differentiated by size, shape, charge, as well as accurate mass.  Some typical mobility experiments will be used to demonstrate how MS/IMS/MS delivers specificity beyond that achievable by conventional mass spectrometers.
We will also highlight more empowering features of the system including the Driftscope and TriWAVE technology, MSE, and TAP fragmentation and how these features, combined with Ultra-performance liquid chromatography, are being used to deliver the highest level of definition in sample analysis.  The following will be provided:

1) Explanations of UPLC/MSE as a novel “data independent” method for obtaining molecular and structural information for every detectable component in an LC separation and,
2) How the deconvolution function in MSE can provide an alternative to “perfect” chromatography
3) The utility of the Driftscope display for both data processing and performing selective background subtraction.
4) The power of incorporating Time-Aligned-Parallel fragmentation for solving complex structural elucidation problems.
           
We will conclude the presentation by describing how the T-Wave technology within our MS instrumentation has been specifically engineered to couple with Ultra Performance LC systems (ACQUITY and nanoACQUITY) to maximize overall system performance then review how this combined system can improve productivity and enhance scientific discovery. 


Tamara Marchincin Utilizing Temperature to Achieve HPLC Separations on Various Columns  Eastman Kodak Company
The interest in the use of temperature as a tool to enhance separations has increased. In our analytical laboratories at Eastman Kodak Company, we have investigated the role that temperature can play in our separations. This presentation will show the gains achieved by both increasing and decreasing temperature. The improvements discussed will include enhanced separations, sharper peak shape, and resolution gains. The implementation of sub-2 micron particles with temperature increase will also be discussed.

Randall Clouette and Matt Clabaugh Use of LC/MS/MS  for the forensic determination of drugs of misuse Applied Biosystems Inc., Foster City, CA

Typically, the forensic determination of drugs of abuse or misuse has been done by an assortment of analytical techniques.  These techniques include Gas Chromatography (GC), High Pressure Liquid Chromatography (HPLC), and Gas Chromatography Mass Spectrometry (GC/MS).  With the introduction of high pressure liquid chromatography tandem mass spectrometry (HPLC/MS/MS) it has become routinely possible to decrease sample size, improve reliability, decrease detection limits and increase laboratory through-put. 

This work describes the development and use of HPLC/MS/MS as an analytical technique to determine the concentrations of multiple drugs of abuse or misuse in human urine samples as a means of detecting the diversion of misused pharmaceuticals from retail pharmacy stores. The initial screening for these drugs consisted of the monitoring a single transition (SRM) of precursor ion to product ion and comparison to established retention time.  Initial positive screens were subjected to repeat testing using multiple reaction monitoring (MRM) to monitor the transitions from the precursor ion to two product ions and comparison to established retention time.  Limits of detection and upper limits of linearity were established relative to an industry established cutoff value.  Some of the potential interferences and associated instrumental expenses are also investigated.


Lee Marotta Sample Introduction Techniques in Gas Chromatography:  Which technique is most appropriate for my sample type PerkinElmer LAS, Shelton, CT

Gas Chromatography is a very useful tool to the analytical laboratory.  Not only does it provide universal and selective information with the choice of its many detectors, gas chromatography offers the ability to provide information of analytes in many sample matrices taking advantage of its various sample introduction techniques.

Using such techniques, the chemist can enjoy the ability of reporting solutions with ease of use, with enhanced efficiency and robustness,  with improved detection limits and with excellent precision and accuracy.

This presentation will discuss which technique is appropriate to the sample matrix and to the carbon range being investigated.  The techniques will be headspace, thermal desorption, purge and trap, split, splitless and solvent purge injections.  Applications of various different types of samples, typically with MS detection, will be discussed.


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