The 6 Channel 4700 Precision Diluter represents the next generation in accurate canister standards preparation. Utilizing a combination of precise gas flow control, exact pressure measurements, and an ultra-inert flow path, the 4700 is capable of performing multistage dilutions for achieving standards ranging from part-per-billion to low part-per-trillion. The 4700 works with canisters and Bottle-Vacs™ to create dilutions up to 100x, and then allows a second dilution of up to another 100x to yield a total 2 step dilution of up to 10,000x.
With the 4700, small 100L cylinders at 1PPM will allow over 15,000 6L canisters to be filled to atmospheric pressure with a 1PPB mixture by first making a 20PPB working standard that can be further diluted into each canister to be tested. This results in just pennies worth of standard being consumed when performing inertness testing of canisters every 1-2 years. By contrast, typical dynamic diluters that must balance flows and pressures can typically only fill 50–100 6L canisters per high concentration cylinder, making field canister inertness testing prohibitively expensive.
The 4700 uses precise pressure control, rather than mass flow controllers to meter in the standard. This approach has several advantages. First, very little of the standard mix is used in making a standard. This allows the original cylinder to last longer, keeping cylinder pressures higher where contents are more stable. Secondly, the mixing region used in a dynamic diluter is eliminated, substantially reducing surface area and carryover.
Performing US EPA Method TO15
- How are Canisters Filled in the Field?
- Preparing Gas Phase Standards for TO15 GCMS System Calibration
- TO15 Sample Analysis
- Cleaning Canisters for Reuse
Gas Phase Calibration Standards Should be as Similar to Sample Matrix and Concentrations as Possible
Used to calibrate the GCMS response for target compounds, prove linearity, and create method MDLs
For proper method validation, make the standard similar to real samples, at expected concentrations and humidity levels
More Accurate Than Dynamic Dilution Performs 2-10,000 Fold Dilutions!
- Precise pressure measurement of each standard for accurate mass delivery to the receiving canister
- Unlike Dynamic Dilution, a single sensor meters in all gases, cancelling out gain and zero errors
- Always comes with 6 channels fully installed, with a re-dilution channel to make lower level standards.
- Water is added manually to canisters (70ul), which is more accurate than using an online humidifier (4600A/D)
1000x Calibration Range using 4700 Prepared 0.4 PPB and 20PPB Standards
4700 Prepares the 20PPB standard from 1PPM cylinders, then re-dilutes the 20PPB standard further down to 0.4 PPB. The 7200 can take different volumes from each canister to dramatically increase the dynamic range while performing GCMS calibrations and method validations