Environmental contaminant testing traditionally requires samples to be sent to a lab. Portable SPR changes that — bringing real-time detection to the field.
Introduction
Traditional methods for testing environmental contaminants are commonly done in centralized lab facilities, which require the collection, transportation, storage, and preparation of samples. These steps require time, and will certainly delay any proactive actions necessary to safeguard the environment and health of those who are directly impacted by the presence of environmental contaminants — for instance, residents whose main water source comes from water wells at risk of contamination.
Having access to a mobile test platform is even more important if the testing site is not easily accessible with regular transport from any centralized lab facility. This blog highlights the deployment of P4SPR™ to monitor RDX (1,3,5-trinitroperhydro-1,3,5-triazine) in groundwater near downgradient wells. This research was conducted by Prof. Jean-François Masson's research group at Université de Montréal.
Background
RDX is an energetic material left on the ground following military exercises. It is not well retained in soil so it is often transported to ground and surface water by rainfall or snow melt. To ensure that the ground water is safe to use by the local population, the water must be tested, which is often done by HPLC-UV analysis — a method approved by the Environmental Protection Agency (EPA) known as EPA method 8330b. This method relies on a large laboratory instrument which is normally located in a centralized lab facility. Thus, the samples must be carefully transported and stored before being prepared for analysis.
Normally, small molecules such as RDX would be difficult to detect with an SPR instrument due to its small size. However, an SPR setup based on a molecularly-imprinted polymer (MIP), bisaniline, with crosslinked gold nanoparticles was found to bind to RDX with high affinity. Moreover, the use of MIP is ideal for field-deployed instruments as it is simple and less susceptible to environmental degradation.
Highlights of Using P4SPR™ in the Field
The P4SPR™ was deployed at a military training site to sample ground water for the detection of RDX using a MIP-coated sensor chip. Summer and winter conditions were tested on the instrument with success, with the setups being simple and experiments being fast to complete. The results obtained onsite and in the lab correlated well to samples analyzed by the HPLC EPA method 8330b. The authors also demonstrated the potential of the P4SPR to be used for onsite continuous monitoring.
Conclusions
The use of a portable SPR instrument has the advantage of faster result turnaround time than the standard EPA method due to the lack of need to transport and store the samples, as well as eliminating some sample preparation steps. The P4SPR's portability and real-time detection capability make it a powerful tool for environmental contaminant monitoring in remote or field settings.
Reference
[1] Thibault Brulé, Geneviève Granger, Natalia Bukar, et al. A field-deployed surface plasmon resonance (SPR) sensor for RDX quantification in environmental waters. Analyst, 2017, 142, 2161–2168.