Rapid screening test for adulteration in raw materials of dietary supplements

Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) sampling was evaluated for use in screening for adulteration in raw materials used in the formulation and manufacture of dietary supplements. ATR requires minimal-to-no sample preparation and the method runs in less than ten minutes, providing a robust, rapid screening test for a variety of possible adulterants in the raw materials of dietary supplements. Spectral comparison methods targeting structural similarities of known adulterants were developed. In this study, FTIR-ATR was used to detect the presence of known adulterants intentionally spiked into dietary ingredients, including erectile dysfunction drugs, steroids, weight loss drugs and Melamine.     

Investigation of Hydrolysis in Poly（ethylene terephthalate） by FTIR-ATR

The hydrothermal aging of poly(ethylene terephthalate)(PET) was investigated at 70 95 °C. A new method to investigate the hydrolysis degree of PET by Fourier transform infrared spectroscopy(FTIR) was proposed. The spectra during the hydrothermal aging were measured using attenuated total reflection accessory(ATR). Peak resolving of carbonyl regions was performed, and the ratio of two groups of bands representing carboxylic acids and esters respectively were calculated to show the hydrolysis degree of ester groups in PET. The acid/ester ratio shows exactly the same trend as the average chain scission number per unit mass at various temperatures and thus can be used as a parameter to characterize the hydrolysis and random chain scission of PET. This method related to the hydrolysis mechanism directly, is simple, fast and convenient compared to the traditional methods such as viscometry, end-group titration and size exclusion chromatography(SEC). It may also be useful in hydrolysis characterization of other polyesters.     

FTIR-ATR与显微成像法结合观察NaNO3气溶胶结晶过程

阶梯状改变环境湿度, 利用FTIR-ATR(Attenuated Total Reflection)技术以及显微成像技术观察NaNO3气溶胶微粒的结晶动力学。多次实验证实NaNO3液滴在饱和点74.5%RH之后开始陆续风化, 至风化点53%RH之后结晶速率明显增快, 但并不是相对湿度越低, 结晶速率越快, 而是相对湿度的变化率越大, 结晶速率越快。对数据进行非线性拟合发现在湿度下降处结晶速率呈指数关系, 在湿度稳定時结晶速率呈线性关系。并且通过显微镜观察到尽管样品NaNO3液滴的直径在同一个数量级上, 仍能看出结晶速率与液滴半径关系紧密, 半径越大越易结晶, 结晶的相对湿度越高。     

Monitoring of oil-based polyurethane synthesis by FTIR-ATR

Oil-based polyurethanes were synthesized from triglyceride oil-based hydroxyl containing material and toluene diisocyanate or hexamethylene diisocyanate for wound dressing applications. The reactions were carried out with or without catalyst at 90 °C. The amount of free isocyanate during the reaction was determined by a FTIR-ATR method, and the results were compared with those from a back-titration method. The data obtained were used for determination of kinetic parameters.     

Spectral Investigation of Phosphorus Compounds in Spinacia Oleracea Using Fourier Transform Infrared Method

The study uses the Fourier transform infrared spectroscopy method to evaluate the influence of phosphogypsum from the soil on the growth and accumulation of nutrients in Spinacia oleracea. Attenuated total reflectance spectra of Spinacia oleracea roots and stems originated from plants cultivated on 28% to 52% phosphogypsum enriched soil have been studied in the 4000–600 cm^?1 area. The structure of the infrared absorption bands for spinach roots and stems and for the soil where plants were grown was analyzed. Thus, it was observed that phosphorus–oxygen bonds contribution can be identified both in roots and stems absorption spectra. The significance of the research is the possibility to use the infrared investigation as rapid technique, particularly useful for agriculture, to study the extraction and assimilation process of the compounds containing phosphorus and nitrogen from the soil in which the spinach seedlings grew. In the case of this study, it was observed that the absorption of phosphorus in the spinach roots and stems has not the same effect. The analysis of obtained data indicated that the assimilation of phosphorus from phosphogypsum enriched soil induces changes in spinach roots structure that are most likely due to an increase synthesis of proteins, rather than to a decrease in carbohydrates quantity.     

Modification of polysulfone membranes 5. Effect of n-butylamine and allylamine plasma

This paper describes some properties of microwave plasma polymers of n-butylamine and allylamine deposited on the surface of polysulfone substrate. Contact angle evaluation, ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy analysis and estimation of pore size distribution of ultrafiltration polysulfone membranes were used. It was found that addition of Ar to the amine vapor significantly stabilized the plasma and converted it to the ablation mode. The surface became more hydrophilic and the surface groups were enriched in oxygen. Both amines gave deposits of various compositions: the n-butylamine polymer was not as enriched in amines as the polymer formed from allylamine. However, the amounts of nitrogen in both deposits indicated allylamine to be the precursor for the preparation of membranes with weakly basic functionalities. When porous membranes are modified, the ultrafilters obtained may be named `fouling protected' as they do not foul so intensively with proteins as their unmodified analogues. To a lesser extent, similar behavior was shown by membranes modified by deposition of plasma-polymerized n-butylamine.     

ATR-FTIR study of Bacillus sp. and Escherichia coli settlements on the bare and Al2O3 coated ZnSe internal reflection element

FTIR-ATR has been used for understanding the interaction between bacteria and surfaces in the adsorption progress.     

FTIR-ATR技术研究聚氨酯类文物保护材料的光降解

Polyurethanes are one kind of relic protection materials commonly used. During artificial photo-ageing, three polyurethanes, HDI-based polyurethane, MDI-based polyurethane and TDI-based polyurethane, have been considered to undergo UV radiation. Photochemical degradation of the polyurethanes has been monitored by means of Fourier transform infrared spectroscopy with attenuated total reflection accessory （FTIR-ATR）. It was proved that the mechanism of the photochemical degradation of polyurethanes might be the scissions of carbamate （urethane） groups and the re-reactions of radical groups formed in the scission reactions. From the experiment results HDI-based polyurethane, an aliphatic diisocyanate, could be considered to be more suitably used as relic protection materials among these three polyurethanes for its ageing products with less color.     

Preparation and characterization of functional group gradient surfaces

Functional group gradient surfaces where the density of functional groups changes gradually along the sample length were prepared. The functional group (? COOH, ? CONH₂, and ? OH group) gradient surfaces were produced by the treatment of low-density PE sheets using a corona with gradually increasing power, followed by the graft copolymerization of acrylic acid and subsequent substitution reaction of carboxylic acid groups to amide or hydroxyl groups. The prepared gradient surfaces were characterized by the measurement of water contact angle, FTIR-ATR, and ESCA. The gradient surfaces prepared can be used to systematically investigate the interactions of biological or other species in terms of the surface functional groups and their density of polymeric materials. © 1994 John Wiley & Sons, Inc.     

Analytical method development using FTIR-ATR and FT-Raman spectroscopy to assay fructose,sucrose, glucose and dihydroxyacetone,in Leptospermum scoparium nectar

The carbohydrate dihydroxyacteone (DHA) occurs in significant levels in Leptospermum scoparium (mānuka) nectar and is the precursor of methylglyoxyl (MGO), the unique non-peroxide antibacterial activity (NPA) component in mānuka honey. The nectar of ten different cultivars of L. scoparium was assayed quantitatively for fructose, glucose, sucrose, and DHA with high pressure liquid chromatography (HPLC) for comparison with FT-Raman and FTIR-ATR spectroscopic methods. FT-Raman spectroscopy and ATR-FTIR spectroscopy, alongside chemometric methods using principal component analysis (PCA) and partial least squares (PLS) prediction were shown to be useful techniques to quantify and compare the nectar composition in a range of cultivars of L. scoparium.