Description
Specifications Table
Product Name – Whatman Grade QM-H Quartz Microfibre Filter
Quantity/Pack Size – 37MM (Pack of 50), 47MM (Pack of 50), 50MM (Pack of 50), 90MM (Pack of 50), 150MM (Pack of 50)
Form – Circular discs
Grade – QM-H (Quartz Microfibre, High-Purity)
Application – Gravimetric analysis, high-temperature filtration, airborne particulate collection
Product Overview
Whatman Grade QM-H Quartz Microfibre Filters are engineered for demanding laboratory applications requiring ultra-pure filtration media. Composed of 99.9% silicon dioxide (SiO?), these binder-free filters deliver exceptional chemical resistance and thermal stability, withstanding temperatures up to 1000?C without degradation. The quartz microfibre structure provides high particle retention efficiency (0.6 ?m nominal) while maintaining fast flow rates, making them ideal for gravimetric analysis where precision and consistency are critical. Unlike cellulose-based filters, QM-H filters exhibit negligible moisture absorption (?0.02% at 25?C/50% RH), ensuring accurate weight measurements in analytical procedures. Their inert nature eliminates leachables or extractables, preventing sample contamination in sensitive applications such as airborne particulate monitoring or stack emissions testing. The smooth surface minimizes particle bounce-off, enhancing collection efficiency for fine particulates. Available in multiple diameters (37mm to 150mm), these filters are compatible with standard filtration apparatus. Each batch undergoes rigorous quality control to meet ASTM D2986-95 standards for ashless filter papers, guaranteeing reproducibility in critical research and industrial testing environments.
FAQs
1. What is the maximum operating temperature for Whatman QM-H filters?
These quartz microfibre filters can withstand continuous operation at temperatures up to 1000?C without structural degradation or chemical changes, making them suitable for high-temperature ashing procedures.
2. How does the QM-H grade compare to Whatman QMA filters?
The QM-H grade offers higher purity (99.9% SiO?) and slightly finer particle retention (0.6 ?m vs. 0.8 ?m in QMA) while maintaining similar thermal stability. QM-H is preferred for applications requiring ultra-low background interference.
3. Can these filters be used with acidic or alkaline solutions?
Yes, the chemically inert quartz composition resists attack from most acids (except hydrofluoric acid) and alkalis, including concentrated sulfuric acid and sodium hydroxide solutions, without compromising integrity.
4. What is the typical pressure drop across a QM-H filter?
At a face velocity of 10 cm/sec, the initial pressure drop is approximately 1.5 kPa for a 47mm diameter filter, though this varies with particle loading and filter diameter.
5. Are these filters suitable for EPA Method 5 particulate sampling?
The QM-H grade meets the physical and chemical requirements for EPA Method 5 stack emissions testing when used with appropriate sampling trains, offering low artifact formation during high-temperature operation.
