ProStar 210/218 Solvent Delivery Modules

ProStar 210/215 Solvent Delivery Modules For ALL applications (analytical to prep) Variety of pump head materials & configurations ProStar 210/215 Solvent Delivery Modules

Available Pumps The is a picture of the ProStar 210/218 series. The new pump is smaller in width, longer and slightly Taller. It is the same width as the old 9012 and can stack with either of the new detector as well as the Autosampler. The key pad is slightly smaller but it contains all of the keys that are on the present system. (the ~ key has been replaced with a key with the name SETUP.) An easily removable door fits over the hydraulics on the right side. When the door is one, the system looks very sleek and modern. With the door off, all of the hydraulics are easy to get at. The pressure transducer is installed on the right side of the pump, In addition, the mixer is installed in the same bay as the pressure module on the right side of the 2nd pump when two pumps or more are used. The old SD-200 is now the ProStar 210 and the SD-300 is the ProStar 215

Major features Two, three or four pump gradients Different sizes for different flow rates Different materials Optional piston wash Different pressure ratings (dependent on pump type) This is a similar lsit of the major features for the 210 and 215 pumps.

ProStar 210/215 Pumps Hydraulic design System configurations Electrical connections and signals Other capabilities User interface Product specifications

Hydraulic Design Ball and seat check valve Pulled open by partial vacuum in the pump head (Need to degas pre-mixed solvents) Seal closed by pump forward stroke Removable cartridge for easy replacement

Pump head Max flow Min flow 5 mL 10 µL 10 mL 10 µL 25 mL 25 µL

Pump Head Materials Stainless steel Good for most general applications Titanium Better for high salt content applications, superior corrosion resistance Perceived better for biological applications More expensive, includes piston wash Peek Better for high salt content applications Perceived best for Life Science applications More expensive, + piston wash. Limited pressure

Pump Head Feature Piston wash Either Holds liquid (water) or rigged for constant recycle Back of Piston is rinsed automatically when it moves back- and-forth in the water Only on some pump heads Useful when using salt mobile phases Perceived by customers as always good More expensive

Pump Head Wash head Standard head

Pump Heads 10WS 10SS Wash head Standard head

Pump head Programmable re-fill time 100 msec to 1 sec Faster gives less pulsations Slower gives less possibility of Priming Issues with viscous mobile phases

Pressure limits SS and TI PEEK Head (mL/min) (psi) 5 0.01-5 8700 n/a 210 218 SS and TI PEEK Head (mL/min) (psi) 5 0.01-5 8700 n/a 10 0.01-10 4000 25 0.025-25 4600 6000 50 0.05-50 2000 100 0.1-100 1200 200 0.2-200 3500

Pressure module with pulse damper Flow rate dependent 10, 50,100 and 200 mL/min Monitors pressures for PMIN and PMAX calculations Monitors pressures for compressibility compensation Enter 2 parameters for any solvent Corrects flow rate on the piston’s initial forward movement Teflon Membrane Design with Hexane offering damping resistance Different sizes for different flow rates Enter 2 parameters for any solvent (X, compressibility factor & L, high pressure constant)

Transducer Pulse Damper Design Lock Nut Transducer Body NEVER OPEN A PRESURE MODULE – why? -> There is hexane inside this module. Hexane amount is calibrated. If opened, hexane will leak and pressure will no longer be accurate. Teflon membrane Cap

Binary and Ternary Gradient Systems Two or three pumps, high pressure proportioning + high pressure mixing Can be a mixture of 210/218 pumps Can be different pump heads but the flow will be limited to the smallest head Only need ONE pressure module/pulse damper Advantage of high pressure mixing is the smaller dead volume after mixing. Low presssure mixing avoids a lot of mixing abnormalities.

Ternary gradient hydraulics Injector valve Pump A Tee Column Pump B Mixer Detector Pump C Back pressure regulator

Flow Accuracy Flow accuracy specification +/- 1% of set flow +/- 0.05% of maximum flow Measured %RSD =0.35% Absolute flow can be adjusted using compressibility compensation The specifications and performance of the 210 and 218 pumps were carefully evaluated. Flow accuracy is one of the 2 customer performance specs. Flow accuracy is usually not terribly important as a constant reproducible flow is what provides good retention time and peak area reproducibility. However, with a 2 pump gradient system, flow accuracy provides compositional accuracy. Compositional accuracy is very important for good repeatable separations. The 210 and 218 are speced at +/-1% RSD of the set flow rate. The second half of the spec refers to using the pump at very low flow rates. For example, for the 100 mL head, the best flow accuracy is +/-0.05% of 100 mL/min or =/- 50 microliters per minute. Indeed, experiments run at the limits of this pump heads performance, (e.g. 500 Microliters per minute) yielded the flow rates that were in error 30 uL/min. When flow accuracy was measured for the 210 and 215, it varied +/- 0.35% RSD. This was true for all of the flow rates in the middle of the pump head range. Note that the compressibility compensation can be adjusted on the pump to adjust the actual flow rate to the set flow rate at any pressure. The X term can be raised to give a higher flow rate or lowered to give a lower flow rate. The accuracy was measured by weighing the water pumped during a standard length of time.

Flow precision Flow precision +/- 0.1% RSD Measured isocratic 0.045% RSD overall 0.02% RSD best 8 consecutive runs Measured gradient 0.1% RSD overall 0.04% RSD best 8 consecutive runs Flow precision is extremely important for good HPLC but is it very difficult to measure. Flow precision provides reproducible retention times for better peak identification and reproducible peak areas for better peak quantitation. It is difficult to measure because it is usually measured using an HPLC separation and many things can go wrong with an HPLC separation. Column problems, sparging of mixed mobile phases, changes in room temperature among other things, can all contribute to a lack of measured precision. Tests for flow precision have to be very carefully done. When these tests were carefully carried out, an isocratic reproducibility of 0.04% RSD for a set of 35 consecutive runs was obtained. The best 8 consecutive runs gave 0.02% RSD. This meets the +/-0.1% specification. This was done using the Varian test mix and a Microsorb MV C18 column with 60% ACN and 40% Water. However, before this number was finally achieved, many sources of error in the entire system, (AutoSampler column, mobile phase etc.) had to be removed. You or your customer can achieve these values also but they may take a lot of careful work. Gradient retention time reproducibility is not speced and is a combination of both flow precision and flow accuracy. It was initially done without a really carefully put together system so better number may be attainable. This was done with a 5 minute ioscratic hold at 20% ACN followed by a 10 minute gradient to 80% ACN. Gradient precision can be improved using a longer isocratic hold and a faster gradient.

Gradient delay and accuracy This is the same program as found in the 9012 pump performance challenge. The programmed gradient is dark while the actual trace obtained is shown in a thinner line.

Gradient linearity -100% Gradient linearity runs were done from both 0 to 100% and 0 to10%. The 0 to 100 % has a small dip in the curve at about 60% but it is not clear why.

Gradient linearity - 10% The 0 to 10 % gradient is excellent.

Proportioning accuracy and precision Precision - 0.3% to 0.03% absolute Accuracy - 0.5% absolute - usually on the step from 0% These tests were done several times and the precision of proportioning ranged from 0.3% to 0.03% absolute. (For example, on the step from 0 to 10%, the pump may only make it to 9.7% - 0.3% absolute error.) This is excellent especially for a multi-pump gradient. The accuracy was also measured and the worst step was usually the step from 0% to 10 or 1% with an inaccuracy as much as 0.5%. It is not unexpected that a multi-pump system has poorer performance on the low % proportioning, especially when one pump is starting. Usually it is better to have a customer program the pumps from 10 to 90% rather than 0 to 100 %.

Proportioning accuracy and precision 1% steps The same test was done using 15 steps from 0% to 10% at 1 mL/min.

Proportioning accuracy and precision 10% steps Proportioning accuracy was also measured. This is water vs water with 0.5% acetone. The flow was 1 mL/min and 10% steps from 0 to 100% were programmed at 5 minute intervals. A reverse gradient was also run from 100 to 0%. This was run with 5 mL heads and a 0.6 mL mixer and 2 ProStar 210 pumps.

Isocratic precision This is an example of 7 consecutive runs done during the isocratic precision test and displayed through interactive graphics on the Star workstation. The first peak is a combination of the solvent front and resorcinol. The second peak is naphthalene and the third peak is anthracene. The detector was a 9050 and the AutoSampler was an AI-200. The data was taken on the Star workstation .

Mixers Dynamic mixer Always needed for 210 and 218 to keep composition mixed efficiently Built into 210 and 218. Turns on when pump is turned on. Dual Chamber, dual elements rotating opposite of each other. “T” mixer used for ternary gradient systems before dynamic mixer

Gradient delay and accuracy - results Gradient delay - ( mixer delay) 0.55 mL Mixer flush out (mixer flush out) 2.22 mL From the above plot, the mixer delay for the 0.6 mL mixer can be calculated. The gradient delay is 0.55 mL (there is some laminar flow occurring in the mixer.) The mixer flush out is about 2.2 mL to 99% flushed. The damper flush-out is not important for chromatographic performance because the pressure module, damper is located upstream of where the gradient is formed.

User interface 2 line display Numeric keypad Unique Features Negative times Single point control for multi-pump and UV detector Advised to use controller Control 320 UV detector

Back Panel

Electrical Connections Outputs 3 contact closures Injection mark Time programmed mark + 5 volts Analog out Solvent composition Flow Pressure Wavelength Control of 320

Electrical Connections Inputs Stop (Stop pump and method) Hold (stop method, keep pump running) One 22-bit ADC for data handling in Star Workstation

Other features Flow programming 100 method - unlimited lines Built in automation Failure operation - shut down method Control of units for pressure display (Mpa, psi, Bar) Solvent compressibility compensation Single point control of gradient

Problems Worn Seals Dirty Check Valves Un-primed pump Bad fittings --------------------------------- High Pressure Fluctuating Pressure Low Flow Communications problems Customer chemistry Customer chemistry is often forgotten about as it is assumed that the customer knows what they are doing. Good example is the wavy baseline at the rhythm of the pump strokes. This can be related to mixing issues. We overcome this by increasing the mixer volume or by convincing the customer to mix there mobile phases slightly with one another (5% of one 95% of the other). The other possibility is a slight loss of prime. This can be overcome by using new seals, maybe a different type, Ceramic check valves as they seem to stick less in high organics than the standard ones (ruby ball). Again, trying to convince the customer to mix there mobile phases slightly with one another (5% of one 95% of the other), will also help this.