Melamine detection sprang into the forefront of U.S. consciousness in 2007 and 2008 with the pet food and infant and milk products to increase apparent protein content by increasing the nitrogen content of the material. Incomplete cattle feed. Kidney failure in pets from the formation of crystals due to melamine was the cause of pet deaths. The infant formula and powdered milk scares evolved from the use of milk-based of renal complications in children in China, and the discovery of milk-derived ingredients from Chinese sources in U.S. products that included milk (liquid and powdered), yogurt, candy, coffee drinks, and more. The FDA established a 2.5ppm acceptable level for adult foods and a 1ppm level for infant formula.

As a result of these events, the government and food industries considered analytical tools for detecting melamine, cyanuric acid, melamine cyanurate, ammelide, and ammeline that would be faster than the liquid chromatography methods that were in use. In addition to speed, other desirable analytical capabilities would include:

• Sensitivity
• Specificity
• Fast detection
• Low-cost
• Minimal or zero sample preparation
• Non-destructive analysis
• Ability to measure melamine in a range of complex food matrices
• Portability for on-site/manufacturing plant analysis

The SR-Series of NIR spectrometers are well-suited for melamine screening across a range of materials, including liquids and powdered dairy products. These NIR spectrometers use a stable thermo-electrically cooled InGaAs array directly mated to a fiber optic for maximum throughput. The TE-cooled multiplexed InGaAs array includes all necessary order separating and/or long pass filters. Gratings are optimized for the highest signal-to- noise ratio across the full range. The spectrometers come with an SMA-905 fiber optic input. Units can be customized with a wide range of fiber optic accessories, including probes, lenses, integrating spheres, and right angle diffuser. Customized input formats are also available.

All SPECTRAL EVOLUTION spectrometers come with DARWin SP Data Acquisition software. DARWin SP allows for rapid analysis and easy set-up. Spectra are stored as ASCII for use with 3rd party analysis software, including chemometrics. There’s no pre- processing necessary before you use the spectra with an analysis program.

An example configuration for detecting melamine included the following:

• SR-2500 with a spectral range of 350-2500nm
• 20 Watt tungsten-halogen light source with user-adjustable output
• Li-ion rechargeable battery
• Probe for reflectance with an SMA-905 fiber connection
• Probe for transflectance with SMA-905 fiber
• One meter fiberoptic
• DARWin SP Data Acquisition software
• One-touch autoexposure control

SR-Series

The  SR-Series of NIR spectrometers provide affordable, accurate, and easy to use systems for melamine screening in milk (liquid and powdered) yogurt, candy, coffee drinks, and more.

Accessories can include a contact probe with 5 watt tungsten halogen illuminator and pistol grip, additional fiber optic illumination modules, a cuvette and filter holder, bifurcated dark field reflectance probe, stainless steel irradiance probe, and a stainless steel reflectance probe.