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1.
熊艳梅  唐果  段佳  李春子  闵顺耕 《分析化学》2012,40(9):1434-1438
利用近红外、中红外和拉曼光谱法定量分析了商品农药制剂中有效成分氰戊菊酯和马拉硫磷的含量.采用偏最小二乘法(Partial least squares,PLS)建立氰戊菊酯和马拉硫磷的定量模型并进行了优化,用独立检验集对模型适应性进行评价.近红外和中红外法测定氰戊菊酯、马拉硫磷定量模型的相关系数分别是0.9981,0.9994和0.9946,0.9998,外部验证集标准差分别是0.082,0081和0.092,0.075,两种方法的定量效果接近;拉曼法氰戊菊酯和马拉硫磷定量模型的相关系数分别为0.9872和0.9993,外部验证集标准差分别为0.254和0.317,预测精度不及近红外和中红外法高.MIR-ATR,NIR和Raman 3种方法均能满足现场检测农药质量的需要.  相似文献   

2.
《Analytical letters》2012,45(15):2380-2390
The development of a simple and cost-effective method for the determination of the release of coated urea has significant implications. Fourier-transform infrared spectroscopy with attenuated total reflectance was employed to determine the release of urea through univariate and multivariate calibration. The results indicated that univariate calibration did not accurately predict the release of urea, whereas partial least squares based on multivariate calibration performed significantly better. Partial least squares had the highest accuracy when the band located at 1420–1520 per centimeter was employed as the input. Moreover, the accuracy was further improved when segmented partial least squares models were developed at low and high urea concentrations. Unsegmented and segmented partial least squares models were employed, and release values were comparable to those measured by colorimetry. This work demonstrated the use of infrared spectroscopy and partial least squares to characterize the release of coated urea.  相似文献   

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4.
The aim of this study is to evaluate the biochemical changes in the leaves of wheat seedlings exposed to gold nanoparticles (AuNPs) nondestructively and rapidly using attenuated total reflectance Fourier transform infrared spectroscopy and laser-induced fluorescence. The 18?nm size gold nanoparticles are synthesized by citrate reduction. For analyzing the effect of gold nanoparticles on wheat seedlings, the treatment of gold nanoparticles was applied to the seedlings through roots and following the spectroscopic measurement of biochemical signatures. The laser-induced fluorescence measurement has been performed to access the effect of gold nanoparticles on the chlorophyll concentration of wheat seedlings. The decrease in the fluorescence intensity and the fluorescence intensity ratio on the treatment of gold nanoparticles indicates increase in the concentration of chlorophyll in the leaves of wheat seedlings. The attenuated total reflectance Fourier transform infrarred spectroscopy in combination with principal component analysis has been used to visualize the biochemical changes in the cellulose, hemicellulose, pectin, lignin, amino acids, proteins, and lipid of the leaves of wheat seedlings by recording infrared spectra in the region from 4000 to 400?cm?1. Principal component analysis applied to the preprocessed infrared data clearly distinguishes the spectral variability between control and gold nanoparticle treated seedlings. The study shows that exposure of gold nanoparticles increases the concentrations of cellulose, hemicelluloses, pectin, and lignin in the leaves of wheat seedlings. The increase in these chemicals indicates the modulation of cell walls of the wheat seedlings by the gold nanoparticle treatment. The exposure to gold nanoparticles also enhances the expression of lipid and proteins in the leaves of wheat seedlings.  相似文献   

5.
《Analytical letters》2012,45(1):167-177
Attenuated total reflectance Fourier transform infrared spectroscopy was used to detect DNA hybridization on a polystyrene conjugated gold nanoparticle thin film. The gold nanoparticles were synthesized on the surface of poly(ethylenimine) coated polystyrene particles by citrate reduction. Single-stranded DNA was then immobilized on the nanoparticle surface via thiol bonding. Ultraviolet-visible spectrometry was used to monitor the conjugation of the nanoparticles on polystyrene particles and the immobilization of a single-stranded DNA probe. The morphology of the polystyrene-gold nanoparticle thin film was characterized using scanning electron microscopy and showed successful conjugation and immobilization. The infrared spectra obtained from the hybridization showed features of DNA structure and peak shifts at 1657 cm?1 compared to the non-complementary DNA due to changes in hydrogen bonding between N-H and C?O of complimentary bases pairs. The peaks at 1067, 975, 920, and 859 cm?1, which were shifted to lower wavenumbers in the polystyrene-gold nanoparticle probe and target DNA, indicated hydrogen bonding formation between N-H and N of complimentary base pairs. ATR-FTIR spectroscopy provided simple, fast, and portable label-free detection of target DNA sequence on the polystyrene-gold nanoparticle thin film.  相似文献   

6.
《Analytical letters》2012,45(4):616-626
Infrared spectroscopy with attenuated total reflectance was investigated for the rapid determination of atractylenolide I and atractylenolide III contained in crude and processed Atractylodes macrocephala. High performance liquid chromatography was used as a reference method for the analysis, and a multivariate calibration model based on a partial least squares algorithm was developed to correlate the spectra and values determined by the reference method. The results suggested that the relative deviation of the predicted contents of atractylenolide I and atractylenolide III in the samples were less than 5.0%, which proved the stability and reliability of the models used. The proposed method is fast and nondestructive, and provides a novel, efficient, and environmentally-friendly approach for the rapid determination of the active components in crude and processed traditional Chinese herbal medicines.  相似文献   

7.
傅里叶变换红外光谱定量分析法测定盐酸雷尼替丁含量   总被引:5,自引:0,他引:5  
程存归  王飞 《分析化学》2003,31(10):1278-1278
1 引  言盐酸雷尼替丁片剂的商品名为兰百幸 ,又名呋喃硝胺、甲硝呋胍及胃安太 ,其化学名为N′ 甲基 N [2 [[[5 [(二甲氨基 )甲基 ] 2 呋喃基 ] 甲基 ]硫代 ]乙基 ] 2 硝基 1,1 乙烯二胺盐酸盐。它是一种选择性的H2 受体拮抗剂 ,能有效地抑制组胺、五肽胃泌素及食物刺激后引起的胃酸分泌 ,降低胃酸和胃酶活性。对胃及十二指肠溃疡的疗效高 ,具有速效和长效的特点。常见的盐酸雷尼替丁片剂中盐酸雷尼替丁含量的测定方法一般采用加水溶解后再用分光光度计测定 ,也有报道采用电极法进行含量测定。以往由于仪器的限制 ,红外光谱基本上…  相似文献   

8.
Sweta Sharma 《Analytical letters》2019,52(10):1629-1652
Widespread commercial application of titanium dioxide nanoparticles leads to their dispersion in the environment and inevitable interaction with living organisms. Their presence necessitates the monitoring of nanoparticle interactions with plants using advanced techniques that are capable of noninvasively and sensitively estimating the changes involved in the biochemical profile. The current study aims to investigate the effects of titanium dioxide nanoparticles on biochemicals of wheat leaves using label free, nondestructive, rapid, sensitive, and advanced spectroscopic probes: laser induced fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy coupled with multivariate analysis. The fluorescence and infrared spectra of control and titanium dioxide nanoparticle treated wheat leaves were acquired in the region from 400 to 800?nm and 4000 to 485?cm?1. The treatment of titanium dioxide nanoparticles decreases the chlorophyll content and the concentrations of cellulose, hemicellulose, xyloglucans, pectin, and lignin indicating interferences in the biosynthesis and structure of cell walls of the wheat leaves. The level of amide I, carbonyl, and methylene groups also increases following the treatment of titanium dioxide nanoparticles indicating lipid and protein peroxidation and the accumulation of carbonyl compounds. The changes in the integrated area ratios of the amide II/amide I, carbonyl/methyl, and methylene/amide II bands demonstrate disorder in the membrane integrity. This study establishes the efficiency of noninvasive, label-free, and rapid protocols based on attenuated total reflectance Fourier transform infrared and laser induced fluorescence to monitor the interactions of nanoparticles with plants at early stage of plant growth before visual signs of toxicity appear.  相似文献   

9.
运用全反射红外技术对逐层组装的含重氮高分子薄膜进行了分步定量分析.利用-CH2-峰的逐层变化规律,确认了在组装过程中每层吸附高分子的量是一致的.通过重氮基-N≡N+特征的吸收峰,定量计算了在特定实验条件下,-N≡N+分解生成共价键的比例.这些结果为认识重氮高分子薄膜的生长提供了更为直接和细致的信息.  相似文献   

10.
《Analytical letters》2012,45(1):111-123
ABSTRACT

Although diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is mainly used for powdered solid samples, it was found to be highly effective for the analysis of certain gemstones. Small amounts of oils and resins used to fill cracks and fissures in substandard (included) emeralds and rubies could be detected. Because of their very low levels, these organic adulterants can be difficult to detect by measurement of the infrared transmittance spectrum. Rubies have a significantly larger “window-of-detection” for organic clarifying agents than do emeralds. In some cases the spectral information was sufficient to identify the oil or polymer resin. Emeralds that were treated over 20 years ago are still easily identified. The position of the emerald or ruby in the sample holder can affect the intensity of C-H and O-H stretching frequencies as well as those brands characteristic to the gemstones.  相似文献   

11.
A method for measuring diffusion using a simple ATR device is demonstrated using water swollen cellophane film. The diffusion coefficient (D=0.56×10–9 m2 s–1) was comparable to previously published results for similar samples, but significantly different from recent measurements by NMR imaging on identical samples. An explanation is proposed based on cellophane morphology and diffusion through pores.  相似文献   

12.
The goal of the current study is to characterize the changes in the biochemical composition of the leaves of wheat seedlings stressed by arsenic at concentrations of 0.2, 0.3, 0.4, and 0.5?mM using laser induced chlorophyll fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy. The chlorophyll fluorescence spectra of the leaves of control and arsenic treated wheat seedlings showed increase in the intensity and intensity ratios of chlorophyll fluorescence bands indicating decrease in the photosynthesis performance and chlorophyll content of the leaves of wheat seedlings treated with arsenic. The infrared spectra of the leaves of control and arsenic treated wheat seedlings were obtained from 4000 to 485?cm?1 at a resolution of 4?cm?1. Multivariate principle component analysis of the preprocessed spectra suggest significant biochemical discrimination between the control and arsenic treated seedlings. Arsenic treatment decreased the concentration of cellulose while increasing the pectin, hemicellulose, xyloglucan, and lignin levels in the wheat seedling leaves. The exposure to arsenic also increased the spectral signatures of α-helix, β-sheet, amino acids, glutathione, lipids, and carboxyl compounds. These changes in the biochemicals indicate their physiological roles in mediating arsenic stress in wheat seedlings. The study also demonstrates the applicability of spectroscopic techniques for the non-invasive and rapid monitoring of the metabolism and physiology of the vegetation stressed by metals and metalloids before visual signs of toxicity appear.  相似文献   

13.
A simple and convenient assay based on single-drop microextraction with infrared spectroscopy is reported for the determination of selenium. The extraction conditions were carefully optimized and selenium was preconcentrated through single-drop microextraction in 1,2-dichloroethane containing N-hydroxy-N-phenyl-N′-(o-tolyl) benzimidamide. The method is selective and almost all common ions including molybdenum(VI), chromium(VI), and tungsten(VI) did not interfere with the isolation protocol. The selenite band at 875?±?2?cm?1, which is assigned to the asymmetric vibrational stretch (υ3), was used for the quantification of selenium. Low limits of detection and quantification of 2.0 and 6.6?µg?L?1 demonstrate the sensitivity of the method. Good precision was evaluated by the standard deviation (2.0?µg?L?1) and relative standard deviation (0.5%) for 8?µg?L?1 was achieved for 10 measurements. The method was used to analyze human blood, urine, and water for selenium.  相似文献   

14.
以完整油菜籽为样品,采用旋转杯和安培瓶两种样品杯、每种样品分为4×2种不同样品量并通过不同光谱预处理来优化油菜籽芥酸和含油量的近红外分析模型。结果表明:油菜籽各小样品含油量模型的决定系数(R2)从93.93%到96.93%不等,均方差(RMSECV)从0.56到0.79不等;油菜籽各小样品芥酸模型的决定系数(R2)从96.91%到98.42%不等,均方差(RMSECV)从1.73到2.43不等。随着样品量的逐渐增加,油菜籽芥酸和含油量不同样品杯模型各参数逐渐有所优化;同一样品厚度时,油菜小样品芥酸和含油量的旋转样品杯模型各参数均略优于安培瓶样品模型;不同样品量的NIRS模型,W3和W4差异不大,依次优于W2和W1。最小样品量AW1为0.3g。优化油菜小样品模型时,应该选择全部的预处理方法,根据优化结果选择最佳模型。外部检验结果表明:不同重量小样品(W1/0.3g、W2/1.0g、W3/2.0g和W4/4.0g)模型之间及其与标准化学值之间在0.01水平上差异不显著,说明W1和W2小样品模型同样可应用于油菜品质育种材料的分析选择。  相似文献   

15.
16.
谢志刚  黎司 《化学学报》2011,69(23):2896-2900
运用ATR-FTIR深入探讨了乐果和氧化乐果分子结构的特征振动及其酸、碱条件下水解历程对其特征结构振动的变化规律. 由实验结果, ATR-FTIR能够显著地区分乐果和氧化乐果两分子的结构振动. 氧化乐果在3302 cm-1 νas (NH), 3089 cm-1νas (CH2), 1739 cm-1 ν (C-O), 1554 cm-1 ν (O=C-N) II等峰位明显区别于乐果分子对应结构的振动峰位及其峰位强度. 碱性水解条件下, 乐果的ATR-FTIR特征表现在2108 cm-1平宽峰增强, 氧化乐果则表现为ν (P=O)红移和νas (P-O-C)蓝移|酸性水解条件下, 乐果ATR-FTIR中高波段的NH, CH3振动较强, 氧化乐果则因其分子链被破坏, 表现出无特征振动. 以上ATR-FTIR获得的结果从另一角度, 互补性地揭示了乐果和氧化乐果两分子内部的结构振动差别和酸、碱水解历程对其振动结构的影响变化. 为便捷、高效地区分物质分子结构的差异, 尤其是分子结构极为相似的细微结构的差异提供了较为完整的信息, 同时也为研究物质结构及其形态变化提供了十分有益的参考.  相似文献   

17.
Diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and headspace analysis gas-phase infrared spectroscopy (HAGIS) were used to investigate interactions between soils and the gasoline additive methylcyclopentadienylmanganese tricarbonyl (MMT). Various soil samples, as well as alumina and silica substrates, were studied. Each substrate exhibited a splitting or broadening of the degenerate e ν(CO) band of MMT, suggesting an interaction involving one or two of the CO ligands. The adsorption was shown to be reversible under relatively mild conditions using HAGIS. The proposed interaction is of the Brønsted type, involving the carbonyl oxygen and a surface-bound water or hydroxyl group. This type of interaction could stabilize MMT by inhibiting photo-ejection of CO ligands, a common first step in the decomposition of organometallic carbonyl compounds such as MMT. © 1998 John Wiley & Sons, Ltd.  相似文献   

18.
利用高效液相色谱(HPLC)法测定高粱籽粒中阿魏酸、原儿茶醛和花青素的含量,比色法测定总酚、总黄酮、缩合单宁的含量;运用偏最小二乘法建立NIR光谱与HPLC法和比色法分析值之间的多元校正模型,预测高粱籽粒中主要酚类物质的含量.结果表明,各成分近红外预测值与实测值之间的校正模型相关系数(R)、内部交叉验证均方差(RMSECV)、最佳主因子数分别为:总酚0.9737, 0.288, 4;总黄酮0.9660, 0.00671, 8;缩合单宁0.9558, 0.0289, 6;阿魏酸0.9818, 0.0391, 6;原儿茶醛0.9979, 0.0118, 5;花青素0.9977, 0.0523, 4;预测相对偏差(RSEP)分别为:总酚6.99%、总黄酮4.54%、 缩合单宁7.13%、阿魏酸2.68%、原儿茶醛5.46%、 花青素5.81%.结果表明,模型对样品NIR的预测值与其相应的化学值有较好的相关性,此模型可用来预测高粱籽粒中的各酚类物质的含量,在高粱优质育种和品质分析中具有广泛的应用价值.  相似文献   

19.
Black soldier fly (Hermetia illucens, L.) larvae are characterized by their ability to convert a variety of organic matter from food waste into a sustainable source of food (e.g., protein). This study aimed to evaluate the use of attenuated total reflectance (ATR) mid-infrared (MIR) spectroscopy to monitor changes in the composition as well as to classify black soldier fly larvae (BSFL) samples collected from two growth stages (fifth and sixth instar) and two waste stream diets (bread and vegetables, soy waste). The BSFL samples were fed on either a soy or bread-vegetable mix waste in a control environment (temperature 25 °C, and humidity 70%). The frass and BSFL samples harvested as fifth and sixth instar samples were analyzed using an ATR-MIR instrument where frequencies at specific wavenumbers were compared and evaluated using different chemometric techniques. The PLS regression models yield a coefficient of determination in cross-validation (R2) > 0.80 for the prediction of the type of waste used as diet. The results of this study also indicated that the ratio between the absorbances corresponding to the amide group (1635 cm−1) and lipids (2921 + 2849 cm−1) region was higher in diets containing a high proportion of carbohydrates (e.g., bread-vegetable mix) compared with the soy waste diet. This study demonstrated the ability of MIR spectroscopy to classify BSFL instar samples according to the type of waste stream used as a diet. Overall, ATR-MIR spectroscopy has shown potential to be used as tool to evaluate and monitor the development and growth of BSFL. The utilization of MIR spectroscopy will allow for the development of traceability systems for BSFL. These tools will aid in risk evaluation and the identification of hazards associated with the process, thereby assisting in improving the safety and quality of BSFL intended to be used by the animal feed industry.  相似文献   

20.
《Analytical letters》2012,45(11):1938-1951
This study employed near-infrared (NIR) spectroscopy to analyze content uniformity, moisture content, compression force, tablet hardness, average particle size, and particle-size distribution. The content uniformity, moisture content, compression force, tablet hardness, and average particle size models yielded high correlation coefficients (R2) of 0.99582, 0.99725, 0.99620, 0.96294, and 0.98421, respectively, whereas the particle size distribution models showed good predictive ability. Conventional criteria such as R2, root-mean-square error of calibration, and the root-mean-square error of prediction were used to evaluate the accuracy and precision of the model. To ensure the accuracy and predictability of the content model for low-dose tablets, additional validation and reliability evaluations were performed using 70%, 80%, 100%, 120%, and 130% drug concentrations as well as 90% and 110% active content formulations. Near-infrared spectroscopy with multivariate modeling is a rapid, nondestructive technique for the characterization of the manufacturing process.  相似文献   

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