Recent advancements in measuring techniques and detection technologies have dramatically improved the sensitivity of modern analytical instrumentation. Trace elements can now be measured at ppt and sub-ppt levels using techniques such as ICP-MS. These low detection levels allow new applications, such as elemental fingerprinting, to be employed in diverse fields such as forensic science, the food and beverage industry and astrogeology.
Low detection levels mean that special care must be taken with the instrumentation, operators, laboratory environment and any sample containers used — all of which can impact experimental results. This is equally true for ultrapure water used in the analytical process. Due to the dissolution and dilution processes required in sample preparation, high-purity water typically constitutes over 90 % of a sample analyzed by these sensitive techniques. High-purity water is also used for cleaning sample containers, washing plastics, and preparing blanks and standard solutions.
Laboratories performing trace analysis must have a reliable source of ultrapure water with consistently low elemental concentrations. The Q-POD® Element has been designed to achieve this purpose when combined with Milli-Q® Integral or Milli-Q® Advantage A10. ultrapure water system and developed by scientists conversant with trace analysis methods such as IC, ICP-MS and GF-AAS.
Q-POD® Element for ppt and sub-ppt element analysis
The drawing below shows a typical Milli-Q® Integral water purification system installation with a Q-POD® Element unit.
- Milli-Q® Integral water purification system purifies tap water to pure (Type 2) and ultrapure (Type 1) water. Designed for bench integration to save laboratory space; patented Elix® technology minimizes operating costs.
- A polyethylene tank with vent filter combining several air purification technologies provides the best conditions for storage of pure water and minimizes contamination risks.
- E-POD® dispenser for delivery of pure water from the reservoir at a high flow rate (up to 2 L/min), with automatic volume dispense when required — ideal for filling large vessels such as carboys.
- Q-POD® ultrapure water dispenser for critical applications such as HPLC, UPLC or cell culture. A range of Application-Paks is available to match the requirements of specific applications. The Q-POD® design is adapted for automatic filling of all glassware typically used in a laboratory.
- Q-POD® Element unit for the production of ultrapure water suitable for ultra-trace elemental analysis (ppt and sub-ppt detection limits).
- Footswitch for hands-free delivery of water suitable for ultra-trace elemental analysis (spares the user from removing hands from the laminar flow hood environment).
- Delivery of ultrapure water for trace elemental analysis (Plexiglas® support and high-grade validated polyethylene tubing).
Q-POD® Element Validation
In order to verify the quality of water provided by the Q-POD® Element, analytical tests were performed in independent laboratories.
In one laboratory, the tests were performed in parallel, using the new Q-POD® Element unit and the former Milli-Q® Element system. These tests certified that the new design delivers water quality that is equal to or superior to that of the former design, meaning that results formerly obtained with the previous Milli-Q® Element system can be transposed to the new Q-POD® Element unit.
|Values obtained on Perkin Elmer Elan 6100 DRC (Dynamic Reaction Cell).
(*) BEC in ppt or ng/L obtained using Q-POD®Element fed with water produced by a Milli-Q® Integral.
BEC (Background Equivalent Concentration) is calculated as: BEC = Intensity corrected by the background / calibration slope. Calibration slope (obtained from the analysis of 10 standards from 10 ng/l to 500 ng/L (intensity is background corrected)). The background was obtained from signal acquisition without any nebulization of the solution. The obtained limit is an absolute limit: The BEC
(**) For potassium and sodium lower BEC values are obtained with more suitable analytical conditions (such as trace ion chromatography).