Continuous Temperature-Dependent Raman Spectroscopy of Melamine and Structural Analog Detection in Milk Powder

Schmidt, Walter F.; Broadhurst, C. Leigh; Qin, Jianwei; Lee, Hoyoung; Nguyen, Julie; Chao, Kuanglin; Hapeman, Cathleen J.; Shelton, Daniel R.; Kim, Moon S.

doi:10.1366/14-07600

Cited by 16 publications

(6 citation statements)

References 38 publications

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“…Urea, chemical formula CO(NH 2 ) 2 , has two –NH 2 groups joined by a carbonyl (C=O) functional group, as shown in Figure 2a. The high intensity peak of urea at 1009 cm −1 due to (C–N–C) stretching is most definitive to its identification and quantification [30,31], while its other peaks (not labeled in Figure 3: 1646 cm −1 from asymmetrical bending, 1541 cm −1 from NH symmetrical bending, and 1175 cm −1 from H–N–H bending) are much less prominent. Ibuprofen (Figure 2b) has carboxylic acid and an aromatic ring as functional groups; acetaminophen (Figure 2c) also has an aromatic ring.…”

Section: Resultsmentioning

confidence: 99%

A Spatially Offset Raman Spectroscopy Method for Non-Destructive Detection of Gelatin-Encapsulated Powders

Chao

Dhakal

Qin

et al. 2017

Sensors

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Non-destructive subsurface detection of encapsulated, coated, or seal-packaged foods and pharmaceuticals can help prevent distribution and consumption of counterfeit or hazardous products. This study used a Spatially Offset Raman Spectroscopy (SORS) method to detect and identify urea, ibuprofen, and acetaminophen powders contained within one or more (up to eight) layers of gelatin capsules to demonstrate subsurface chemical detection and identification. A 785-nm point-scan Raman spectroscopy system was used to acquire spatially offset Raman spectra for an offset range of 0 to 10 mm from the surfaces of 24 encapsulated samples, using a step size of 0.1 mm to obtain 101 spectral measurements per sample. As the offset distance was increased, the spectral contribution from the subsurface powder gradually outweighed that of the surface capsule layers, allowing for detection of the encapsulated powders. Containing mixed contributions from the powder and capsule, the SORS spectra for each sample were resolved into pure component spectra using self-modeling mixture analysis (SMA) and the corresponding components were identified using spectral information divergence values. As demonstrated here for detecting chemicals contained inside thick capsule layers, this SORS measurement technique coupled with SMA has the potential to be a reliable non-destructive method for subsurface inspection and authentication of foods, health supplements, and pharmaceutical products that are prepared or packaged with semi-transparent materials.

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Section: Resultsmentioning

confidence: 99%

A Spatially Offset Raman Spectroscopy Method for Non-Destructive Detection of Gelatin-Encapsulated Powders

Chao

Dhakal

Qin

et al. 2017

Sensors

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“…A practical application developed in our laboratory is a hyperspectral Raman imaging system with mixture analysis algorithms that can simultaneously identify and map four adulterant particles mixed into dry milk at concentration levels from 0.1-5.0 % [5]. Extending this analysis to include the additional vector of temperature improves detectability [22]. Previous Raman analyses of mixed lipids, also coupled with analysis algorithms, have shown promise for rapid, nondestructive detection of FA species in carcasses and renderings, for example [25,32,33].…”

Section: Discussionmentioning

confidence: 99%

“…Continuous gradient temperature Raman spectroscopy (GTRS) applies the precise temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a rapid, straightforward technique to identify molecular rearrangements that occur near or at phase transitions. We have successfully utilized the technique with amines, peptides, complex food substances, and lipids [5,[21][22][23][24]. Lipids in particular pose a spectroscopic challenge due to the repetitive nature of the acyl/ olefin chains and drastic decreases in melting points as the number of double bonds increases [13,[18][19][20][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Continuous Gradient Temperature Raman Spectroscopy of Oleic and Linoleic Acids from −100 to 50 °C

Broadhurst

Schmidt

Kim

et al. 2016

Lipids

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We analyzed the unsaturated fatty acids oleic (OA, 18:1n-9) and linoleic (LA, 18:2n-3), and a 3:1 LA:OA mixture from -100 to 50 °C with continuous gradient temperature Raman spectroscopy (GTRS). The 20 Mb three-dimensional data arrays with 0.2 °C increments and first/second derivatives allowed rapid, complete assignment of solid, liquid, and transition state vibrational modes. For OA, large spectral and line width changes occurred in the solid state γ to α transition near -4 °C, and the melt (13 °C) over a range of only 1 °C. For LA, major intensity reductions from 200 to 1750 cm and some peak shifts marked one solid state phase transition at -50 °C. A second solid state transition (-33 °C) had minor spectral changes. Large spectral and line width changes occurred at the melt transition (-7 °C) over a narrow temperature range. For both molecules, melting initiates at the diene structure, then progresses towards the ends. In the 3:1 LA:OA mixture, some less intense and lower frequencies present in the individual lipids are weaker or absent. For example, modes assignable to C8 rocking, C9H-C10H wagging, C10H-C11H wagging, and CH3 rocking are present in OA but absent in LA:OA. Our data quantify the concept of lipid premelting and identify the flexible structures within OA and LA, which have characteristic vibrational modes beginning at cryogenic temperatures.

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“…Addition of Non-Declared Substances: Urea, melamine, dicyandiamide, sodium bicarbonate, ammonium sulfate, and sucrose are the most frequently used adulteration agents for milk and dairy products [251,252]. Infrared spectroscopy, FT-MIR, and MIRS have been widely applied to determine raw milk and milk powder adulteration by using waste whey [253,254].…”

Section: Milk and Dairy Productsmentioning

confidence: 99%

Fraud in Animal Origin Food Products: Advances in Emerging Spectroscopic Detection Methods over the Past Five Years

Hassoun

Måge

Schmidt

et al. 2020

Foods

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Animal origin food products, including fish and seafood, meat and poultry, milk and dairy foods, and other related products play significant roles in human nutrition. However, fraud in this food sector frequently occurs, leading to negative economic impacts on consumers and potential risks to public health and the environment. Therefore, the development of analytical techniques that can rapidly detect fraud and verify the authenticity of such products is of paramount importance. Traditionally, a wide variety of targeted approaches, such as chemical, chromatographic, molecular, and protein-based techniques, among others, have been frequently used to identify animal species, production methods, provenance, and processing of food products. Although these conventional methods are accurate and reliable, they are destructive, time-consuming, and can only be employed at the laboratory scale. On the contrary, alternative methods based mainly on spectroscopy have emerged in recent years as invaluable tools to overcome most of the limitations associated with traditional measurements. The number of scientific studies reporting on various authenticity issues investigated by vibrational spectroscopy, nuclear magnetic resonance, and fluorescence spectroscopy has increased substantially over the past few years, indicating the tremendous potential of these techniques in the fight against food fraud. It is the aim of the present manuscript to review the state-of-the-art research advances since 2015 regarding the use of analytical methods applied to detect fraud in food products of animal origin, with particular attention paid to spectroscopic measurements coupled with chemometric analysis. The opportunities and challenges surrounding the use of spectroscopic techniques and possible future directions will also be discussed.

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Continuous Temperature-Dependent Raman Spectroscopy of Melamine and Structural Analog Detection in Milk Powder

Cited by 16 publications

References 38 publications

A Spatially Offset Raman Spectroscopy Method for Non-Destructive Detection of Gelatin-Encapsulated Powders

A Spatially Offset Raman Spectroscopy Method for Non-Destructive Detection of Gelatin-Encapsulated Powders

Continuous Gradient Temperature Raman Spectroscopy of Oleic and Linoleic Acids from −100 to 50 °C

Fraud in Animal Origin Food Products: Advances in Emerging Spectroscopic Detection Methods over the Past Five Years

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