Calibration of Membrane Filter: Ensuring Accuracy and Precision

At Analytical Chemists, Inc., we specialize in Gas & Air Quality Analysis, therefore the calibration of membrane filters are a critical process to ensure reliable air quality analysis and precise measurement of contaminants. Below is an overview of the techniques, tools, and standards we employ to maintain the highest calibration accuracy.

Gas Chromatography (GC) Techniques

Our analytical processes leverage advanced Gas Chromatography (GC) methods, including:

• GC/FID (Flame Ionization Detector)
• GC/MFID (Micro Flame Ionization Detector)
• GC/TCD (Thermal Conductivity Detector)
• GC/HID (Helium Ionization Detector)
• GC/MS (Mass Spectrometry)

Key Calibration Protocols:

1. We use NIST-traceable gas or liquid standards for all GC methods.
2. Each technique employs 2–6 calibration standards to generate a calibration plot.
3. Calibration plots are developed during every analytical queue.
4. A quality assurance (QA) check standard is run in duplicate for validation.

Analytical Balance Calibration

To measure particulate and oil mist, we utilize a highly sensitive analytical balance:

• Pre- and Post-Sampling Weighing: Filters are weighed before and after air sampling to determine mass accurately.
• Calibration Process:
  • Internal calibration weight validation.
  • External calibration with two weights: 1.0000 grams and 10.0000 grams.

Oil Mist Analysis

Our methods for detecting oil mist range from trace to ultra-trace levels:

• Ordinary Oil Mist: Measured down to 0.3 mg/m³ using gravimetry.
• Ultra-Trace Oil Mist: Measured down to 0.005 mg/m³ using extraction and GC techniques.
• Calibration Standards: Due to the lack of a universal oil mist standard, we utilize three levels of Chemlube 751 for calibration.

Sampling Kit Calibration

Air sampling for oil mist and particulate relies on the precise calibration of flow rates:

1. Airflow Determination: Based on back pressure at the membrane filter and the duration of airflow.
2. Pressure Gauge Calibration: Flow calibrated with a Gilmont #13 rotameter across a range of 2–20 SCFM (used range: 4–19 SCFM).
3. Calibration Plot: Attached to validate the flow measurement accuracy.

Accreditation and Proficiency

• AIHA Accreditation: Certified by the American Industrial Hygiene Association for compressed air analysis (Certification #102116).
• NAVSEA Approval: Approved by the U.S. Navy (NAVSEA) for life support gas analysis.
• C.A.P.T. Membership:
  • Participation in quarterly double-blind proficiency testing.
  • Proficiency testing includes Oxygen, Carbon Monoxide, Carbon Dioxide, Methane, TVHC, and Ethane.
  • Average proficiency score: 97–101% or higher.

Calibration Data Summary

Below is an example of calibration data from a Dedicated SCUBA Sampler (Model P-1033):

Specialized Compound Analysis

Why Choose Analytical Chemists, Inc.?

With decades of experience, our team delivers unmatched expertise in the air quality analysis. Whether for SCUBA, industrial, or life-support applications, we ensure precision and reliability in every test.

📧 Email Us: info@airanalysis.com
📞 Call Us: (888) 724-7522

Location:
7553 Convoy Court, San Diego, CA 92111

For more details on our services or to discuss your specific needs, contact Analytical Chemists, Inc. today!