Utilizing NIR Technology for BioSafety Labs and Whole Room Sterilization

Sterile fill isolator areas and rooms used for biological experiments (BioSafety Level 3 and 4 rated labs) require periodic decontamination and virus deactivation. The National Cancer Institute (NCI) Research and Production Center at Ft. Detrick, Maryland uses vaporized hydrogen peroxide to decontaminate whole areas and rooms. The NCI is part of the National Institue of Health (NIH).

Whole room VHP sterilization
Whole room sterilization occurs due to a vaporized hydrogen peroxide generator being connected to the HVAC system. Numbers mark locations of biological indicators used in the study. In the illustration, one of the points where biological indicators are used may be good candidates for a real-time sterilant vapor monitoring image credit

As shown in the photos below, a series of G-SST probes have been installed in BioSafety labs and sterile fill isolators at the NIH Center. By connecting these probes with Guided Wave’s Hydrogen Peroxide Vapor Analyzer (HPVA), Sterilization Technicians can verify that sterilant was properly dispersed at kill level concentrations in the room. A G-SST probe is often wall-mounted at location(s) of the room that is more challenging to reach by sterilant vapors. The biological indicators can help to identify a region of the room where a permanently mount real-time monitor of sterilant concentration is of value.

Inspection of G-SST Vapor Probe for whole room BSL3 lab
Long time Sales Representative and Partner, Greg Gargus of Prochem Scientific, inspecting the installation of a G-SST probe during commissioning at NIH building in Maryland, USA.

The HPVA is a complete NIR analytical system comprised of three main components: 1) the NIR photometer, 2) a pair of fiber optic cables for each probe, and 3) the sample interface, in this case the G-SST probe. The photometer both transmits the source light and quantifies the light that was not absorbed by the sample. Thermally stable process grade fiber optic cables are used to carry the light from the photometer to the sample and back. Using high performance fiber cables permits the sample interface to be located up to 100 meters from the photometer. Hence, NIR technology is now an option for biosafety environments.

If multiple rooms are decontaminated in a sequence, then it is possible to set up multiple probes (or one probe in each room) and then serially monitor each location/fiber pair. Simpling connecting the fiber optic cable pairs in order to the Hydrogen Peroxide Vapor Analyzer allows the decontamination cycle to be monitored with a single analyzer. This provides a cost-saving compared to having a dedicated analyzer for each room or monitoring location.   For temporary use in a hospital or other office type buildings, the G-SST vapor probes can be mounted on vertical stands or other movable fixtures.

Getting the Sterilant into the Room

The G-SST probe can also be installed in the HVAC system. By placing the probe immediately inline after the hydrogen peroxide generator enables Sterilization Technicians to monitor the concentration of Vaporized Hydrogen Peroxide or Ethylene Oxide gas being released into the room. By monitoring the production of sterilant in addition to the concentration achieved in each room, Technicians can verify proper operation of the complete sterilization system.  

G-SST Probe installed in the HVAC system. Fiber Optic Cables connected to the probe are run to the HPV analyzer
G-SST Probe installed in the HVAC system. Fiber Optic Cables connected to the probe are run to the HPV analyzer

The need to monitor Vaporized Hydrogen Peroxide in the HVAC duct system is supported by a 2008 study by Department of Immunology, Max‐Planck Institute for Infection Biology, Germany, “VHP treatment [supplied by an HVAC system] is an effective means of reducing and eliminating room contaminations of M. tuberculosis”.

Why Monitor Sterilant Concentrations with NIR Spectroscopy?

Near-infrared spectroscopy provides a sterilization monitoring solution that operates in both a positive and negative atmosphere. Electrochemical sensors cannot operate in a vacuum and can also be damaged or poisoned by high sterilant concentrations. Because NIR spectroscopy uses light to monitor the chemical concentrations, the Vaporized Hydrogen Peroxide Analyzer can monitor sterilant levels under non-condesening conditions.

The Hydrogen Peroxide Vapor Analyzer is a Hassle-Free Sterilant Monitor

The HPV analyzer is calibrated at the factory. No programming is required by the user. Start-up requires powering the HPV analyzer, connecting the probe or probes via the fiber optic cables, taking a ZERO reading in the dehumidified isolator and the H2O2 and H2O concentration measurements may begin.

Need Help Monitoring Biosafety Room Sterilization?

Guided Wave has been measuring H2O2 and H2O concentrations in various vapor mixtures for over 20 years using near-infrared (NIR), fiber optic-coupled analyzers. Contact us to discuss your specific installation requirements and we can provide a fit to purpose solution. We also offer HPVA rental equipment to the US and European markets.