Infrared Spectroscopy

Gillie, J. Kevin; Hochlowski, Jill E.; Arbuckle-Keil, Georgia

doi:10.1021/a1000006w

Cited by 45 publications

(26 citation statements)

References 114 publications

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“…4 Mass spectrometry methods 5, 6 have advanced through improved mass analyzers 7 and sample introduction techniques. 8 Spectroscopy can provide analyte-specific information from absorbance 9 or Raman 10 techniques. In addition, clinical diagnostic tools 11 such as enzyme-linked immunosorbent assay (ELISA) 12 are broadly used for targeted detection of biomolecules of interest.…”

Section: Introductionmentioning

confidence: 99%

“Flow Valve” Microfluidic Devices for Simple, Detectorless, and Label-Free Analyte Quantitation

et al. 2012

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Simplified analysis systems that offer the performance of benchtop instruments but the convenience of portability are highly desirable. We have developed novel, miniature devices that feature visual inspection readout of a target’s concentration from a ~1 μL volume of solution introduced into a microfluidic channel. Microchannels are constructed within an elastomeric material, and channel surfaces are coated with receptors to the target. When a solution is flowed into the channel, the target crosslinks multiple receptors on the surface, resulting in constriction of the first few millimeters of the channel and stopping of flow. Quantitation is performed by measuring the distance traveled by the target solution in the channel before flow stops. A key advantage of our approach is that quantitation is accomplished by simple visual inspection of the channel, without the need for complex detection instrumentation. We have tested these devices using the model system of biotin as a receptor and streptavidin as the target. We have also characterized three factors that influence flow distance: solution viscosity, device thickness, and channel height. We found that solution capillary flow distance scales with the negative logarithm of target concentration and have detected streptavidin concentrations as low as 1 ng/mL. Finally, we have identified and evaluated a plausible mechanism wherein time-dependent channel constriction in the first few millimeters leads to concentration-dependent flow distances. Their simplicity coupled with performance makes these “flow valve” systems especially attractive for a host of analysis applications.

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Section: Introductionmentioning

confidence: 99%

“Flow Valve” Microfluidic Devices for Simple, Detectorless, and Label-Free Analyte Quantitation

et al. 2012

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“…11,12 Information about molecular structure of complex mixtures can be obtained from Fourier transform infrared (FTIR) spectroscopic analysis. 13,14 The ease of sample preparation and operation, and nondestructive nature of analyses make FTIR attractive as a characterization technique to analyze gel formulations.…”

Section: Introductionmentioning

confidence: 99%

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Islam

Rodrı́guez-Hornedo

Ciotti

et al. 2004

AAPS J

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The objective of the present study is to evaluate the polymersurfactant and polymer-neutralizer interactions in topical aqueous, anhydrous, and hydroalcoholic gel formulations using Fourier transform infrared (FTIR) spectroscopy. The gels were prepared by dispersing Carbomer (Carbopol 980) in water and ethanol for aqueous and anhydrous systems, respectively. Glycerol and propylene glycol were also added to ensure that the compositions of gels closely resembled those used in typical topical gel formulations. Comparisons of the spectra of Carbopol dispersions in aqueous, anhydrous, and hydroalcoholic systems, performed for the first time, show Carbopol-neutralizer and Carbopol-surfactant interactions vary depending on the nature of the solvents used for gel formation. Analysis of the spectra of aqueous gel formulations indicates significant presence of ionized carboxyl groups only at higher pH (~8.0). Drying of the aqueous gels causes a shift in the carbonyl stretch band toward higher energy, suggesting changes in polymer-neutralizer interaction. Anhydrous gels exhibit 2 different carbonyl stretch bands: the one at ~1653 cm -1 is related to the carboxyl group that is hydrogen bonded and is akin to hydrous gels; the second one at ~1717 cm -1 is indicative of free carbonyl groups. The carbonyl bands of dried gels appear at different energy levels than the solvated gels. This shift resulting from solvent evaporation, reported for the first time, indicates changes in hydrogen bond characteristics. The results show that FTIR can be a good technique compared with other more time-consuming means of analysis for topical formulations.

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“…Such statistical methods include partial least-squares (PLS) regression (36), while a popular and powerful series of machine learning strategies (37) are based on methods of evolutionary computing (4), such as genetic algorithms (GAs) (4,19,24) and genetic programming (GP) (6,33). Fourier transform infrared (FT-IR) spectroscopy involves the observation of vibrations of molecules that are excited by an infrared beam, and an infrared absorbance spectrum represents a "fingerprint" which is characteristic of any chemical or biochemical substance (18,43). This technique is also very rapid (taking seconds) and has been shown to be a valuable tool for the characterization of axenically cultured bacteria (22,34,38,47), including single-gene knockout strains (41).…”

mentioning

confidence: 99%

Rapid and Quantitative Detection of the Microbial Spoilage of Meat by Fourier Transform Infrared Spectroscopy and Machine Learning

Ellis

Broadhurst

Kell

et al. 2002

Appl Environ Microbiol

285

197

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Fourier transform infrared (FT-IR) spectroscopy is a rapid, noninvasive technique with considerable potential for application in the food and related industries. We show here that this technique can be used directly on the surface of food to produce biochemically interpretable "fingerprints." Spoilage in meat is the result of decomposition and the formation of metabolites caused by the growth and enzymatic activity of microorganisms. FT-IR was exploited to measure biochemical changes within the meat substrate, enhancing and accelerating the detection of microbial spoilage. Chicken breasts were purchased from a national retailer, comminuted for 10 s, and left to spoil at room temperature for 24 h. Every hour, FT-IR measurements were taken directly from the meat surface using attenuated total reflectance, and the total viable counts were obtained by classical plating methods. Quantitative interpretation of FT-IR spectra was possible using partial leastsquares regression and allowed accurate estimates of bacterial loads to be calculated directly from the meat surface in 60 s. Genetic programming was used to derive rules showing that at levels of 10 7 bacteria·g ؊1 the main biochemical indicator of spoilage was the onset of proteolysis. Thus, using FT-IR we were able to acquire a metabolic snapshot and quantify, noninvasively, the microbial loads of food samples accurately and rapidly in 60 s, directly from the sample surface. We believe this approach will aid in the Hazard Analysis Critical Control Point process for the assessment of the microbiological safety of food at the production, processing, manufacturing, packaging, and storage levels.The last decade has seen an exponential increase in the consumer demand for poultry and poultry products, fueled in part by dietary health considerations. Fears over microbiological food safety issues, especially the incidence of Salmonella spp. (23,49) and Campylobacter spp. (11,39), in conjunction with consumer demand for a product of consistently high quality, have focused attention on a particular area of the food production industry, namely, the requirement for a rapid (less than a few minutes) and accurate detection system for microbiologically spoiled or contaminated meat (3).At present, no such technology exists in the food industry within the Hazard Analysis Critical Control Point system for the microbiological safety and quality of meat and poultry products (20,26,48).Muscle foods, such as meat and poultry, are described as spoiled if organoleptic changes make them unacceptable to the consumer. These organoleptic characteristics may include changes in appearance (discoloration), the development of off odors, slime formation, changes in taste, or any other characteristic which makes the food undesirable for consumption (25,26). While endogenous enzymatic activity within muscle tissue postmortem can contribute to changes during storage (1,25,32,44), it is generally accepted that detectable organoleptic spoilage is a result of decomposition and the formation of metaboli...

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Infrared Spectroscopy

Cited by 45 publications

References 114 publications

“Flow Valve” Microfluidic Devices for Simple, Detectorless, and Label-Free Analyte Quantitation

“Flow Valve” Microfluidic Devices for Simple, Detectorless, and Label-Free Analyte Quantitation

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Rapid and Quantitative Detection of the Microbial Spoilage of Meat by Fourier Transform Infrared Spectroscopy and Machine Learning

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