212-LC Pump Technology Background August 2006

2 Dual Piston Pump Single piston pumps deliver then refill, forcing the use of a very large pulse damper to keep pressure constant This was the 210 style design Dual piston pumps deliver as the second piston refills, allowing constant pressure with little delay volume This is the 212-LC style design This is better for LC/MS where low pressure pulsations and low delay volume are good for smooth baselines and fast chromatography

3 Self Priming The 212-LC will prime itself with any conventional solvent and at any reasonable flow rate. Turn on the pump and open the integrated purge valve, the pump will prime itself from even a completely dry start. This eases solvent change over and start ups, but has the more significant benefit of the system retaining prime over time, assuring reliable chromatography without the constant re-priming of some pump designs.

4 Self Aligning Pump Seals To maintain superior seal life the seal must remain perfectly aligned with the piston. The 212-LC patented* floating seal design achieves this goal. * US Patent 6,467,395 B2

5 Key Pad Control An easy-to-read LCD display allows the user to monitor several pump parameters such as pressure and flow. Key pad is designed with dedicated, color coded function keys that allow even a new user to turn on the pump and perform basic functions. The 212-LC can be controlled from its own keypad or more seamlessly, from MS Workstation Version 6.6 or higher.

6 Solvent Compressibility Compensation High-Pressure-Mixing binary gradient systems require compensation for solvent compressibility to achieve rigorous flow stability The 212-LC has appropriate compressibility compensation to assure the user reliable and accurate results

7 Easy Maintenance Relatively low levels of preventative maintenance will keep the 212-LC producing results for years to come User serviceable components can be readily accessed from the front panel Varian offers a full range of service plans to keep the system running at its peak performance levels

8 Purge-Prime Valve Assembly Standard on the 212-LC is an integrated front panel valve that permits rapid solvent changes or solvent priming to be done at the pump. Similarly, the pump is supplied with a 150uL mixer that is optimized for 100 to 400uL/min gradient flows. Other mixers are available

9 Varian 212-LC Pump The 212-LC is a gradient capable, binary high pressure mixing system This system is optimised for Varian LC/MS units The two head design is modern and reliable The pump specifications are suited to use with 2 to 4.6 mm analytical column applications

10 Performance Retention Time Precision Good retention time precision is important for many customers – the 212- LC has excellent precision <1% for gradient runs.

11 Performance Compositional Accuracy These tests ( 10% steps) are frequently used to assess accuracy and stability for a gradient pump – additionally delay volume can be assessed. The aim is for sharp, even steps without ripple on the steps – the 212-LC delivers

12 Performance Chromatography Ultimately, the best test of hardware is an application – this test chromatography indicates good gradient performance at low flow rates with short run times – what customers want as a proof statement

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