Q-Grad Quaternary High Pressure Gradient System

Q-Grad system with stand-alone keypad control. Optional software control is available.

The Q-Grad System provides reproducible high-pressure quaternary gradient capability for HPLC applications. The four high-performance pump heads can be programmed through an independent keypad unit or from optional PC-driven software. The result is high-pressure gradient performance for the price of a low-pressure gradient system.

The Q-Grad system includes an easy-to-use, high sensitivity Model 500 variable UV wavelength detector designed for routine applications. An optional tungsten lamp may be used for applications that require the visible range.

The Q-Grad system includes an intelligent keypad controller for programming and storing gradient methods. This compact unit can also be used to prime individual pump heads and to apply flow rate corrections if necessary. External synchronization from an injector or autosampler may be enabled using the TTL cable that is provided with the accessory kit. Run/Stop inputs and real-time pressure monitoring (with upper and lower pressure limits) are standard features of the Q-Grad software.

Optional PC-based gradient control can also be achieved by standard RS-232 communication using a multi-port interface box via a single serial port of a PC using SSI Q-Grad software. The user-friendly software permits editing of the gradient profile using a graphic gradient editor (GGE) in addition to the use of a standard table.

Close-up of keypad unit back panel

The Q-Grad High-pressure gradient system utilizes a very efficient internal pulse damper mixer to ensure high performance gradients. The internal mixing design of the solvent delivery system eliminates the need for external mixing devices and tubing. A prime-purge valve and electronic pressure transducer are also standard features of Q-Grad. As with all SSI pumps, Q-Grad carries a 3-year warranty, to ensure reliability over time.

Q-GRAD PUMP SPECIFICATIONS
Flow Rates	0.001 - 5.0 mL/min. (each pump head)
Pressure	Stainless Steel: 0 – 6,000 psi PEEK: 0 – 5,000 psi
Pulsation	± 1% @ 1mL/min and 1,000 psi
Pressure Accuracy	± 1% of full scale pressure
Flow Accuracy	± 2%
Flow Precision	0.2% RSD
Voltage	110-120 Vac, 50/60 Hz; or 220-240 Vac, 50-60 Hz
Physical	6.5" H x 12.0" W x 15.5" D (165 x 787 x 394 mm); 42 lbs (19 kg)
STANDARD PUMP FEATURES Self-Flushing Pump Heads Pulse Damper for Reduced Pulsation Motor Stall Detector Prime-Purge Valve Stainless Steel or PEEK Fluid Path Spring Loaded Check Valves STANDARD CONTROLS RS-232 Serial Com Port (each pump) Real Time Pressure Reading Run/stop Input (each pump) - 5 volt TTL type GRADIENT CONTROL Gradient control is achieved via host PC and SSI Q-Grad control software or control unit. Communication from Pump Module to PC is through four RS-232 interface cables. Typical Pump Gradient Percent Range: 0-100% in 0.1% increments. Percents B, C, D programmable; Percent A automatically adjusted. Specifications subject to change without notice. KEYPAD UNIT SPECIFICATIONS FEATURES Indicates current controller status: ‘Idle’; ‘Init’ (Starts Initial conditions); ‘Wait’ (Waits for start of program from injector/autosampler); ‘Run’ (Indicates run is in progress); ‘Pending Requests COM 1234’ (indicates which pumps are not communicating with controller); ‘CL’ (panic abort the current sequence/run); ‘0’ (abort current run); ‘MODE’ key switches between status screen and gradient program options; Use down arrows to scroll through parameters and gradient table screen. PARAMETERS AVAILABLE FOR EDITING Flow Rate; Delay Time (Time for return to initial conditions at end of run); Equilibrium Time; Low Pressure Limit; High Pressure Limit Gradient step: Time, %A, %B, %C, %D (to one decimal place)
MODEL 500 DETECTOR SPECIFICATIONS
Range	UV, 190-360 nm (deuterium lamp) Visible, 360-800 nm (optional tungsten lamp)
Monochromator	Holographic grating
Bandwidth	6 nm
Wavelength Accuracy	±1 nm (Mechanical drive)
Wavelength Reproducibility	±0.1 nm
Noise	±1 x 10-5 AU, typical
Drift	2 x 10-4 AU/hr.
Absorbance range	0.0005 to 2.0 AUFS (12 range settings)
Integrator outputs	1 V/AU
Recorder outputs (Full scale)	10 mV, 100 mV, 1V
Rise times	0.025, 0.1, 0.3, 1.0, or 3.0 seconds
Dimensions	9.75" (24.8 cm) W x 6.25" (16.6 cm) H x 13.25" (33.7 cm) L
Weight	20 lbs. (9.1 kg)
Power	100, 110, 220/240 Vac; 50/60 Hz; 125 W