Grantee Research Project Results
Final Report: SERS for Rapid, On-site Multicomponent Analysis of Water Quality
EPA Contract Number: 68HERC23C0013Title: SERS for Rapid, On-site Multicomponent Analysis of Water Quality
Investigators: Spencer, Kevin M.
Small Business: EIC Laboratories Inc.
EPA Contact: Richards, April
Phase: I
Project Period: December 1, 2022 through May 31, 2023
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) Phase I (2023) RFA Text | Recipients Lists
Research Category: SBIR - Water , SBIR - Sustainability , SBIR - Homeland Security , SBIR - Air and Climate
Description:
The program goal is to develop a field portable water quality monitor to be used by non-specialists based on Surface-Enhanced Raman Spectroscopy (SERS). SERS adsorbs chemicals of interest on nanoroughened coinage metals and collects scattered Raman signals using a laser. The electromagnetic wave interactions between the irradiation source and the surface plasmon enhance the Raman signal of the contaminants by several orders of magnitude enabling identification of contaminants into the parts per billion level or lower. The developed portable system will simultaneously measure ppb concentrations levels or lower for a wide variety of contaminants, including pesticides, pharmaceuticals, stimulants, toxins and heavy metals, In this program, EIC will fabricate a set of unique SERS sensors that contain a magnetic core. SERS- active metals coated over a magnetic core have shown promise on previous studies at ppt-ppb level detection and create a simple, effective method for sample preconcentration.
Summary/Accomplishments (Outputs/Outcomes):
In the Phase I program, EIC created a series of SERS sensors that used gold, silver or silver over gold coating protocols to optimize adsorption of a wide variety of contaminants. During the Phase I program, each sensor was optimized on a basis set of 13 commonly encountered water contaminants. The contaminants analyzed included perfluorooctanoic acid, nicotine, caffeine, cotinine, acephate, chlorpyrifos, glyphosate, coumaphos, pendimethalin, penicillin G, carbamazepine, acetaminophen and ibuprofen These contaminants were analyzed and optimized against the sensor set. In addition, preliminary evaluations on a variety of other contaminants was performed. The results demonstrated that ppb or lower concentrations could be attained for the water contaminants using a magnetic collection device. Further, we demonstrated that lower detection limits can be attained by increasing the water volume from 1 mL to 250-500 mL, without an increase in analysis time. The Phase II program will increase the number of analytes in the library, increase the number of SERS-sensor types, optimize a software routine for fully automated acquisition and analysis, obtain and validate the system against wastewater samples and fabricate and field test a prototype.
Conclusions:
The Phase I program demonstrated successful detection of several classes of emerging contaminants of concern to the EPA using different types of gold- and silver-coated magnetic nanoparticles. Each of these compounds provided spectra that allowed unique identification, even for similar molecules like nicotine and cotinine. This will not always be the case; preliminary data indicates that many of the PFAS chemicals will have a similar spectrum. This is not an impediment however as the EPA requirements are for the total PFAS present in water and not for individual PFAS compounds. Detection limits were determined for each of the compounds evaluated and either met the desired limits or a realistic pathway to achieve the desired detection limit within the next phase of research was presented. The Phase I results were highly encouraging and enable a straightforward transition to a Phase II program. The future research will extend the number of contaminants by adding other groups of contaminants (for example, heavy metals, PCBs, PBBs) as well as increasing the number of individual components investigated during this program. Creation of different SERS sensor shapes with a magnetic core will be prepared and optimized. The sampling volume and SERS sensor concentrations will be finalized and a precise protocol defined. A fieldable prototype with spectral library and searching software to identify and statistical algorithms to quantify multiple components simultaneously will be prepared and field tested.
The goal of the research is to create a portable system that can simultaneously measure multiple components in a water supply. The easier a chemical analysis can be at a reasonable price, more frequent measurements can be performed increasing water security, which is the ultimate goal. The compact SERS can be used by municipalities as a cost-effective alternative (<$40 per measurement) to the current high-end water analyzers that are expensive, have long turn-around times if sent to an external laboratory and require sample preparation. In addition, it can serve as a field water analyzer during disasters, such as fires or hurricanes, where significant levels of chemical contaminants can enter the water supply and be rapidly redistributed. The water security market is significant and this unique analyzer will allow EIC to penetrate the market and serve a niche that is currently unfulfilled. EIC will create the portable water analyzer and the array of SERS magnetic nanoparticles for commercial and governmental agencies and sell them through its commercial affiliate InPhotonics.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.