A CE-based analytical system configured optimally for the quality assurance laboratory. With a focus on repetitive robust analyses, the system includes a P/ACE MDQ configured with a filter-based UV/Vis (200, 214, 254 and 280 nm included) detector, UV source optics, ambient sample storage module, large volume buffer reservoirs, and 32 Karat™ Software configured on an IBM personal computer. Installation Qualification, Operation Qualification 1 (OQ1) and documentation to aid in software validation is also included.
Capillary Thermoregulation with Recirculating Liquid Coolant
Recirculating liquid coolants dissipate "excess" heat much more effectively than air-cooled systems. Efficient heat dissipation is critical in capillary electrophoresis to allow for the usage of higher conductivity buffers and larger I.D. capillaries. Your benefit is more flexibility in sample load and the ability to create better separation efficiencies with the use of higher ionic strength buffers. This allows methods to be easily transferred from a methods development laboratory to a routine use environment.
Multi-format Sample Introduction
Automation is certainly a means by which many laboratory bottle necks may be reduced. The use of 96 well plates as a sampling vessel not only increases system capacity but allows compatibility with automated sample preparation devices which utilize the 96 well plate format. Additionally, 2 ml vials (which are autosampler industry standards) may be used; or sampling can be achieved directly from PCR vials and microfuge tubes.
High Sensitivity UV Detector
Detector sensitivity in capillary electrophoresis is critical since small mass loads are introduced and small detection pathlengths are used (governed by the capillary dimensions i.e. 25 - 200 um). Fixed wavelength detection in a filter wheel assembly maximizes detector sensitivity yet still allows wavelength changes during a run. In a Q.C. or regulated environment it is beneficial to "lock-down" a method once it is developed in order to retain the integrity of the data. The P/ACE™ MDQ high sensitivity UV detector may be configured with a "single" wavelength from a filter traceable to NIST making both the instrument certification and method validation much simpler. Additionally the system employs complete fiber-optic technology bypassing the necessity of an optical bench. This lowers the noise on the detection system (by removing reflective surfaces where energy loss can occur) and simplifies the system making it more rugged for routine use. Diode array is an essential detection tool for methods development work, but will reduce the lifetime of a "coated" capillary. Therefore, once a method is developed and is in routine use it is beneficial to switch to a UV detector where the capillaries will last longer.
Multiple Separation Modes
Voltage gradient programming is beneficial for gel-sieving techniques improving separations over a wide range of fragment sizes. This is especially critical for the separation of nucleic acids. The application of simultaneous voltage and pressure is beneficial for the high efficiency mobilization of proteins during iso-electric focusing as well as detecting material not migrated off the capillary. Also, several CEC methods have specified the use of simultaneous pressure applied to both inlet and outlet reservoir. This system is compatible with those methods.
Automatic Standards Co-Injection
Sample injections can be automatically spiked with reference standards for positioning or for positive identification. This is useful to help minimize errors resulting from sample matrix effects. Additionally, with high salt samples it may be necessary to do multiple injections within the same run in order to employ an electrokinetic salt elution step. Practical examples of this include the electrokinetic injection of PCR samples directly after amplification. The interfering salts and metals would need to be be removed through a sample handling step if one were not able to perform an electrokinetic elution from ddH20 prior to sample introduction. Additionally, once a sample table has begun the data that is generated may indicate the necessity to run new sample combinations. On the fly sample table editing may be accomplished with the 32 Karat Software allowing the addition of new samples to a running sequence.
Large Volume Buffer Reservoirs
When a method is validated for routine use, one's need changes away from buffer type scouting to buffer capacity as a large number of samples are processed using a single condition. With P/ACE™ MDQ, the buffer array and reservoirs are interchangeable. Each buffer reservoir contains two 30 ml chambers for the inlet and outlet buffer and ten 2 ml vial positions for conditioning fluids. The large volume reservoir allows hundreds of runs to be facilitated from a single buffer tray alleviating the need to frequently change buffers.
Electrokinetic, Pressure and Vacuum
Sample Introduction In moving validated methods from a development lab to a routine use environment, the issue of compatibility of methods transfer is always present. The P/ACE™ MDQ is designed to operate with all commonly used sample introduction modes and has the capability to dial in the parameters (i.e. injection pressure or vacuum), allowing greater ease in transferring methods between instrument brands. Being able to inject from the short side of the capillary, offers the capability of high speed separations.
Fluid Delivery with Variable Pressure and Vacuum
Conditioning of the capillaries is accomplished by moving specific volumes of electrolytes, regenerants and cleaning solutions through the capillary. The P/ACE™ MDQ is designed to operate with all commonly used rinsing protocols and the capability to regulate these parameters (i.e. magnitude of applied pressure or vacuum), allows greater ease in transferring methods.
GLP/CGMP Compliance Features
Many laboratories are mandated by law to follow current good manufacturing practices (CGMP) and good laboratory practices (GLP) The 32 Karat Software has many features which are geared towards the maintenance of data integrity. Sample data and methods parameters cannot be overwritten or overridden, ensuring the data that was generated was as described. To track instrument operation, all events including errors are logged onto the system. To provide security of operation users may be coded to different security levels with selected access to: system configuration, methods programming, data reprocessing, specific instrument operation and data comparison. All of these features can be used to "lock down" the system for regulated use.
Specialized CE Calculations
Capillary electrophoresis requires specialized data handling. Mobility calculations establish the identity of a compound independent from changes in electroosmotic flow, voltage, temperature and column dimensions. This can be very useful in compound identification and method validation especially when comparing data between different laboratories where analytical conditions may vary slightly. While normalizing the peak area to analyte velocity is important if quantitation is required. Intelligent system suitability, allows unattended operation for routine use environments.