Model: Waters Alliance 2695 Four Element Pump System
Detailed description: Four element low-pressure gradient system configuration with reverse control, original software, and automatic sampler
Configuration: One set of 2690 quaternary low-pressure pump system, including one set of 2695 quaternary digital pump, one set of 120 position original automatic sampler (with temperature control system), one original online deaerator, one original online plunger cleaning device, one original column temperature box, and one original Agilent data processing system software.
Original factory price: 580000
Discounted price: 160000 yuan
Origin: Waters Corporation, USA
Condition: More than 80% new, as shown in the picture (photographed).

Product Introduction:
Origin: United States
Background of Waters launching Alliance:
In recent years, companies have adopted the same method for liquid chromatography, using essentially unchanged instrument structures to improve their instruments. That's why everyone believes that the performance of liquid chromatography, including accuracy, reliability, and efficiency, has reached its limit.
Today, Waters challenged this view and pushed liquid chromatography in a completely new direction. This direction is inspired by the outlook for the future and innovative technologies. Waters, with over 30 years of achievements in the field of liquid chromatography, is proud to launch a new generation of instruments - the Alliance

2695 separation unit
Organic combination of solvent and sample management process
1. Solvent management system (pump):
A、 Relying on innovative design to fundamentally improve performance
- Newly designed flow path
Advanced high-speed solvent proportional valve
- Independent linear plunger drive device
- Dual pressure sensors
The solvent inlet is located on the front of the plunger
- "Transfer point flow rate optimization" software
- Flow rate accuracy reaches 0.075% RSD
- No need for dampers or gradient mixers, truly reducing system volume
B、 Comparison with traditional HPLC:
Alliance (Alliance)
Two independent linear motors are driven separately without pressure fluctuations, without any dampers or gradient mixers, ensuring a low system volume to ensure the reproducibility and accuracy of gradients
The accumulation plunger delivers most of the solution to the system, while the main plunger mainly transfers the solution to ensure the stability of infusion
Two pressure sensors sense and adjust the pressure inside the plunger, ensuring smooth exchange between the plungers and guaranteeing output without pulsation of the mobile phase
No outlet valve, reducing failure rate

The above points ensure that Alliance's flow rate accuracy has exceeded the accuracy of traditional HPLC, reaching 0.075% RSD, ensuring high accuracy, reproducibility, and precision of analysis results, and ensuring the reproducibility and accuracy of gradients.
Traditional HPLC pump
A motor drives two plunger rods through a transmission device, with pressure fluctuations, and the pressure is stabilized by a damper

Whether it is a series pump or a parallel pump, the two plungers respectively deliver equal amounts of liquid to the chromatographic system
A single pressure sensor only monitors system pressure, and the two plungers cannot exchange smoothly, resulting in pulsation
There is an outlet valve, which is the most faulty component in the pump
2. Sample management system (automatic sampler):
Inheriting the advanced design of Waters sampler, continuously flowing samples
- Five independent 24 position sample trays that can accommodate 120 samples
Each sample tray has a fixed position and can be used for different purposes
- Can operate any sample tray or bottle, which is conducive to the overall arrangement of analysis time
- Excellent linear range and injection reproducibility, injection accuracy<0.5% RSD
- Fully automatic injection needle cleaning device, cleaning the inside and outside of the needle separately to ensure minimal cross contamination and sample contamination<0.5%
- Fully electronic design, requiring no other power besides the power supply

New generation liquid chromatography instrument - Waters Alliance 2695
Technical indicators:

Linear dual plunger drive device with independent control of pump/solvent management system, dual pressure sensor feedback loop, no pulsation, no need for mixer and damper
Number of solvents 4
Flow rate range 0.001-10000ml/min, in increments of 0.001
*Flow velocity accuracy 0.075% RSD
*Flow velocity accuracy ± 1.0%
Operating pressure 0-6000psi (0-410bar)
Compression compensation automatic, continuous
Gradient curves come in various forms: linear, stepwise, convex, and concave
*Gradient mixing reproducibility ≤± 0.15% does not vary with backpressure
*Gradient accuracy ≤± 0.5% does not vary with backpressure
Mixing range 0.0~100.0% in increments of 0.1%
Delay volume<650 μ L, not changing with backpressure
Sample Management System
120 sample trays, 5 sample trays, each tray can hold 24 sample bottles
Injection frequency: 1 to 99 injections per sample
*Injection accuracy<0.5% RSD (full process)
*Sample contamination level<0.1%
Injection accuracy ± 1 uL
Sample bottle 2 mL
*Injection volume 0.1 to 100 uL
*Injection linearity>0.999 coefficient of deviation
2、 Detector:
Waters2487 detector technical specifications:
Noise:<± 0.35 × 10-5AU
Drift: 1 × 10-4AU/h
Linear:<5% at 2.5AU
Bandwidth: 5nm
Wavelength range: 190-700nm
Measurement range: 0.0001-4.0 AUFS