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Higher sensitivity, robustness, and speed with new 1200 Series variable wavelength detectors
By Christian Gotenfels
Agilent Product Manager for Liquid Chromatography
The analysis of impurities in drug substances and formulations is a challenging application in the drug development process. This requires detection capabilities that allow the simultaneous detection and quantification of a large amount of parent compound and trace levels of impurities. The next generation of Agilent 1200 Series variable wavelength detectors (VWDs) provides a tremendous improvement for this kind of application by delivering significantly lower noise in combination with a wider linear dynamic range, even under harsh and fluctuating ambient temperature and humidity conditions. In addition, the 1200 Series VWD SL Plus with up to 160 Hz data rate is prepared to keep pace with the fastest separations enabled by the Agilent 1200 Series Rapid Resolution LC system.
Higher sensitivity
Due to new optical and electronic components, the baseline noise of the 1200 Series VWD and VWD SL Plus is typically a factor of three to five times lower than the previous model, which translates to a comparable boost to signal-to-noise. Figure 1 shows an example with a signal-to-noise increase of 4.6 for these detectors.
Higher robustness
Providing constant ambient conditions is still a challenge, even in labs with air conditioning systems. Especially for measurement at the detection limits, these fluctuations adversely affect the stability of the detector baseline. To reduce baseline drift, the 1200 Series VWD and VWD SL Plus have built-in electronic temperature control (ETC) for the complete optical unit, which improves the baseline stability by a factor of two to three relative to the previous design.
160 Hz data rate for precise measurement in ultra-fast LC
With peak-widths below 0.4 seconds, the latest ultra-fast LC analyses present the ultimate detection challenges. For best quantification, the detector must be fast enough to sample 20 points across these very narrow LC peaks. If the sampling rate is too low, peaks that are separated in the column become merged in the data acquisition, which leads to a loss of resolution in the chromatogram. Figure 2 shows the importance of detector speed and demonstrates that the Agilent 1200 Series VWD SL Plus, which samples at up to 160 Hz, easily keeps pace with today’s ultra-fast LC analyses.
New levels of data traceability and security
A variety of flow cells are available for the Agilent 1200 Series VWD and VWD SL Plus, so you can choose the one that provides the optimum sensitivity and resolution for your needs. The flow cells have built-in radio-frequency identification (RFID) tags that store information about the cell, such as part number, serial number, production date, cell volume, path length, and maximum pressure. An RFID tag reader in the detector transfers this information directly to the instrument control software.
Similarly, RFID tags for the UV lamps offer the highest levels of data traceability by recording part number, serial number, production date, number of ignitions, total burn time, and the date of the last successful lamp test.
The built-in data recovery card (DRC) provides “data-never-lost insurance” by preventing data losses in the event of communication breakdowns between instrument and PC. Raw and metadata are automatically buffered on an embedded memory card.
For more information and chromatograms that show the performance characteristics of these latest VWDs, see Agilent Technical Note 5989-9721EN.
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