Alternative method for determining API degrees of petroleum in contaminated soil by FTIR

A method was developed to determine °API from the relative abundance of polar and aliphatic functional groups as measured by FTIR. Twenty-two samples of petroleum were collected from the southern region of Mexico and analyzed by FTIR using an Attenuated Total Reflectance (ATR) accessory. API gravity was run in parallel using the convention hydrometer method (ASTM D6822-12b). Variables were analyzed for principal components and a minimum of squares regression. API gravity of the petroleum used was between −8.8 and 41.5. For correlation, an index of the relative abundance of polar functional groups vs. saturates was developed. Data from calibration gave an R² = 0.9632 and a standard error of 0.0129, with an absolute error of 0.0104. During the validation (with petroleum from contaminated sites), the results gave an R² = 0.9024, with a standard error estimated at 0.0307 and an absolute mean error of 0.0199. Thus, the determination of API degrees of petroleum extracted from contaminated soil was shown to be viable using FTIR-ATR. The algorithm was developed to fit well for the whole range of crudes, from extra heavy (<10 °API) to super light (>39 °API) crudes. This method is simple, quick, does not require extensive sample preparation, uses very small sample proportions (<1 g) and produces only a minimum of waste as compared to the conventional (hydrometer) method.     

A rapid FT-NIR method for estimation of aflatoxin B1 in red chili powder

The feasibility of measuring Aflatoxin B₁ (AFB₁) in red chili powder was investigated by using Fourier transform near-infrared (FT-NIR) spectroscopy in diffuse reflectance mode combined with appropriate chemometric techniques. Aflatoxin free chili powder samples were spiked with known amount of AFB₁ ranging from 15 to 500 μg/kg and used for calibration model building based on partial least squares (PLS) regression algorithm. Different spectral preprocessing methods were investigated and optimized based on the lowest values of root mean square error of cross validation (RMSECV). Spectral wavenumber range of 6900.3–4998.8 and 4902.3–3999.8 cm^?1 and straight line subtraction preprocessing technique predicted AFB₁ content with best accuracy with lowest RMSECV = 0.654% and maximum correlation coefficient for validation plots (R² = 96.7). The overall results demonstrate that FT-NIR spectroscopy can be used for rapid, non destructive quantification of Aflatoxin B₁ in red chili powder.     

Effect of photosonication treatment on inactivation of total and coliform bacteria in milk

The combined effect of simultaneously applied acoustic energy and ultraviolet irradiation (UV-C), named photosonication, on the population reduction of total and coliform bacteria in raw milk was investigated. Photosonication was carried out at 100% (120 μm; 240 W) amplitude of ultrasound accompanied by UV light of 13.2 W cm^?2 while sonication was carried out at 100% amplitude without UV light. An ultrasonic processor (400 W and 24 kHz with a 22 mm diameter probe) and 3 ultraviolet lamps (4400 μW cm^?2 per lamp) were used. The exposure time was 15 min for all treatment, and samples were taken after 0, 3, 6, 9, 12 and 15 min. Thermal treatment (at 65 °C for 30 min) achieved a 3.29 log and 5.31 log-reduction for total and coliform bacteria, respectively. However, the reduction achieved was 4.79 log cfu mL^?1 and 5.31 log cfu mL^?1 for total and coliform bacteria, respectively, in photosonication while 1.31 log cfu mL^?1 and 4.01 log cfu mL^?1 for total and coliform bacteria, respectively in sonication. During photosonication, UV light contributed to an increase of lethality.     

Application of low-resolution Raman spectroscopy for the analysis of oxidized olive oil

The aim of this study was to evaluate the potential of low-resolution Raman spectroscopy for monitoring the oxidation status of olive oil. Primary and secondary oxidation parameters such as peroxide value, K₂₃₂ and K₂₇₀ were studied. Low-resolution Raman spectra ranging from 200 to 2700 cm^?1 in a set of 126 oxidized and virgin olive oil samples were collected directly using a probe. Partial Least Squares was used to calibrate the Raman instrument for the different targeted parameters. The performance of the models was determined by using validation sets, and the best results obtained were: R² = 0.91, RMSEP = 2.57 for the peroxide value content; R² = 0.88, RMSEP = 0.37 for K₂₃₂; and R² = 0.90, RMSEP = 0.08 for K₂₇₀. These results demonstrated that low-resolution Raman spectroscopy could be a relevant technique for evaluating the oxidation status of olive oils because the key oxidation parameters can be determined quickly and in a non-destructive and direct way.     

Spectrophotometric determination of erbium using kojic acid dye in different rare earth concentrates

A sensitive and selective spectrophotometric method was studied for the determination of erbium (Er) with kojic acid dye (koj) and cetylpyridinium chloride (CPC) as a cationic surfactant from Egyptian monazite and xenotime concentrates using third derivative spectrophotometry. The calibration curve was linear from 1 to 150?µg/mL erbium. The influence of various parameters and reaction conditions for optimum complex formation were investigated. The relative standard deviation for determination of 1?µg/mL erbium was found to be 1.5 after 5 repeated determinations with percentage error for Er determination from monazite and xenotime concentrates 6.4% and 4.48% respectively. The molar absorptivity of conventional and third derivative spectrum were 0.14?×?10³?M^?1?cm^?1 and 0.13?×?10³?M^?1?cm^?1 respectively and the detection limit was 1?µg/mL.     

PHOTOOXIDATION OF CORBETT FRACTIONS OF ASPHALT

ABSTRACT

Oxidation of asphalt causes the degradation and failure of asphalt pavement. Due to the molecular complexity and relatively high molecular weight of asphalt, the oxidation mechanism is complicated by the interactions among the molecules of different types. To minimize the interactions, the asphalt sample was chromatographically separated into saturates, naphthalene aromatics, polar aromatics, and asphaltenes. These Corbett fractions were then oxidized under ultraviolet irradiation. Fourier-transform infrared spectroscopy was used to analyze the structural changes of the Corbett fractions during photooxidation. All Corbett fractions have shown significant spectral changes in the region of 3500 ? 3100 cm^?1 characterized the stretching vibrations of hydroxyl or nitrogen-hydrogen groups, the peak around 1700 cm^?1 featured carbonyl groups, and in the region of 1320 ? 1000 cm^?1 characterized the formation of sulfur-containing functional groups. Strong evidence has shown that sulfates are produced in the oxidation of asphalt. The formation of sulfates provides an essential explanation for the deterioration of asphalt pavement.     

Estimating Methyl/Methylene Groups in Asphaltene and Other Fractions of Asphalt

Abstract

Infrared is the most widely used analytical method for interpreting the structure of petroleum fractions. In this study, IR spectra of standard normal nonadecane were used to get ε for methyl and methylene groups. A linear relationship was obtained by plotting the peak intensities at 2,954, 2,926, 2,854, 1,466, and 1,376 cm^?1 against different amounts of N-nonadecane. The R ² obtained for most of the plots was in the range of 0.988–0.997. The Beer-Lambert's law was used for the first time to quantitatively estimate the weight percent of methylene and methyl groups present in the different fractions of asphalt.     

Contamination levels for lead,cadmium and mercury in marine gastropods,echinoderms and tunicates

As part of a specific monitoring programme, total lead (Pb), cadmium (Cd) and mercury (Hg) concentrations in marine gastropods (common winkle, common whelk, abalone and murex), echinoderms (purple sea urchin and black sea cucumber) and tunicates (an ascidian species) were investigated by the French National Reference Laboratory (NRL) for trace elements in foodstuffs of animal origin. These elements were analysed by atomic absorption spectrometry in order to evaluate the safety of these species for human consumption. The highest levels of Hg and Cd were found in murexes, 0.185 mg kg^?1 and 0.853 mg kg^?1, respectively; whereas the highest level of Pb was detected in ascidians (0.505 mg kg^?1). Hg and Pb concentrations were always below the maximum levels set by the European legislation (0.5 mg Hg kg^?1 and 1.5 mg Pb kg^?1 wet mass) and for Cd, only 2 samples of murex (2.09 ± 0.42 mg kg^?1 and 2.33 ± 0.46 mg kg^?1) exceeded the maximum level set by French legislation of 2.0 mg kg^?1 wet mass.     

Loop-mediated isothermal amplification (LAMP) coupled with bioluminescence for the detection of Listeria monocytogenes at low levels on food contact surfaces

A commercial loop-mediated isothermal amplification (LAMP) based system with bioluminescence, named as 3M™ Molecular Detection Assay (MDA), was validated for the detection of Listeria monocytogenes (3-strain cocktail) at low levels (10⁰, 10¹, 10² CFU/100 cm²) inoculated on stainless steel (SS) and polyethylene (PE) surfaces, with and without (w/o) organic load (OL) of cold-smoked salmon homogenate by comparing with a standard ISO method as reference. The results of this study revealed that a commercial LAMP-based method performed equally effective compared with ISO method at inoculum levels of 10⁰ and 10²/100 cm², showing 100% specificity and sensitivity, respectively. At 10¹ CFU/100 cm², a slight reduction in the effectiveness of LAMP-based method was observed most likely due to the use of single enrichment step in the procedure of LAMP-based method. The LAMP-based method was shown to be rapid and reliable detection technique for L. monocytogenes present at low numbers on food processing surfaces, regardless of organic residues, and can be applicable in seafood industry.     

Feasibility of laser-induced breakdown spectroscopy (LIBS) as an at-line validation tool for calcium determination in infant formula

In this study, a 150 mJ laser-induced breakdown spectroscopy (LIBS) system was assessed to determine calcium content in infant formula (IF) samples. LIBS is a promising emission spectroscopic technique for elemental analysis, which offers advantages over conventional methods such as real-time analyses, little to no sample preparation and ease of use. The aim of this work was to evaluate the feasibility of LIBS as an at-line tool for IF manufacturing. To this end, IF mixtures with varying content of calcium were prepared over a range (approx. 1.5–7 mg/g of calcium) selected to be in conformity with the guidelines provided by the Codex Alimentarius Commission. Atomic Absorption Spectroscopy (AAS) was used as the reference method for mineral content determination in IF. Partial least squares regression (PLSR) was applied to the LIBS spectral data to develop a calibration model for calcium content quantification. A validation approach was then carried out to investigate the robustness of the model, which showed a good fit with values of R²_cv of 0.90 for cross-validation and a R²_p 0.85 for external validation. Low values for root mean square errors of cross-validation (RMSECV) and prediction (RMSEP) of 0.62 mg/g and 0.68 mg/g were obtained. Furthermore, this study also illustrated the possibility of LIBS to provide mineral prediction maps as a useful tool for testing sample homogeneity.     

Detection of acrylamide using a biodegradable zein-based sensor with surface enhanced Raman spectroscopy

In this study, a biodegradable zein/gold SERS platform was tested as a potential tool to detect acrylamide for the first time. It was found that the presence of acrylamide resulted in a characteristic marker SERS peak that did not exist in the background SERS spectrum of the sensor. This unique peak was at 1447 cm⁻¹. This peak was used to detect and quantify acrylamide in aqueous solutions and a calibration curve was obtained using acrylamide solutions within the range of 10 mg/ml and 10 μg/ml. After 10 μg/ml of concentration, it was not possible to make reliable measurements. The error or variation for each concentration in the range of 0.4 mg/ml (for 1 mg/ml) – 1.8 mg/ml (for 10 mg/ml) was observed. SERS was found to be an accurate technique for quantification purposes, in the concentration range studied. The calibration curve had an R² value of 0.93 and 0.97 (for log–log calibration curve). This was a proof-of-concept study to investigate the potential of a SERS sensor designed on a biodegradable platform and it was shown that this method can be potentially used with a careful design of acrylamide extraction from food samples.     

Antimicrobial films and coatings for inactivation of Listeria innocua on ready-to-eat deli turkey meat

Edible antimicrobial coating solutions incorporating chitosan, lauric arginate ester (LAE) and nisin were developed to reduce foodborne pathogen contamination on ready-to-eat (RTE) meats. RTE deli meat samples were directly coated with the solutions, or treated with solution-coated polylactic acid (PLA) films. The antimicrobial efficacy of the coatings and films against Listeria innocua inoculated onto the surface of RTE meat samples was investigated. Antimicrobial coatings with 1.94 mg/cm² of chitosan and 0.388 mg/cm² of LAE reduced L. innocua by ca. 4.5 log CFU/cm². Nisin (486 IU/cm²) showed less effectiveness than LAE (0.388 mg/cm²) and addition of nisin to the antimicrobial coatings or films containing LAE (0.388 mg/cm²) did not enhance the total antimicrobial effectiveness. Combining antimicrobial coatings or films with flash pasteurization (FP), which uses short burst of steam under pressure, further reduced L. innocua, achieving over a 5 log reduction. There was no significant difference in the effectiveness of antimicrobial films versus the coatings (p > 0.05). These data show the potential use of antimicrobial packaging alone, or in combination with FP, in preventing foodborne illness due to post-processing contamination of RTE meat products.     

Concentrations and dietary exposure to polycyclic aromatic hydrocarbons (PAHs) from grilled and smoked foods

We investigated the concentrations and profiles of 16 priority polycyclic aromatic hydrocarbons (PAHs) in various grilled and smoked foods and estimated the dietary exposure of Kuwaiti children, adolescent and adult populations. Results indicated that non-carcinogenic PAHs were present at high proportions (60–100%) with phenanthrene showing the highest mean concentration (54.9 μg kg^?1, 37.1% of the total PAH concentrations). Among the genotoxic PAHs (PAH8), chrysene (4.88 μg kg^?1, 3.29%) and benz[a]anthracene (2.27 μg kg^?1, 1.53%) showed the highest mean values. Meat tikka contained the highest mean concentrations of benzo[a]pyrene (BaP) (2.48 μg kg^?1), total genotoxic PAHs (42.9 μg kg^?1), total PAHs (ΣPAHs) (648 μg kg^?1) and total benzo[a]pyrene equivalents (ΣBaPeq) (6.02 μg kg^?1). High levels of genotoxic PAHs were detected in grilled vegetables (21.1 μg kg^?1), shish tauk (20.5 μg kg^?1) and whole grilled chicken (20.3 μg kg^?1) samples. However, meat and chicken shawerma samples had low levels of PAH8. Meat tikka (437 ng/day, 641 ng/day), whole grilled chicken (160 ng/day, 241 ng/day), grilled vegetables (120 ng/day, 166 ng/day), meat burger (114 ng/day, 92.7 ng/day) were the major contributors to the daily intake of PAH8 in children/adolescent and adult populations, respectively. The total mean dietary intakes for children/adolescents and adults for BaP (8.09 ng/day, 9.20 ng/day), PAH8 (84.2 ng/day, 95.7 ng/day), ∑PAHs (974 ng/day, 1108 ng/day) and ∑BaPeq (14.8 ng/day, 16.8 ng/day) were comparable. Cancer risks for Kuwaiti children/adolescents and adults from dietary intake of ΣBaPeq from the animal-origin foods were determined to be 2.63/10⁷ and 9.3/10⁷, respectively.     

Classification of intact açaí (Euterpe oleracea Mart.) and juçara (Euterpe edulis Mart) fruits based on dry matter content by means of near infrared spectroscopy

The processing of açaí (Euterpe oleracea Mart.) and juçara (Euterpe edulis Mart) fruit requires water addition for adequate pericarp extraction. Currently, the amount of added water is based on fruit moisture content as estimated using a convection oven method. In this study, diffuse reflectance FTNIR spectra (1000–2500 nm, 64 scans and spectral resolution of 8 cm⁻¹) of intact açaí and juçara fruit were used to discriminate fruit batches based on the dry matter (DM) content using mature fruit collected over two years. Spectra were collected of ∼25 fruits per batch, placed on a 90 mm diameter glass dish in a single layer. The calibration set contained of 371 lots, while the prediction set consisted of 132 lots (of different locations, times). Spectra were subject to several pre-processing methods and models were developed using Partial Least Squares Regression (PLSR), Partial Least Squares-Discriminant Analysis (PLS-DA) and Principal Component Analysis Discriminant Analysis (PCA-DA). A PLSR model constructed using the wavelength range of 1382–1682 nm and full multiplicative scatter correction achieved a root mean square error for prediction on DM of 5.25% w/w with a ratio of the standard deviation of DM set to the bias corrected RMSEP of 1.5 on the test set. A PCA-DA model based on the same wavelength of region outperformed the PLS-DA method to segregate the test population into categories of high (>32 %DM) and low DM (<32% DM) with 74% accuracy achieved. The PCA-DA technique is recommended to the processing industry as a non-destructive and rapid method for optimisation of water added during processing using batch assess of fruit from incoming lots of fruits.     

Ion selective electrodes based on methyl 6-(hydroxymethyl) picolinate ionophore for electrochemical determination of Fe(III) in petroleum water samples

A potentiometric method was described for the determination of iron(III) in petroleum water samples using modified carbon paste and screen-printed sensors. These sensors were embodied with multi-walled carbon nanotubes (MWCNTs) since it improved the performance of the sensors in presence of (methyl 6-(hydroxymethyl) picolinate) ionophore. The fabricated sensors can be applied successfully for the potentiometric determination of iron(III) ions in the concentration range of 1.0 × 10^?6–1.0 × 10^?2 mol L^?1 with a detection limit of 1.0 × 10^?6 mol L^?1 for modified carbon paste electrodes (MCPEs) and 2.6 × 10^?7–1 × 10^?2 mol L^?1 with a detection limit of 2.6 × 10^?7 mol L^?1 for the modified screen-printed electrode (MSPEs). The slopes of the calibration graphs were 19.9 ± 0.41 and 19.0 ± 0.16 for MCPEs with tricresylphosphate (TCP; electrode I) and dioctylsebacate (DOS; electrode II) as plasticizers, respectively. Also, the MSPEs showed good potentiometric slopes of 20.4 ± 0.30 and 19.6 ± 0.28 mV decade^?1 with tricresylphosphate (TCP; electrode III) and dioctylsebacate (DOS; electrode IV) as plasticizers, respectively. The sensors were successfully applied for the determination of Fe(III) in petroleum water samples. The results obtained applying these potentiometric sensors were comparable with those obtained using atomic absorption spectrometry (AAS).     

Simultaneous determination of type-A and type-B trichothecenes in barley samples by GC–MS

A validated method for the simultaneous determination of eight type-A and type-B trichothecenes in barley has been applied to the analysis of 44 samples from the 2007 harvest in Navarra (Spain). The procedure included simultaneous extraction of trichothecenes with acetonitrile and water (84:16), clean up with Multisep^® columns, derivatization of the extract and GC–MS analysis. During method validation, selectivity, linearity, precision and accuracy, limits of detection and quantification and recovery were evaluated. Recovery ranged from 92.0 to 101.9% (RSD < 15%), except for nivalenol (NIV) (63.1%), and the limits of detection and quantification ranged from 0.31 to 3.87 μg kg^?1 and from 10 to 20 μg kg^?1, respectively. The higher occurrence was found for deoxynivalenol (DON) (89% of the samples), although at concentrations below the maximum permitted level. The calculated dietary intakes of DON, NIV and the sum of T-2 and HT-2 were below the TDI values proposed. Two or more trichothecenes were present in 41% of the samples and so, the mycotoxin co-occurrence, and therefore synergic or additive effects, should be taking into account when determining permitted levels or risk assessment.     

Effects of UV-C on physicochemical quality attributes and Salmonella enteritidis inactivation in liquid egg products

The perspectives of UV-C radiation as a non-thermal treatment for liquid egg products were evaluated from the point of view of the effects on egg quality attributes and the decontamination efficiency against the main egg contaminant Salmonella enterica subsp. enterica Ser. Enteritidis. UV-C treated egg fractions (egg yolk, egg white and whole egg) were analyzed for changes in pH, color, temperature-dependent viscosity and TBARS index, and were inoculated with S. enteritidis (ATCC 13076). Contrary to heat treatments, UV-C was not affecting viscosity and pH. Browning due to Maillard was perceptible in egg yolk and whole egg at low UV-C doses, but the corresponding browning indexes were always lower than in heat pasteurized egg fractions. Major changes were only due to lipid oxidation. TBARS values at the highest UV-C doses were larger than in pasteurized egg yolk and whole egg; under dynamic conditions and 0.61 J cm^?2, results were not significantly different to natural untreated samples. And UV-C was effective to inactivate S. enteritidis. In egg white, a load reduction up to 5.3 log₁₀ was achieved under dynamic conditions (9.22 J cm^?2, 39 min), while 3.3 log₁₀ and 3.8 log₁₀ reductions were recorded in egg yolk and whole egg. Static treatments were less efficient, but still, load reductions between 1.7 and 2.8 log₁₀ were obtained. At 3.94 mW cm^?2, time necessary to achieve a 4D reduction of Salmonella cells was estimated to be around 7.4 min in egg white.     

PCDD,PCDF and PCB contamination in Atherina boyeri (Risso, 1810) from Turkey

The levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and indicator polychlorinated biphenyls were measured in Atherina boyeri (Risso, 1810) samples collected from Hirfanl? Dam Lake, Turkey in 2008 and 2009.Concentrations of PCDDs–PCDFs were detected as 0.16 and 0.17 pg TEQ₍₁₉₉₈₎ g^?1 wet weight while contamination levels of DL-PCBs were found as 0.42 and 0.38 pg TEQ₍₁₉₉₈₎ g^?1 wet weight in fish samples. The concentrations of total indicator PCBs in fish samples were found as 1.5 ng g^?1 and 0.9 ng g^?1 wet weight. Concentrations of PCDDs–PCDFs and DL-PCBs were below the EU regulation limits.     

DETERMINATION OF PARAFFINIC,NAPHTHENIC AND AROMATIC CARBON IN PETROLEUM DERIVED MATERIALS BY CARBON-13 NMR SPECTROMETRY

ABSTRACT

A carbon-13 NMR method gives results for paraffinic, naphthenic, and aromatic carbon which compare well with those obtained from ASTM D2140. In order to be fully applicable for analysis by NMR, the sample must be of natural origin - preferably petroleum, shale oil or tar sands - and boil above about 200^°C. Otherwise, the samples may have been processed or separated by any method. The rationale for the present method, the restricted applicability of other NMR methods, and prospects for further detailed information on carbon functional groups are discussed.     

Antimicrobial effect of acidified sodium chlorite,sodium chlorite,sodium hypochlorite,and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro

Fresh-cut cilantro is particularly susceptible to microbial growth and, therefore, use of an effective sanitizer on this product is of great importance. The objective of this study was to evaluate the efficacy of different sanitizing treatments on reducing Escherichia coli O157:H7 populations, aerobic mesophilic bacterial, yeast and mould counts on fresh-cut cilantro. Cut cilantro was treated with sodium hypochlorite (SH) at 0.2 g L^?1 free chlorine and acidified sodium chlorite (ASC) at 0.1, 0.25, 0.5 and 1 g L^?1, along with the components of ASC, i.e., citric acid (CA) at 6 g L^?1 and sodium chlorite (SC) at 1 g L^?1. In the present study, it was found that SH inactivated, at maximum, 1–1.3 log cfu g^?1 of background or pathogenic microflora present on cut cilantro. However, reductions of more than 3 log cfu g^?1 were observed after washing with 1 g L^?1 of ASC. Moreover, when lower concentrations of ASC were used (0.25 and 0.5 g L^?1), microbial populations were reduced by about 2 log cfu g^?1. SC was as effective as ASC at 1 g L^?1 in reducing aerobic mesophilic bacteria and E. coli O157:H7 populations, although it was not as effective as ASC in reducing yeast and mould populations.