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为了进行红外光谱定量分析纤维含量的研究,测试了不同比例木棉/棉混合物的红外光谱图,探讨了红外光谱定量分析木棉/棉混纺比的方法。研究表明,1732cm-1和1242cm-1处特征吸收峰面积与木棉含量的线性关系明显,1732cm-1处最佳。以1732cm-1处的特征吸收峰面积对木棉/棉混纺试样的木棉含量作了定量分析,得出了线性关系较好的标准曲线。用本法对未知样品的木棉含量进行测定,得到了较好的结果。 相似文献
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研究了傅里叶红外光谱技术结合区间偏最小二乘法(iPLS)快速分析食用油中低含量(0.1%~5%)反式脂肪酸的分析方法。通过系统地比较衰减全反射红外光谱法(ATR-FTIF)及衰减透射红外光谱法(TR-FTIR)光谱的模型效果,优化建模区间。研究结果表明,ATR-FTIR、TR-FTIR-PLS回归模型均能有效测定油脂中低浓度反式脂肪酸的含量,但TR-FTIR法灵敏度优于ATR-FTIR法。iPLS区间选择结果显示,以1 000~940 cm~(-1)波段透射光谱建模,相关系数R~2为0.998 8,标准集的RMSEC 0.016 6,验证集RMSEP为0.008 75,预测相对标准偏差2.92%,预测值与实际值高度相关,Y_(预测)=1.00X_(实际)-0.003 44,R~2=0.998 7。12组外部验证试验相对标准偏差为4.80%,说明预测精确度较高、模型稳定性好,有潜力替代传统气相色谱法用于油脂中低含量反式脂肪酸快速定量测定。 相似文献
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观察不同原料配比对合成的枸橼酸苹果酸钙钙含量、钙溶解性及红外光谱影响.4种用不同原料配比合成枸橼酸苹果酸钙,分别按中国药典方法测定钙含量、钙溶解性,用红外光谱仪测定4000 cm-1~400 cm-1吸收峰波数和强度.结果:4种不同原料配比合成枸橼酸苹果酸钙钙溶解性100mL钙元素分别为160.2、123.4、124.7、122.7mg,红外光谱测定图谱出现的吸收峰波数基本一致,特征峰更接近苹果酸钙,但4组样品红外光谱特征峰在相同波数下,强度有所不同.结论:不同原料配比对合成的枸橼酸苹果酸钙钙溶解性影响较大. 相似文献
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对市售的几种低温氧漂活化剂四乙酰乙二胺(TAED)采用广角X-射线衍射、红外光谱、紫外吸收光谱进行结构表征,测定了高纯度粉状TAED产品的溶解度,并对不同织物进行了双氧水/TAED活化漂白试验。结果表明,高纯度TAED产品在红外光谱中的1706cm-1和1680cm-1处存在酰胺I(C=O)伸缩振动的强吸收峰,1270cm-1和1193cm-1处存在酰胺III(C—N)伸缩振动的强吸收峰。各种TAED产品的水溶液在紫外吸收光谱215nm处均存在强吸收峰,可利用其吸收强度与浓度的线性关系检测各产品的浓度。高纯粉状TAED产品的溶解度随温度升高而增加,在70℃时的溶解度为17g/L。TAED产品剂型对漂白效果无影响,采用双氧水/高纯TAED产品对不同织物进行漂白,均能获得满意的漂白效果,且高效节能。 相似文献
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近红外光谱法对茶叶中的咖啡碱含量的快速测定 总被引:3,自引:1,他引:2
以贵州省各地茶叶为研究对象,以近红外光谱分析技术快速检测茶叶中的咖啡碱含量为目的,将茶叶制成粉末进行光谱扫描并用化学法测定其咖啡碱含量,将偏最小二乘法与傅立叶变换近红外光谱法相结合,建立茶叶中咖啡碱含量的模型.通过多元散射校正(MSC)处理光谱,光谱范围选择4493.33cm-1~4354.48cm-1,5800.83cm-1~5696.69cm-1,主因子数为10,得到模型的内部交互验证相关系数(P)为0.991,交互验证均方差(RMSECV)为0.205;模型的预测值与化学测定值的相关系数为0.999,预测标准偏差(RMSEP)为0.242.通过稳定性试验得到的RSD都在0.30%以下.结果表明,模型的预测效果很好,具有较高的精密度和较好的稳定性,且方法简捷,能满足茶叶中咖啡碱的快速检测要求. 相似文献
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为快速测定小麦及其制品呕吐毒素(deoxynivalenol,DON)污染情况,搜集小麦、面粉及面粉制品共98?份,利用衰减全反射-傅里叶变换红外光谱(attenuated total reflectance-Fourier transform infrared spectroscopy,ATR-FTIR)获取样品在4 000~600 cm-1的光谱信息,对样品中的DON含量建立了基于偏最小二乘回归(partial least squares regression,PLSR)分析和逐步多元性回归(stepwise multiple linear regression,SMLR)分析方法的定量分析模型。结果显示,不同DON含量样品在1?740、1?648、1?549?cm-1和1?300~900?cm-1等波段处的吸收值存在显著差异。PLSR和SMLR均能较好预测样品中的DON含量,其中PLSR模型的预测集决定系数RP2、预测均方根误差(root mean squared error of prediction,RMSEP)和相对分析偏差(residual predictive deviation,RPD)值分别为0.86、0.438?mg/kg和2.6。SMLR结合9?个波长所建模型的RP2、RMSEP和RPD值分别为0.86、0.426?mg/kg和2.6。结果表明,ATR-FTIR用于小麦及其制品DON污染快速分析具有可行性。 相似文献
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Abdul Rohman Anjar Windarsih Sugeng Riyanto Sudjadi Shahrel Ahmad Shuhel Ahmad Arieff Salleh Rosman 《International Journal of Food Properties》2016,19(3):680-687
Avocado oil is one of the functional oils having high quality and high price in the market. This oil shows many benefits for the human health and is applied in many cosmetic products. The authentication of avocado oil becomes very important due to the possible adulteration of avocado oil with other lower priced oils, such as palm oil and canola oil. In this study, Fourier transform infrared spectroscopy using attenuated total reflectance in combination with chemometrics techniques of partial least squares and principal component regression is implemented to construct the quantification and classification models of palm oil and canola oil in avocado oil. Partial least squares at the wavenumbers region of 1260–900 cm–1 revealed the best calibration models, having the highest coefficient of determination (R2 = 0.999) and the lowest root mean square error of calibration, 0.80%, and comparatively low root mean square error of prediction, 0.79%, for analysis of avocado oil in the mixture with palm oil. Meanwhile, the highest R2, root mean square error of calibration, and root mean square error of prediction values obtained for avocado oil in the mixture with canola oil at frequency region of 3025–2850 and 1260–900 cm–1 were 0.9995, 0.83, and 0.64%, respectively. 相似文献
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Attenuated total reflectance Fourier transform infrared spectrometric method for determination of crocin in commercial saffron samples was studied. Calibration models were built based on the peaks at spectral region of 1700–900 cm?1 and spectral wavenumbers with correlation coefficient (r) greater than 0.99 were selected for quantification of crocin in the samples. The quantitative analysis of samples by attenuated total reflectance Fourier transform infrared was tested against reference UV-visible spectrophotometry method. Considerable correlation (r = 0.95) between both methods in prediction of crocin content among the saffron samples indicated that the proposed methodology has the potential application as a rapid screening tool. 相似文献
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Fourier transform infrared spectrometer equipped with attenuated total reflection and chemometrics were used to determine added sugar content (ASC), total soluble solids (TSS) and real juice content (RJC) in fresh and commercial mango juice. Sucrose solutions (0-27%), fresh mango juice adulterated with 0-27% sucrose, and two commercial brands were evaluated in wavenumber range of 4000-650 cm−1. Partial least squares (PLS) discrimination and principal component analysis (PCA) were used to classify the samples with or without ASC. PLS and multiple linear regression (MLR) were carried out with and without data treatments. The detection limit for ASC was 3% for samples with low natural TSS, 5% for samples with natural TSS more than 10% and 3.6% for commercial samples. ASC, TSS, and RJC were predicted in the wavenumber range of 1476-912 cm−1 using PLS (multiple correlation coefficient, R = 0.99) and three wavenumbers (1088, 1050, 991 cm−1) using MLR (R = 0.98). 相似文献
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联合使用连续小波变换(continuous wavelet transform,CWT)和广义回归神经网络(generalized regression neural networks,GRNN)建立用于测定樱桃中糖含量的CWT-GRNN 预测校正模型。利用CWT 提取樱桃样本数据中反映含糖量的关键光谱特征,在CWT 域中选择3 个具有代表性的尺度,并在每个尺度下根据樱桃样本的可见- 近红外光谱的特征将其划分为4 个特征区间,从而构造12 个特征输入到GRNN,GRNN 的光滑因子取为0.0001。CWTGRNN模型对20 个预测样本集中的樱桃含糖量的预测相对误差在2% 以内。结果表明,可见- 近红外光谱技术可以快速、准确和无损地测定樱桃中的含糖量,本研究提出的方法可以用于果蔬产业的品质管理与控制。 相似文献
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André Machado Rech Fábio Henrique Weiler Marco Flôres Ferrão 《Food Analytical Methods》2018,11(7):1986-1993
Partial least square (PLS) regression models were developed and compared in order to determine the total sugar content in soy-based drinks using an infrared spectroscopy technique known as attenuated total reflectance Fourier transform infrared (ATR-FTIR). On a spectrophotometer set for analyzing on the middle infrared region, spectral band of 1900 to 900 cm?1, commercial samples of soy beverage were analyzed, as well as samples with crescent water additions of 5, 10, and 20% v/v. Reference data for total sugars were obtained using the Lane-Eynon method. To construct regression models, algorithms of interval partial least square (iPLS) and synergy of interval partial least square (siPLS) were applied using iToolbox package on Matlab 8.1 environment. Kennard-Stone algorithm was used to the selection of calibration and prediction sets. Two models have been the best obtained: the first was an iPLS with seven latent variables, which selected the spectral band of 1399–900 cm?1 and presented root mean square error of cross-validation (RMSECV)?=?0.1678% (w/w). The second best model was siPLS with six latent variables, which selected spectral bands of 1025–1150 and 1151–1476 cm?1 and presented RMSECV?=?0.1963% (w/w). The proposed method presents advantages such as a small-required amount of sample for spectrum achievement, no sample destruction, and a high analytical frequency. 相似文献
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Mid-infrared spectroscopy as a tool for rapid determination of internal quality parameters in tomato 总被引:2,自引:0,他引:2
Iwona Ścibisz Maryse Reich Sylvie Bureau Barbara Gouble Mathilde Causse Dominique Bertrand Catherine M.G.C. Renard 《Food chemistry》2011
The objective of this study was to investigate the possibility of predicting the quality parameters of tomato by mid-infrared spectroscopy. For 2 years, tomato samples, representing a large variability in the chemical composition, were scanned using the attenuated total reflectance accessory of a Fourier transform spectrometer in the wavenumber region between 4000 and 400 cm−1. Calibration models were developed using partial least squares (PLS) regression method and were tested with internal validation sample set in the first year. Different spectral preprocessing techniques were investigated and different spectral regions were selected to optimise the calibration models. In addition, the models obtained in 2007 were used to predict the soluble solids, dry matter and total acidity in tomato harvested in 2008. 相似文献
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The identification of foodborne microorganisms and their endospores in food products are important for food safety. The present work compares Bacillus (Bacillus licheniformis, Bacillus circulans and Bacillus subtilis) and Micrococcus (Micrococcus luteus) species with Fourier transform infrared (FTIR) spectroscopy. Our results show that there are several characteristic peaks belonging to both the Micrococcus and Bacillus species which can be used for the identification of these foodborne bacteria and their endospores. For Micrococcus species, a new band was observed at 1338 cm−1 which may be due to acetate oxidation via the carboxylic acid cycle. The bands at 1313 cm−1 and 1256 cm−1 can be explained by an exopolymer formation and the other bands at 1074 cm−1 and 550 cm−1, may be due to the glycogen-like storage material in Micrococcus spp. There are also characteristic peaks at 993 cm−1 and 801 cm−1 for these bacterial species. Different Bacillus species also showed characteristic peaks at 1000–500 cm−1 region. Dipicolinic acid (DPA) bands at ∼728 cm−1 and ∼703 cm−1 seen only in B. circulans were the marker of an endospore formation. 相似文献
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Xiaoping Hu Kiyohiko Toyoda Minoru Yamanoue Ikko Ihara Kaori Nakai 《Food and Bioprocess Technology》2010,3(6):883-891
Japanese black Wagyu beef has its characteristics of fatty well-marbled texture, flavor, and tenderness which are affected
by fatty acid composition. The aim of this study was to develop an analytical method for evaluating the fatty acid profile
of Wagyu beef by Fourier transform infrared (FTIR) spectroscopy. In the current study, attenuated total reflection–FTIR (ATR-FTIR)
spectroscopy and gas chromatography (GC) were applied to the fat tissues, and the solvent-extracted fats which were sampled
from subcutaneous, inter- and intramuscular fat tissues. Results of GC analysis showed that monounsaturated fatty acids (MUFA)
content became larger in the order of intramuscular, intermuscular, and subcutaneous fats, and saturated fatty acids (SFA)
became smaller in the same order. Subcutaneous fat could be discriminated from inter- and intramuscular fats on the basis
of fatty acid composition by principal component analysis. The ATR-FTIR analysis revealed that the shift of the peak positions
of alkene C–H stretching vibration at around 3,006 cm−1 occurred depending on the unsaturation degree of fatty acids in beef fat. Partial least squares (PLS) regression analysis
with leave-one-out cross-validation was applied to the combined regions of 2,800–3,050 and 1,000–1,500 cm−1 for the fat tissues and the extracted fats. The correlation coefficients of the PLS validation models predicting the content
of the MUFA and SFA for solvent-extracted fats were higher than those for fat tissues, and the coefficients (R
2) of determination more than 0.873 were obtained for solvent-extracted fats and 0.522 for fat tissues. 相似文献
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The possibility of using the whole spectra (wave numbers between 4000 and 850 cm−1) from Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) to differentiate between good, marginal and unacceptable oils with regard to various intensities of oil rancidity was investigated. Fresh, used, and discarded oils were collected from several fast food restaurants from each frying cycle for 4 weeks. Dielectric constant, peroxide value, free fatty acid content, and density of oil samples significantly (P<0.01) increased with frying time. The correlation (r) between FTIR absorbance at 3300 cm−1 and free fatty acid content was from 0.84 to 0.94 for oils from the three restaurants. Similarly, the correlation between FTIR absorbance at 3471 cm−1 and peroxide value was from 0.90 to 0.97. The results of principal component analysis using the whole spectra (4000-850 cm−1) showed good discrimination and stability for identification between acceptable, marginal and unacceptable frying oils. 相似文献