Fourier Transform Infrared Method Research Articles

Biomolecular transitions and lipid accumulation in green microalgae monitored by FTIR and Raman analysis.

Fourier transform infrared (FTIR) and Raman spectroscopic techniques were employed to analyze the biomolecular transitions and lipid accumulation in three freshwater green microalgal species, Monoraphidium contortum (M. contortum), Pseudomuriella sp. and Chlamydomonas sp. during various phases of their growth. Biomolecular transitions and lipid [hydrocarbons, triacylglycerides (TAGs)] accumulation within the microalgal cells were identified using second derivatives of the FTIR absorption spectroscopy. Second derivative analysis normalized and resolved the original spectra and led to the identification of smaller, overlapping bands. Both relative and absolute content of lipids were determined using the integrated band area. M.contortum exhibited higher accumulation of lipids than the other two species. The integrated band area of the vibrations from saturated (SFA) and unsaturated lipids (UFA) enabled quantification of fatty acids. The percentage of SFA and UFA was determined using GC, FTIR and Raman spectroscopy. From the spectral data, the order of increasing concentration of SFA among the three microalgal species was M.contortum > Chlamydomonas sp. >Pseudomuriella sp. The spectral results on fatty acids were consistent with the separation of lipids by gas chromatography. The results emphasized the significance of FTIR and Raman spectroscopic methods in monitoring the biomolecular transitions and rapid quantification of lipids, without the need for extraction of lipids.

Numerical and Experimental Assessment of a Novel Multinozzle Burner with CO2 Diluent to Improve the Emissions from a Swirling Flame in a Combustion Chamber

As turbulent combustion is commonly used in industrial applications, in this study, a new burner is designed in order to be applied in a test furnace. With the employment of Fourier transform infrared (FTIR) spectroscopy, the species in the flue gas at different ratios of direct secondary air flow and swirling secondary air flow are detected to choose the optimum ratio for the subsequent experiments. An experimental investigation is performed to study the effects on a CH₄/air swirling turbulent flame while mixing CO₂ with CH₄ as the fuel. The OH-PLIF (hydroxyl-planar laser-induced fluorescence) and FTIR methods were employed to measure the OH distribution and NO in the flue gas separately with the added CO₂. To study the reaction mechanism and predict the flow, temperature fields, and NOₓ emissions, numerical modeling works have been performed employing the COMMENT code. The standard k–e and Reynolds stress model turbulence models are used to describe the turbulent flow. The “eddy dissipation” model (6 species and 2 reactions), the PDF (probability density function) model (β function) (9 species and 8 reactions) with a chemical equilibrium model, and the laminar flamelet model (17 species and 46 reactions) are used for modeling the turbulence–chemistry interaction. The NOₓ postprocessor is used to predict the NO emissions. The concentrations of the OH and O radicals are obtained by assuming the hypothesis of partial equilibrium and using a PDF in terms of temperature. Several factors influencing the combustion process are investigated. From the experiments, it was found that the OH and NO production both increased first, reached a peak value when the fraction of CO₂ was 25%, and then decreased. The numerical results obtained are compared with the experimental results and the results from previous works, and the experimental and numerical results are found to be in good agreement.

Applications of Fourier transform infrared spectroscopic method for simultaneous quantitation of some hypoglycemic drugs in their binary mixtures.

Cost-effective, green, simple and reliable transmission Fourier-transform infrared (FTIR) spectroscopic method was developed for simultaneous analysis of hypoglycemic drugs in their binary mixtures for the first time. The FTIR method was applied for the determination of vildagliptin (VILD), glimepiride (GLIM) and pioglitazone (PIOG) in binary mixture with metformin (METF). The method was validated according to the International Conference on Harmonization (ICH) guidelines. The obtained results (expressed in peak areas) are linear with concentration in the range of 0.61-20, 0.26-24 and 0.37-4 μg/mg for VILD, PIOG and GLIM, respectively while the linearity ranges for METF were 0.40-200, 0.26-800 and 0.19-1000 μg/mg with VILD, PIOG and GLIM, respectively. The limits of detection (LODs) were 0.20, 0.08 and 0.12 μg/mg for VILD, PIOG and GLIM, respectively while METF LODs were 0.13, 0.08 and 0.06 μg/mg with VILD, PIOG and GLIM, respectively. The FTIR method has been successfully applied for the determination of the cited binary mixtures in its pharmaceutical tablets and the obtained results showed satisfactory % recovery.

Effects of Isotopic Calibration Gases on IR Quantification Analyzer Techniques to Measure CO and CO <sub>2</sub> in Engine Emissions Testing

<div class="section abstract"><div class="htmlview paragraph">Infrared spectroscopic methods are the most common methods in the automotive industry for measuring carbon monoxide (CO) and carbon dioxide (CO<sub>2</sub>) gases. Concentrations of both gases, which are emitted from the combustion of fuels, are required to be determined accurately in order to follow strict environmental regulations. Appropriate analytical techniques and accurate calibration gas mixtures are therefore critical for successful measurements. Regulatory documents such as the EPA’s Code of Federal Regulations 40 (CFR 40) part 1065.250, UN ECE-R83, and (EU) 2017/1151 recommend a nondispersive infrared (NDIR) analyzer to measure CO and CO<sub>2</sub> concentrations in raw or diluted exhaust gas samples. Over the last decade, Fourier Transform Infrared (FTIR) spectrometry has been validated and recommended in engine exhaust certification testing as well as in engine and vehicle development activities.</div><div class="htmlview paragraph">The variation in the isotopic ratio of <sup>13</sup>C/<sup>12</sup>C in natural atmospheric CO<sub>2</sub> is in the range of ± 2‰ however, artificial or non-natural sources of CO or CO<sub>2</sub> can potentially have much larger variances. To fully understand the impacts of isotopic composition on the analyzers, the δ<sup>13</sup>C values used in this study were selected to cover a broad range of non-natural isotope ratios (very depleted and enriched). In the present work on both FTIRs and NDIRs, up to 4% deviation in analytical results were observed relative to the base case composition (-12‰ <sup>13</sup>CO) when the CO/N<sub>2</sub> gas mixture was enriched to 2630‰ with <sup>13</sup>C content. Analytical deviations measured on NDIR analyzers were more pronounced (4-14%) relative to the base case composition with the change of <sup>13</sup>C in the CO<sub>2</sub>/N<sub>2</sub> mixture from -982‰ to 6783‰. Moreover, the error with FTIR measurements could rise up to a factor of 2 or more depending on the <sup>13</sup>C and <sup>12</sup>C band selection and their evaluation methods. Known isotopic gas mixtures and careful evaluation band selection in the FTIR method were observed to reduce the analytical errors. Even though calibration gases were prepared accurately for molecular concentrations, carbon isotopic concentrations far removed from natural abundance showed significant errors in the measurements. It is therefore essential to have either known or natural ratios of carbon isotope calibration gas mixtures for accurate emission measurements.</div></div>

Direct Measurement of Zeolite Brønsted Acidity by FTIR Spectroscopy: Solid-State 1H MAS NMR Approach for Reliable Determination of the Integrated Molar Absorption Coefficients

Fourier transform infrared (FTIR) spectroscopy is broadly applied nowadays for probing the concentration and strength of acid sites in zeolite catalysts. Accuracy of direct determination of the quantity of different hydroxyl groups by FTIR method suffers from uncertainty of the integrated molar absorption coefficients, e. The values of e reported by different authors might differ by an order of magnitude. This paper provides an approach for reliable determination of the integrated molar absorption coefficients by combining 1H magic-angle spinning (MAS) NMR and FTIR spectroscopy techniques. The concentration of Bronsted acid sites for the series of H-ZSM-5 and H-ZSM-23 zeolite samples with different Si/Al ratio has been reliably established with 1H MAS NMR using methane and benzene as internal standards adsorbed on the studied samples. The data on the obtained concentration were further used to analyze same zeolite samples with FTIR spectroscopy and derive the information on the values of the integrated mo...

A comparison of respirable crystalline silica concentration measurements using a direct-on-filter Fourier transform infrared (FT-IR) transmission method vs. a traditional laboratory X-ray diffraction method

Evaluation and control of respirable crystalline silica (RCS) exposures are critical components of an effective mine industrial hygiene program. To provide more timely exposure data in the field, an end-of-shift Fourier transform infrared (FT-IR) spectrometry method has been developed for evaluation of direct-on-filter RCS. The present study aimed to apply this FT-IR method using field samples collected in three Northwestern U.S. metal/nonmetal mines and compare the results to traditional laboratory X-ray diffraction analysis (XRD). Seventy-five dust samples were analyzed using both methods. Samples for each mine were split in half by random assignment, with half used to create a calibration factor for the FT-IR analysis and half used to apply the calibration. Nonparametric correlational and two-sample comparative tests were used to assess the strength of association and the level of agreement between the two methods. Strong, positive correlations were observed between FT-IR and XRD RCS concentrations, with Spearman rank correlation coefficients ranging between 0.84 and 0.97. The mean RCS concentrations determined through FT-IR analysis were lower than through XRD analysis, with mean differences ranging from −4 to −133 ug/m3 and mean percent errors ranging from 12% to 28%. There was a statistically significant improvement in the level of agreement between log FT-IR and log XRD RCS concentrations following calibration at two of the three mines, with mean differences of −0.03 (p = 0.002) and −0.02 (p = 0.044) in the log scale. The reduction in mean difference following calibration at the other mine was not statistically significant (mean log scale difference = −0.05, p = 0.215), but the differences between FT-IR and XRD were not significantly different without calibration (mean log scale difference = −0.07, p = 0.534). The results indicate that mine-specific calibration factors can improve the level of agreement between RCS concentrations determined via a field-based, end-of-shift FT-IR method in metal/non-metal mines as compared to traditional XRD analysis.

Enhanced production of phenolic compounds in hairy root cultures of Polygonum multiflorum and its metabolite discrimination using HPLC and FT-IR methods.

Hairy root cultures (HRCs) are characterized by fast and unlimited root growth, and they have greater genetic stability than other cultivation methods. HRCs are known to accumulate phytochemical levels comparable to those of intact plant. In this study, HRCs of Polygonum multiflorum were established from leaf explants infected with Agrobacterium rhizogenes strain KCCM 11879. Over 60% of the explants showed hairy root induction after 21days of cultivation on hormone-free MS (Murashige and Skoog Physiol Plant 15:473-479, 1962) medium; induced roots were confirmed by PCR using a rolC-specific primer. Of the six lines of HRCs selected for further analysis, line HR-01 performed best, producing a root biomass (105.2gL-1 of FW, 9.7gL-1 of DW), which is 10-fold higher than that of non-transgenic roots. The HR-01 line also showed a significant increase in its total phenolic content (26.64mgg-1 DW), while non-transgenic roots accumulated 8.36mgg-1 DW of total phenolic. The levels of phenolic compounds in the HRCs increased more than 2.5-fold following exposure to 50μM methyl jasmonate for 5days. Fourier transform infrared (FT-IR) spectroscopic analysis of bioactive accumulation in P. multiflorum enabled discrimination between hairy root and adventitious root cultures. Thus, it is evident from this study that HRCs could be an attractive proposition for large-scale production of root biomass and secondary metabolites of P. multiflorum in bioreactors.

Polymorphic forms of bisoprolol fumarate

Bisoprolol fumarate is a beta blocker-type drug substance which has been well known for several decades. However, no relevant data can be found in the literature about its crystal polymorphism. The purpose of this paper was to present two anhydrous forms (Form I and Form II) and a hydrate of bisoprolol fumarate substance. Crystalline forms were studied by various solid-state analytical methods: Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRPD), dynamic vapor sorption (DVS) and thermoanalytical methods (thermogravimetry and differential scanning calorimetry). Thermodynamic stability and solubility of the presented polymorphs were also investigated. Both FT-IR and XRPD methods were found to be suitable for the characterization of the different crystal structures. Thermoanalytical measurements showed that (1) Form I and Form II own clearly different melting points and (2) both Form II and hydrate forms can transform into Form I at higher temperature values. Results of the DVS measurements prove that both Form I and Form II became metastable under extremely humid conditions (> 80% RH) and converted into the hydrate. Thermodynamic stability studies showed that Form I and Form II polymorphs are in enantiotropic relationship with an enantiotropic point at about 40–45 °C. Solubility studies indicated that all of the prepared forms are highly soluble, and no difference was found between them. Considering the recommendations of the corresponding International Conference of Harmonization guideline, it can be stated that no specification is required for crystal polymorphism in case of this substance.

Structural Elucidation of Peanut, Sunflower and Gingelly Oils by Using FTIR and 1H NMR Spectroscopy

Aims: The present study focused on FTIR and 1H-NMR spectroscopic methods to assign structural connectivity and purity of the oils. Methods: Non-destructive Fourier Transform Infrared (FTIR) and 1H nuclear magnetic resonance (1H-NMR) spectroscopy techniques are used to assign the structural confirmation of the triacylglyceride (TAG) functional component in three different oils namely Sunflower, Peanut, and Gingelly oils respectively. Results: FTIR spectrum shows a very high intense band at 1744 cm-1 associated with the existence of the ester carbonyl functional group (O-C=O) and very weak shoulder peak of cis double-bond (C=C) stretching was noticed at ∼1655 cm-1. In 1H-NMR spectrum shows well resolved chemical shift values in the range 5.3-0.8 ppm corresponding to characteristic group in aliphatic region. Conclusion: Each distinct peak was determined based on chemical shift as well as splitting pattern values. For olefin signal as triplet, tertiary methine protons as singlet, well separated oxymethylene seen as triplet at ~4.2 ppm owing to presence of high electronegative oxygen atom connected to methylene chain gives more deshielding effect. As for bis-allylic, α-carbonyl methylene, β-carbonyl methylene, allylic, saturated methylene along with terminal methyl proton signals are noticed in the span of 2.3-0.8 ppm. A remarkable feature of the spectra is well resolved chemical shift values is clearly support presence of longer hydrocarbon chains. Absence of multiplet coupling peaks and disappearance of signals in down shield region > 5.4 ppm confirms the absence of trans stereoisomer (E-conformation), aromatic and heterocyclic epoxide compounds.

Multidisciplinary Investigation of the Imperial Gates of the 17th Century Wooden Church in Sălișca, Cluj County, Romania

One of the most beautiful elements of cultural heritage in Romanian villages is the Transylvanian wooden churches. Unfortunately, these heritage elements have experienced considerable deterioration. This paper presents the results of a project whose main goal was the scientific investigation of the Imperial Gates belonging to the wooden church in Sălișca, Cluj County, Romania. To digitally preserve and document the Imperial Gates, a scientific investigation into the wooden support and the painting materials (ground, pigments) were performed using Fourier transform infrared (FTIR) and x-ray fluorescence (XRF) spectroscopy. FTIR spectroscopy provided information about the wooden support, whereas XRF and FTIR methods were used to structurally characterize the painting materials. These structural data were correlated with the artistic, theological, and historical analysis of the religious heritage monument. Starting from the information acquired about the wooden support and the painting materials, the Imperial Gates were three-dimensional (3D) scanned using state-of-the-art laser scanners. The digitization of the Imperial Gates and the interior of the church was performed to maintain the current preservation status and disseminate this information to the public using online instruments.

Wild Boar Fat Analysis in Beef Sausage Using FTIR Method (Fourier Transform Infrared) Combined with Chemometrics

Background: Sausage is ready to eat meals for children, adolescents, and older adults. The meat contained in a beef sausage might not be consistent to the one listed on the label. Fourier Transform Infrared (FTIR) spectroscopy combination with a chemometric method is one of the most used methods to detect wild boar fat with rapid and consistent results. Results of analysis can classify fatty acid composition contained. Objective: The aim of this study is to determine the fat profile in sausage samples and differentiate the grouping of wild boar fat and beef fat in sausage preparation. Methods: The study was designed by making 7 different variations of wild boar reference sample concentrations, which were 100%, 75%, 65%, 50%, 35%, 25% and 100% beef. Six other samples were gathered from various street vendors. The results were analyzed using FTIR spectroscopy combined with chemometric with Partial Least Square (PLS) and Principal Component Analysis (PCA). Result: The results of analysis using Horizon MBTM apps showed optimal wave number within 1250-900 cm-1. The results of calibration with equation y= 0.994x + 0.334 and the value of (R2) determination was 0.998, and root mean square error of calibration (RMSEC) was 1.22%. The results of validation using parameter value of root mean square error of cross validation (RMSECV) 2.68%, and root mean square error of prediction (RMSEP) was 0.11%. Conclusion: PCA result showed that five from six samples possibly have same physical and chemical properties similar to fatty beef sausage.

Rapid and Simultaneous Determination of the Iodine Value and Saponification Number of Edible Oils by FTIR Spectroscopy

A rapid method is developed to facilitate the Fourier transform infrared (FTIR) spectroscopy analysis of edible oils using disposable polyethylene (PE) films as sample support for the determination of the iodine value (IV) and saponification number (SN). For direct IV analysis, quantification is achieved using the cis and trans double band region (3206–2992 cm−1) by a partial least squares calibration model, whereas, SN is directly determined using the area in carbon chain skeleton vibration absorption region (781–650 cm−1). The proposed method is applicable to various edible oils ranging in IV from 7.0 to 190.0 g 100 g−1 and SN from 162.7 to 222.0 mg g−1 with good precision and accuracy (relative standard deviations 0.39 and 0.32%, respectively) relative to the AOCS standard methods but with markedly less sample preparation and analytical effort.Practical Applications: Standard titration methods for determining the IV and SN of edible oils are labor intensive and require complex solvents and reagents. The PE‐film‐based FTIR method is more sensitive than attenuated total reflectance‐FTIR method and free from problems associated with the viscosity of oils, which is practical and easy to operate. The method can further simplify and facilitate simultaneous FTIR IV and SN analyses and is applicable to various edible oils over a wide range.A PE‐film‐based FTIR method is developed to determine the iodine value (IV) and saponification number (SN) of edible oils. The regions 3206–2992 cm−1 and 781–650 cm−1 are selected for IV and SN analysis, respectively. In the graphical abstract the IV and SN calibration and validation figures are presented.

Non-destructive Analysis of Food Adulteration and Legitimacy by FTIRTechnology

Despite of old methods, an emerging technology of Fourier Transform Infrared (FTIR) spectroscopy has been appeared to use as a promising application for the detection of adulteration in food. FTIR method works on the principal of interaction of electromagnetic radiations with the molecules of specific food with defined energy. In this review, the three regions of electromagnetic spectra including near infrared, mid infrared and far infrared are the points of spotlight. For food industry, FTIR method is expedient, automatic, time saving and most importantly, it shows non-destructive analysis of food physically as well as chemically. Moreover, FTIR in collaboration with the authentic commendable data analytical system appeared as a tremendous appeal for descriptive test of food from extremely large quantity to its trivial component level, showing dramatically potential for adulteration analysis with the substantial contrivance for the quality control progressions. A systematic review of literaturehas been performed to amass the information of FTIR technique as non destructive method for analysis of intentionally added harmful chemicals from existing research publications.

A New Method for Determining the Concentration of Electrolyte Components in Lithium-Ion Cells, Using Fourier Transform Infrared Spectroscopy and Machine Learning

A new method is introduced for determining unknown concentrations of major components in typical lithium-ion battery electrolytes. The method is quick, cheap, and accurate. Machine learning techniques are used to match features of the Fourier transform infrared (FTIR) spectrum of an unknown electrolyte to the same features of a database of FTIR spectra with known compositions. With this method, LiPF6 concentrations can be determined with similar accuracy and precision as an inductively coupled plasma optical emission spectrometry (ICP-OES) method. The ratios of organic carbonate solvent species can be determined with more rapidity than gas chromatography (GC). This FTIR method is faster and less expensive than GC and ICP-OES, and has the added benefit of being able to determine LiPF6 concentration and solvent fractions simultaneously. Application of this tool can facilitate electrolyte analysis of aged lithium-ion cells, and will help elucidate mechanisms for cell degradation.

Structural, morphological and electrical properties of multi-doped calcium phosphate materials as solid electrolytes for intermediate temperature solid oxide fuel cells

Modified solution precipitation method was used to prepare pure and doped Mg, Sr and Na hydroxyapatite type materials (CaP, CaMgP and CaSrNaP). Modification consisted of partial substitution of nitrates by acetate solution in order to achieve a more soluble and cost effective synthesis. The obtained samples were calcined at 400?C (CaP400, CaMgP400 and CaSrNaP400). All powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Calcined samples were densified at 1000?C in an air for 3 h (CaP1000, CaMgP1000 and CaSrNaP1000). Sintered samples were characterized by XRPD, FTIR, SEM, EDS and complex impedance methods. The highest conductivity was found for the multi-doped phosphate sample (CaSrNaP1000) at 700?C (1.90?10-3?-1cm-1). The corresponding activation energies of conductivity amounted to 0.31 eV in the temperature range 500-700?C.

Comparison and validation of Fourier transform infrared spectroscopic methods for monitoring secondary cell wall cellulose from cotton fibers

The amount of secondary cell wall (SCW) cellulose in the fiber affects the quality and commercial value of cotton. Accurate assessments of SCW cellulose are essential for improving cotton fibers. Fourier transform infrared (FT-IR) spectroscopy enables distinguishing SCW from other cell wall components in a rapid and non-invasive way. Thus it has been used for monitoring SCW development in model plants. Recently, several FT-IR methods have been proposed for monitoring cotton fiber development. However, they are rarely utilized for assessing SCW cellulose from cotton fiber due to limited validation with various cotton species grown in different conditions. Thus, we compared and validated three FT-IR methods including two previously proposed methods analyzing entire spectra or specific bands as well as a new method analyzing FT-IR spectral regions corresponding to cellulose with various cotton fibers grown in planta and in vitro. Comparisons of the FT-IR methods with reference methods showed that the two FT-IR methods analyzing the entire spectra or cellulose regions by principal component analysis monitored SCW qualitatively, whereas the FT-IR method analyzing specific bands (708, 730, and 800 cm−1) by a simple algorithm allowed the monitoring of SCW cellulose levels quantitatively. The quantitative FT-IR method is a potential substitute for lengthy and laborious chemical assays for monitoring SCW cellulose levels from cotton fibers, and it can be used for a better understanding of cotton fiber SCW development and as a part of the quality assessment tools used to guide choices for improving fiber quality.

Multilevel profiling and identification of Dalbergia odorifera and Dalbergia stevensonii by FTIR, NMR and GC/MS

As a rare and valuable wood and herbal material, Dalbergia odorifera is often counterfeited by Dalbergia stevensonii in the market. For the confident chemical identification of D. odorifera and D. stevensonii, the ethanol-benzene extractives are characterized by multiple metabolomics tools, including Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC/MS). Conventional FTIR spectroscopy, second derivative infrared (SD-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy are combined to interpret the functional groups of the ethanol-benzene extractives. Fingerprint-like characteristics make FTIR a rapid and accurate method to distinguish D. odorifera from D. stevensonii. Chemical differences of the extractives revealed by FTIR methods can be further confirmed by 1H NMR and 13C NMR. Meanwhile, the volatile compounds in the extractives can be identified by GC/MS. The combination of FTIR, NMR and GC/MS makes it possible to obtain the multiple profiles of the ethanol-benzene extractives, which is essential for the confident chemical identification of D. odorifera and D. stevensonii.

The prediction of bitumen properties based on FTIR and multivariate analysis methods

The aim of this research was to correlate the chemical and physical characteristics of bitumen samples with the Fourier Transform infrared (FTIR) spectroscopy. Based on the FTIR analyses of 32 bitumen samples of different refineries, viscosity and ageing states using the attenuated total reflection (ATR) technology with multiple reflections, the gained spectra were evaluated with the chemometrical approach including multivariate analysis methods. With the Linear Discriminant Analysis (LDA), the bitumen samples could be distinguished according to the refinery even if the grades and the ageing states of the samples varied. In addition, the Partial Least Square Regression (PLSR) enables the determination of linear combinations for the description of different chemical, conventional and rheological parameters including the asphaltene content casp, the softening point TR&B, the needle penetration PEN, the complex shear modulus |G∗| and the phase angle δ. Thereby, the separated consideration of the refineries allows the prediction of the parameters within the permitted limits according to the respective standards. Only for the softening point, the deviation of the calculated values exceeds the permitted deviations.

Development of a New Method for Analysis of Oil Mists

Background: Mineral oils, a complex mixture of chemicals, are primarily used in metalworking processes. Due to different toxicity levels found in mineral oils, two threshold limit values are given for the evaluation of mists of highly and poorly refined mineral oil. Objectives: The objective of this study was to explore a new method for the analysis of 2 classes of mineral oils by the FT-IR. Methods: Highly and poorly refined mineral oil samples were prepared by spiking the filters in the range of 10 to 2,250 µg/sample. Samples were extracted with 10 mL of carbon tetrachloride, subsequently analyzed by Fourier Transform Infrared (FT-IR) in the region of 3031 to 2,796 cm-1. Mineral oils (highly and poorly refined) were distinguished qualitatively, according to the FT-IR spectroscopy to determine the presence of formaldehyde using functional groups C = O and C - H, N-Nitroso compounds, and functional groups of N-N and N = O. Method validation parameters, such as precision, accuracy, detection limit and comparison of identical samples with the reference method by NIOSH No.5524 were considered. Results: According to the FT-IR spectroscopy in this study, highly and poorly refined mineral oil samples were distinguished according to their spectral absorption of the functional groups. The FT-IR spectroscopy analyzed highly and poorly refined mineral oil samples in the linear range of 10 to 2,250 µg/sample. The coefficient variations of inter-day and intra-day were 3.61 and 5.08 for highly refined mineral oil, and 5.23 and 5.18 for poorly refined mineral oil, respectively. The average accuracies for highly and poorly refined oil samples were 1.4% and 0.54%, respectively. Conclusions: The statistical average differences in the results drawn from the FT-IR method and actual spiked samples were significantly lower than the differences measured by the NIOSH No.5524 method and spiked samples. Therefore, this study demonstrates a viable alternative method for the analysis of mineral oils in future studies.

Synthesis of Bioactive Chlorogenic Acid-Silica Hybrid Materials via the Sol-Gel Route and Evaluation of Their Biocompatibility.

Natural phenol compounds are gaining a great deal of attention because of their potential use as prophylactic and therapeutic agents in many diseases, as well as in applied science for their preventing role in oxidation deterioration. With the aim to synthetize new phenol-based materials, the sol–gel method was used to embed different content of the phenolic antioxidant chlorogenic acid (CGA) within silica matrices to obtain organic-inorganic hybrid materials. Fourier transform infrared (FTIR) measurements were used to characterize the prepared materials. The new materials were screened for their bioactivity and antioxidant potential. To this latter purpose, direct DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) methods were applied: radical scavenging capability appeared strongly dependent on the phenol amount in investigated hybrids, and became pronounced, mainly toward the ABTS radical cation, when materials with CGA content equal to 15 wt% and 20 wt% were analyzed. The in vitro biocompatibility of the synthetized materials was estimated by using the MTT assay towards fibroblast NIH 3T3 cells, human keratinocyte HaCaT cells, and the neuroblastoma SH-SY5Y cell line. As cell viability and morphology of tested cell lines seemed to be unaffected by new materials, the attenuated total reflectance (ATR)-FTIR method was applied to deeply measure the effects of the hybrids in the three different cell lines.