Air Analysis Standards
When it comes to air quality testing, whether in a lab, workplace, or the environment, precision, reproducibility, and compliance with regulatory standards are critical. The GERSTEL Internal Standard and Dry Purge (ISDP) module helps scientists meet these requirements by enhancing air analysis workflows and data quality.Â
By seamlessly integrating into the GERSTEL TD 3.5+ and TD Core systems, the ISDP adds critical functionality for automated internal standard addition and dry purging of sorbent tubes. These capabilities not only simplify workflows but also improve accuracy and help meet the demands of methods like US EPA TO-17.
What is the ISDP?
The Internal Standard and Dry Purge (ISDP) module is a dual-function module for GERSTEL thermal desorption systems. It performs two essential tasks:
- Internal Standard Addition: Adds a known, fixed amount of gas standard to each 3.5″ sorbent tube using a high-precision regulator and fixed volume loop.
- Dry Purging: Removes moisture from the sorbent tubes using an electronically controlled mass flow of drying gas.Â
These features are especially useful for ambient, indoor, and workplace air monitoring, where moisture and inconsistent standard addition can compromise data quality.
Applications of the ISDP
Whether you’re tracking down VOCs, identifying malodors, or ensuring workplace safety, the ISDP adds robustness and efficiency to your method. Applications include:
- Toxic air pollutant monitoring (US EPA TO-17)
- Volatile Organic Compound (VOC) analysis
- Indoor and workplace air studies (ISO 16000-6, ISO 12219, ISO 16017)
- Quality control in regulated air sampling methods
For analysts working in compliance-heavy industries, the ISDP streamlines method validation and supports defensible data, two must-haves to meet regulatory standards.
Key Advantages of the GERSTEL ISDP
The ISDP is designed to simplify and strengthen your air analysis workflows. Whether you’re building methods for compliance or troubleshooting inconsistent results, the ISDP provides a reliable, automated solution that boosts performance across the board:
Accuracy: Precise and reproducible internal standard addition
Reproducibility: Elimination of dated needle valve and manual pressure regulators for better instrument-to-instrument reproducibility
Cost Savings: Lowered total cost of ownership by reducing manual troubleshooting and by maintaining week-to-week stable workflows
Moisture Control: Removal of water through dry purge improves analyte recovery and GC performance
Regulatory Compliance: Meets standards for regulatory methods like US EPA TO-17
Automation: Reduces manual intervention and analyst workload
QA/QC Efficiency: Simplified QA/QC review and easier method validation
Seamless Integration: Operates through GERSTEL MAESTRO for seamless integration to GC-MS control software
By automating two critical sample prep steps, internal standard addition and dry purging, the ISDP helps your lab generate more consistent, defensible results while saving time.
Case Study: Methylene Chloride Monitoring in Indoor Air
A recent GERSTEL application note (AppNote 282) demonstrated the ISDP’s effectiveness in monitoring methylene chloride (CH₂Cl₂), a solvent facing increasing scrutiny due to its health risks. With most consumer and commercial uses banned by the EPA as of April 2024, industries still relying on methylene chloride must implement stringent baseline air monitoring and chemical protection plans.
Method Overview
The study utilized the GERSTEL TD Core system paired with the ISDP and an Agilent GC-MS. Air samples were drawn through Carbopack B/X sorbent tubes and analyzed using thermal desorption GC-MS, with internal standards added automatically by the ISDP.
The ISDP enabled automated internal standard spiking using a four-compound gas standard, delivering high precision and reproducibility across multiple replicates (RSDs as low as 2.29%).
Additionally, the ISDP’s dry purge function removed excess water from humid samples, improving analyte transfer to the GC column and reducing variability.
Real-World Results
Indoor air samples were collected from various locations around GERSTEL’s facility, including labs, offices, and a warehouse. All measured methylene chloride concentrations were well below the OSHA PEL (25 ppmV), with the highest values found in laboratory areas.
These results show not only the utility of the ISDP in capturing accurate, reproducible data but also its value in establishing baseline air quality for regulated compounds.
Ready to Upgrade Your Air Analysis Workflow?
Adding an ISDP to your thermal desorption system not only future-proofs your workflow but also positions your lab to meet rising regulatory demands with ease. Whether you’re monitoring workplace exposure, investigating environmental pollutants, or analyzing ambient air for VOCs, the ISDP brings reliability and automation to every step.
Learn More about the GERSTEL ISDP:
