Trace chemical analysis by Surface-Enhanced Raman Spectroscopy (SERS) is made quick and easy with sample vials coated with a patented SERS-active sol-gel. A solution containing the chemical of interest is simply injected into the vial, which is placed in a Raman spectrometer sample compartment, the spectrum is recorded, and science moves forward.
The measured SER spectrum consists of a wavelength distribution of bands corresponding to molecular vibrations specific to the chemical being analyzed. This allows identification of numerous chemicals, biochemicals and pharmaceuticals. In most cases a simple calibration allows quantifying the chemicals by the intensity of the Raman spectral bands.
SERS mechanism and 2 mL Simple SERS vial photo
Advantages:
- Small sample volumes (microliters)
- No sample preparation
- No drying required
- Suitable for multiple solvents
- Suitable for acids or bases
- Suitable for VIS to NIR excitation (532 to 1064 nm)
Benefits:
- Signal enhancements of 106 or greater
- Detection limits: ppb, nM, mg/L
- Fast response time (< 1sec)
- Reproducible (vial-to-vial)
- Long shelf life (> 1 year)
More than 500 chemicals and biochemicals have been measured, such as inorganics (Na4Fe II(CN)6), physiological chemicals (uric acid), and pesticides (fonofos). Various solvents can be used, such as methanol, and water. And the vials can be used with any commercial Raman instruments, regardless of excitation wavelength. The vials are manufactured and sold in batches of 10 – 100 using very specific conditions. These manufacturing conditions reproduce film thickness and SERS enhancement allowing repeatable and quantitative measurements. The measured standard deviation for 10-3 M p-aminobenzoic acid (PABA) from vial-to-vial in different batches is less than 10%.
