Rheodyne 7725 Stainless Steel Analytical Manual Sample Injectors

How to Choose a Sample Injector  Table I below compares the characteristics of Rheodyne® manual sample injectors and will help you choose the most suitable model. Types and Capabilities Models ending in 25 (i.e. 7725) are dual mode injectors. Dual mode injectors can use both the partial-filling and the complete-filling method for loading the sample loop. They are variable volume injectors because they allow the loading of various sample volumes. These dual mode injectors, also called front-loading injectors, have a needle port for loading sample built into the handle. The unique injection port design allows the tip of the needle to connect directly to the sample loop for no sample loss during loading. Models ending in 10 (i.e. 7010) are single mode injectors. Single mode injectors use only the complete-filling method to load the sample loop. They are called fixed loop injectors as the sample loop size determines the sample volume. These injectors require a Loop Filler Port accessory, as a needle port is not built into the valve handle. There is not a direct connection between the syringe and the sample loop. Therefore, an excess of sample must be used to overfill the Loop Filler Port and completely fill the sample loop. Models with an "i" suffix (i.e. 7725i) are identical to the models with the same numbers but the “i” designates a built-in position sensing switch. The switch provides the chromatograph with a reproducible start signal to mark the injection time in the data system. The reproducibility of manual sample injectors depends on operator skill, syringe calibration, and the loading method. Partial-filling method is typically reproducible to 1.0% relative standard deviation (RSD). Complete-filling method is reproducible to 0.1% RSD for loops 5 µL.		Scale, Sample Volume, and Loop Size Analytical scale models are for conventional columns with samples from 1.0 µL to 5.0 mL. Microscale models are for 1.0 mm and 2.0 mm inner diameter columns. Model 8125 has a sample range of 0.1 µL to 500 µL, and can be used for both analytical and micro columns. Preparative scale models are for columns with diameters from 1 to 10 cm, and operate at high flow rates with samples from 100 µL to 20 mL. Liquid Contact Materials All models have a polymeric rotor seal of Vespel® (pH 0 to 10 tolerance), ETFE or PEEK™ (both pH 0 to 14). Stators are 316 stainless steel or PEEK. Most models have an inert ceramic stator face assembly. Make-Before-Break (MBB®) Models incorporating Rheodyne’s MBB architecture design provide uninterrupted flow when switching between LOAD and INJECT positions. MBB greatly reduces transient pressure shocks and is beneficial for flow-sensitive detectors, fragile columns, and pumps. Models 7725, 9725, 3725, and “i” versions contain the MBB design. Replacement Parts Genuine Rheodyne parts are available for easy maintenance of your Rheodyne valve. RheBuild® Kits offer a complete solution to keep your valve running, providing all necessary parts to rebuild your valve and easy to use step by step instructions to assist you in the process. Rheodyne also offers a complete line of sample loops, fittings, and accessories designed specifically for the Rheodyne valve.
Characteristics of Rheodyne Manual Sample Injectors Type & Capabilities Scale Partial Filling Volumes (Range) Sample Loop Sizes (Range) Wetted Materials Max. psi (bar)1 Max. T (°C) MBB2 Model3 Dual Mode Can load the loop by two methods: 1) Partial filling – syringe determines volume without wasting sample 2) Complete filling – loop determines volume by over filling loop Analytical 1 µL – 2.5 mL 1 µL – 5.0 mL 2 µL – 5.0 mL 2 µL – 10 mL 316 SST, Vespel PEEK, ETFE, ceramic 7,000 (483) 5,000 (340) 80° 50° Yes Yes 7725, 7725i 9725, 9725i Micro 0.1 µL – 500 µL 5 µL – 1.0 mL 316 SST, PEEK, Vespel, ceramic 7,000 (483) 80° No 8125 Preparative 100 µL – 10 mL 2.0 mL – 20 mL 316 SST, PEEK PEEK 5,000 (340) 4,000 (276) 50° 50° Yes Yes 3725(i)-038 3725, 3725i Single Mode Can load the loop by one method: Complete filling – loop determines volume by over filling loop Analytical Not Applicable 5 µL – 5.0 mL 5 µL – 10 mL 316 SST, Vespel PEEK, ETFE, Ceramic 7,000 (483) 5,000 (340) 80° 50° No No 7000 9010 Micro Not Applicable 0.5 µL – 5 µL 0.2 µL – 1 µL 316 SST, Vespel 316 SST, Vespel 7,000 (483) 7,000 (483) 80° 80° No No 7410 7520 SST = Stainless Steel 1 This is the maximum pressure to which the valve can be adjusted. Some models are shipped from the factory set for lower pressures. 2 MBB (Make-Before-Break) is a design that provides uninterrupted flow when switching between LOAD and INJECT. MBB also greatly reduces transient pressure shocks. 3 Models with an "i" suffix have a built-in position sensing switch. Models 8125 and 9010 also have a built-in switch.