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1.
Batsoulis AN Nacos MK Pappas CS Tarantilis PA Mavromoustakos T Polissiou MG 《Applied spectroscopy》2004,58(2):199-202
Hemicellulose samples were isolated from kenaf (Hibiscus cannabinus L.). Hemicellulosic fractions usually contain a variable percentage of uronic acids. The uronic acid content (expressed in polygalacturonic acid) of the isolated hemicelluloses was determined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and the curve-fitting deconvolution method. A linear relationship between uronic acids content and the sum of the peak areas at 1745, 1715, and 1600 cm(-1) was established with a high correlation coefficient (0.98). The deconvolution analysis using the curve-fitting method allowed the elimination of spectral interferences from other cell wall components. The above method was compared with an established spectrophotometric method and was found equivalent for accuracy and repeatability (t-test, F-test). This method is applicable in analysis of natural or synthetic mixtures and/or crude substances. The proposed method is simple, rapid, and nondestructive for the samples. 相似文献
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SA Petropoulos D Daferera CA Akoumianakis HC Passam MG Polissiou 《Journal of the science of food and agriculture》2004,84(12):1606-1610
Essential oils obtained by simultaneous distillation–extraction (SDE) from leaves, petioles and roots of three types of parsley (turnip‐rooted, plain leaf and curly leaf type), sown on three different dates, were analysed by GC‐MS (gas chromatography–mass spectrometry) analysis. Parsley plants were found to produce mainly β‐phellandrene, 1,3,8‐p‐menthatriene, α‐,p‐dimethylstyrene, myristicin, β‐myrcene and apiole. In some cases α‐ and β‐pinene were also found, whereas β‐elemene was detected, especially in the curly leaf type. The growth stage, plant tissue and date of sowing, as well as the climate conditions, all had a significant effect on the essential oil composition by altering the ratio of the above substances. Copyright © 2004 Society of Chemical Industry 相似文献
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E. Anastasaki C. Kanakis C. Pappas L. Maggi C. P. del Campo M. Carmona G. L. Alonso M. G. Polissiou 《European Food Research and Technology》2010,230(4):571-577
Mid-infrared spectroscopy combined with multivariate analysis has been applied for the discrimination of 250 saffron samples
from Greece (40 samples), Iran (87 samples), Italy (60 samples) and Spain (63 samples). The infrared spectra of saffron filament
samples and their organic extracts were recorded. Principal component analysis was applied to different spectral regions.
Then the principal components were used as variables in discriminant analysis. The best discriminatory approach was achieved
in the spectral region 2000–700 cm−1. The spectral region responsible for the differentiation of Italian samples is in the region of carbonyl group around 1746 cm−1. The spectral region at around 1600 cm−1 and the band at 1670 cm−1 are responsible for the differentiation of samples from the remaining countries. From the original grouped cases, 93.6% were
correctly classified. The correct classification rates for saffron samples from Greece, Iran, Italy and Spain were 90.0, 89.5,
96.7 and 98.4%, respectively. The combination of infrared spectroscopic technique with multivariate analysis is a rapid and
ambient method to discriminate saffron samples in terms of geographical origin. 相似文献
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C.S. Pappas P.A. Tarantilis E. Moschopoulou G. Moatsou I. Kandarakis M.G. Polissiou 《Food chemistry》2008
A new methodology for identification and differentiation of goat and sheep milk was developed based on FT-IR spectroscopy using hierarchical and discriminant analysis. Forty-nine goat and 38 sheep defatted and freeze-dried Greek milk samples were analyzed. FT-IR spectra were obtained in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) mode. The spectral region 1840–950 cm−1 was used to ‘fingerprint’ milk types. Main peak used for differentiation of goat/sheep milk is located at 1745 cm−1, which is correlated to the degree of sugars carboxyl methyl esterification. Hierarchical and discriminant analyses were based on the absorptions of the above spectral region. These analyses showed that the samples of goat milk can be differentiated from the samples of sheep’s. 相似文献
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ULTRA: A Unique Instrument for Time-Resolved Spectroscopy 总被引:2,自引:0,他引:2
Greetham GM Burgos P Cao Q Clark IP Codd PS Farrow RC George MW Kogimtzis M Matousek P Parker AW Pollard MR Robinson DA Xin ZJ Towrie M 《Applied spectroscopy》2010,64(12):1311-1319
We report the development of a high-sensitivity time-resolved infrared and Raman spectrometer with exceptional experimental flexibility based on a 10-kHz synchronized dual-arm femtosecond and picosecond laser system. Ultrafast high-average-power titanium sapphire lasers and optical parametric amplifiers provide wavelength tuning from the ultraviolet (UV) to the mid-infrared region. Customized silicon, indium gallium arsenide, and mercury cadmium telluride linear array detectors are provided to monitor the probe laser intensity in the UV to mid-infrared wavelength range capable of measuring changes in sample absorbance of ΔOD ~ 10(-5) in 1 second. The system performance is demonstrated for the time-resolved infrared, two-dimensional (2D) infrared, and femtosecond stimulated Raman spectroscopy techniques with organometallic intermediates, organic excited states, and the dynamics of the tertiary structure of DNA. 相似文献
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P.-C. Harizanis E. Alissandrakis P.-A. Tarantilis M. Polissiou 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(10):1272-1277
Protection of honeycombs from the Wax moth, Galleria mellonella, involves the use of physical, biological or chemical control methods. As chemical control may result in residues in the extracted honey, the presence of p-dichlorobenzene and naphthalene residues was investigated by solid-phase microextraction (SPME) coupled to gas-chromatographic/mass spectrometry (GC/MS). The method was linear between 5 and 200 µg kg–1 honey for p-dichlorobenzene and 1 and 200 µg kg–1 for naphthalene. Limits of detection were 1 and 0.1 µg kg–1, respectively, for p-dichlorobenzene and naphthalene, while relative standard deviations were 2.6 and 7.9%, respectively. Application of the method to 90 unifloral Greek honeys revealed that, in 25.6% of the samples, the concentration of either one of the pesticides exceeded the maximum residue level (MRL). Maximum concentrations were 163.03 µg kg–1 honey for p-dichlorobenzene and 193.74 µg kg–1 honey for naphthalene. Naphthalene was found in traceable amounts in 78.9% of the samples, but only 5.6% of them contained concentrations above the MRL, which indicates the use of pre-contaminated honeycomb foundations or built combs. Nevertheless, because naphthalene is naturally present in some plant species growing in Greece, the contribution of nectar from such a floral source should not be overlooked. 相似文献
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Apostolos C. Tsolakis Ioannis Moschos Alexandros Zerzelidis Pantelis Tropios Stylianos Zikos Athanasios Tryferidis Stelios Krinidis Dimosthenis Ioannidis Dimitrios Tzovaras 《国际能源研究杂志》2019,43(6):2261-2280
In this paper, an intelligent occupancy‐based, automated building control system is initially introduced, which has the capability of reducing energy consumption while respecting the occupants' comfort and actions inside building areas. Data stemming from a multisensorial network is combined with implicitly extracted information, since no direct feedback is expected by the users, towards unsupervised monitoring and control of building operation. However, due to significantly higher costs of actuating equipment and the reluctance that some end users show in accepting fully automated solutions, a new hybrid approach is conceptualized and presented; the automated decision support system is supplemented with a persuasion mechanism aimed at increasing energy savings, through raising user awareness. The persuasive methodology employs a continuous feedback mechanism in order to select the optimal incentive strategy by taking into account user success rates, in terms of requested actions, as well as available mechanisms, and daily harassment. 相似文献
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E. Anastasaki C. Kanakis C. Pappas L. Maggi C. P. del Campo M. Carmona G. L. Alonso M. G. Polissiou 《European Food Research and Technology》2009,229(6):899-905
The volatile compounds of saffron of different origins were investigated to check their suitability as markers of geographic
differentiation. A total of 247 saffron samples from Greece (40 samples), Iran (84 samples), Italy (60 samples) and Spain
(63 samples) which were harvested in 2006 were analysed using ultrasound-assisted extraction, gas chromatography followed
by mass spectrometry and flame ionisation. All regions were easily differentiated by canonical discriminant analysis. The
percentages of correct classification and validation were 96.4 and 94.3%, respectively. These investigations showed the potential
of saffron volatiles to discriminate saffron samples with different geographical origins. 相似文献
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