Veränderungen des Gesamtglucosinolatgehaltes von Rapssaat während der Abreife nach Analysen mit Glucose-, HPLC-, H1-(Sulfatase-) und RFA-Methode

Changes in the Total Glucosinolate Content in Rapeseed during Maturation Analyzed by Glucose, HPLC, H-1 (Sulfatase) and X-RF Method The aim of the reported research work was the investigation and quantification of the development of the total glucosinolate content in rapeseed during maturation in order to give a contribution to explain the deviations of results from different analytical methods on identical samples. Results derived by X-RF and H-1 (sulfatase-) method were independent from the stage of maturation. However, the results of HPLC- and glucose release analyses showed continuously increasing values up to harvesting. The supposed reasons for this phenomenon are temporal modifications in the structure of the sidechain and glucose rest of the glucosinolate molecule. The reported results should be observed in intercomparisons of methods of glucosinolate analysis as well as in the certification of seeds and consum batches of oilseed rape. The fact that long before harvest the results derived by X-RF and H-1 method show a constant level offers the opportunity of a prognosis of the probable quality of certain seed batches by means of a pre-harvest analysis.     

Relations between Total Sulphur and Glucosinolate Content in Rapeseed – Calibration of the X-RF Method

The X-RF method according to Schnug and Haneklaus has become a widely used method for the determination of the total glucosinolate content in rapeseed. This contribution deals with the calibration of the method by means of the standard reference rapeseed materials supplied by the Commission of the European Communities and describes the upgrading of results derived by calibration systems formerly released for the X-RF method. In addition guidelines for the correction of data obtained from samples with extreme deviations in seed protein content and composition are described.     

Ergebnisse eines Ringversuches zur röntgenfluoreszenzanalytischen Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen

Results of a Ring Test with the X-Ray-Fluorescence-Method for the Determination of Total Glucosinolate Content in Rapeseed In order to quantify comparability and accuracy of the X-RF method for the determination of the total glucosinolate content in rapeseed a ring test was established with three laboratories and 24 seed samples in may 1987. The trial yielded the following results: the average value for the reproducibility (r) was 1.6 μmol/g, the average value for the comparability (R) was 4.0 μmol/g, the correlation between values derived from X-RF method and HPLC was 0.98; the standard deviation for accuracy 4.0 μmol/g; by a mathematical correction of the results from the X-RF method for a standard protein content of 22% the correlation coefficient increases to 0.992 and the standard deviation of accuracy decreases to 2.5 μmol/g.     

Preparation Techniques of Small Sample Sizes for Sulphur and Indirect Total Glucosinolate Analysis in Brassica Seeds by X-Ray Fluorescence Spectroscopy

Two new preparation techniques for Brassica seeds are introduced, which enable the determination of total sulphur concentrations and indirectly the total glucosinolate concentrations in small sample sizes and single seeds by means of X-ray fluorescence spectroscopy. Small sample sizes, down to 250 mg, are milled in peppermill type grinders and prepared as thin layers in liquid cuvettes. Single seeds are embedded by means of a sulphur free glue based on acetylated glucose in wax tablets and cut into halves. Measurement and calibration for small sample sizes are in accordance with the rules for the original X-RF method. In case of single seeds the area of the cut surface need to be estimated and the collected S-Kα intensities corrected for the active fluorescent area of the standard reference materials.     

Comparative study of different methods for the assessment of print nonuniformity and their correlation with the human visual system

Print nonuniformity is the variation of optical density (reflection) on the print and can occur in several different types that can be classified into two basic groups: random and systematic variations. This article examines two types from each group of variations that are most commonly found in digital printing systems: blotches and streaks, where amplitude and size were varied. Three most commonly used methods for measuring the print nonuniformity were used: Grey Level Co-occurrence Matrix (GLCM), ISO 13660 and Integration (also Improved Integration) method. The results obtained by measuring were compared with a visual assessment to find the link between objective and subjective analysis and to define and determine which method/parameter is the best for the measurement of which type of print (non)uniformity. The obtained results indicate the possibility of selecting the measurement parameter, but that the choice of the parameter depends on the type of nonuniformity. It is concluded that in the case of the GLCM method, the entropy and energy parameters are strongly related to the visual assessment for all three sets of samples. These parameters can be used regardless of the type of nonuniformity. The ISO G parameter can be used to measure both graininess and mottling, while the ISO M parameter is only suitable for measuring mottling. Integration method could be used to measure systematic error. On the basis of conclusions of the research, it is possible to propose the development of an industrially applicable solution for measuring print nonuniformity of digitally printed samples.     

Coagulation in a diffusing Gaussian aerosol puff: Comparison of analytical approximations with numerical solutions

In order to quantify the effective contribution of emission sources to background aerosols, it is necessary to model the transformation of particle size distributions during their dispersion in the atmosphere. To this end, we formulate a diffusion–coagulation model for the evolution of a spatially inhomogeneous aerosol puff and develop solutions under the assumption of an initially Gaussian distributed particle number concentration and spatially separable size spectra. The analytical solutions have been obtained for constant and free-molecular coagulation kernels by combining prescribed diffusion approximation, (originally due to Jaffe in ion recombination theory), with Laplace transforms and scaling theory, respectively. While, the formulae for the survival fractions obtained within the framework of Jaffe approximation have similar functional forms as those obtained by earlier investigators [Turco, R.P., Yu, F., (1997). Aerosol invariance in expanding coagulating plumes. Geophysical Research Letters, 24, 1223–1226] based on a uniformly mixed expansion model, the present approach provides definite prefactors involving the physical parameters of the processes. The results have been tested against numerical solutions developed by combining finite difference with nodal method as well as using differential equation solver package of Mathematica. Although the analytical results for the temporal variations of the survival fractions follow similar trends as numerical predictions, they show systematic deviations up to about 25% under strong coagulation. This suggests that the expansion-coagulation models are not fully equivalent to diffusive-coagulation models except in the limit of Jaffe approximation. The approximate formulae are useful for providing estimates of the required source modifier terms for predicting the particles injected as background aerosols into the atmosphere using the emission factors estimated at the source point. The results are further discussed.     

Schnelle und präzise Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen-Vergleich der Röntgenfluoreszenzanalyse mit Gaschromatographie und Hochdruckflüssigkeitschromatographie

Rapid and Precise Determination of Total Glucosinolate Content in Rapeseed – Comparison of X-Ray Fluorescence Spectroscopy with Gaschromatography and High-Performance-Liquid-Chromatography The introduction of oilseed-rape cultivars poor in glucosinolates within the EG requires methods which allow a separation of the yield batches by the glucosinolate content. By means of the indirect determination of the glucosinolate content by X-ray-spectroscopy a method is introduced that produces a high correlation with conventional procedures (r² = 99% for GC-reference samples, r² = 92% for GC single data, r² = 96% for HPLC single data; deviations from average values: GC-reference samples 1.3%; single analyses of GC and HPLC 7.4 respectively 3.1%) and that needs only 4 minutes for one complete determination and is easily to perform.     

The Quantitative Analysis of Glucosinolates in Cruciferous Vegetables,Oilseeds and Forage Crops Using High Performance Liquid Chromatography

An hplc method of glucosinolate analysis is described which allows the quantitative determination of these compounds in cruciferous oilseeds, vegetables and forage crops. The method compares favourably with a gas chromatographic technique for individual glucosinolate analysis and has several advantages which are particularly useful for the analysis of seed and leaf material. Whilst no attempt has been made to optimise the analytical procedures to allow the rapid screening of breeding programmes, this would not appear to be limiting.     

Analytical optimization and sensitivity analysis of forced periodic chemical processes

Intentional periodic manipulation of the inputs to a chemical reactor can in some cases improve the amount of product and its composition. A variational method for analyzing the effects of single and multivariable periodic forcing functions on process performance is presented in this work and illustrated in several examples. While the method discussed here is not theoretically justified for large-amplitude input variations, comparisons of analytical results obtained with the method and simulation results for large-amplitude reactor cycling show good qualitative agreement. The approximate analytical method provides a reasonable initial estimate of the structure of an advantageous periodic control.     

Mass transfer during osmotic dehydration of green bean in salt solution: A polynomial approximation approach

In this study, moisture and solute variations inside cylindrical green bean samples during osmotic dehydration in salt solution were predicted using a modified lumped mathematical model. The polynomial approximation approach was used to obtain the average moisture and solute concentrations in the radial direction. Results of the proposed model were compared with the experimental data, obtained from osmotic dehydration of long cylindrical samples of green bean in different temperatures and concentrations of salt solution, as well as the exact solution of the original partial differential equation. Results show that the P. A. method's predictions followed the general trend of the experimental dehydration curves. Also dehydration curves show a good agreement between the P. A. and exact analytical method's predictions. The values of mean relative errors between the P. A. method's predictions and experimental data are between 14 and 24%. Also the related mean relative errors for exact analytical method are between 10 and 27.5%. Although the exact analytical solution provides better results, as expected, but considering the approximate nature of the P. A. method and in view of the fact that the deviations of P. A. and the exact analytical methods from the experimental data are comparable, the P. A. method could be used because of its simplicity.     

Determination of free fatty acids in edible oils by 1H NMR spectroscopy

Here we describe a novel ¹H NMR assay for the determination of FFAs in edible oils. The analytical performance of the NMR assay is similar to that of the commonly used acid value (AV) method. A total of 120 edible oil samples were analysed by both approaches. Except for pumpkin seed oil, showing slight deviations, there was a good compliance between the results obtained from the two methods.     

Oil and protein analysis of whole rapeseed kernels by near infrared reflectance spectroscopy

Oil, protein, chlorophyll and glucosinolate content were analyzed in whole rapeseed kernels by use of a near infrared reflectance technique. Oil and protein content could be estimated with high correlation and good accuracy when predicted results for 89 samples were compared to standard laboratory results. For oil, a multiple correlation coefficient (R) of 0.954 and a standard error of estimate (Sy) value of 0.83 were obtained when reflectance was measured at eight wavelengths. For protein, R = 0.964 and Sy = 0.88 were obtained when reflectance was measured at six wavelengths. Significantly lower correlations were obtained for prediction of chlorophyll (R = 0.506) and glucosinolate (R = 0.707) content, and presently near infrared data cannot be used to measure these two constituents. For the prediction of oil and protein, the levels of accuracy obtained are sufficient for many analytical purposes, and if needed, the accuracy can be improved by repeated measurements. The method is rapid, involves no sample preparation, and leaves intact, viable seed available for other purposes. Contribution no. 468 of the Grain Research Laboratory. Presented in part at the 65th Annual Meeting of the American Association of Cereal Chemists, September 1980, Chicago.     

Methodische Untersuchungen zur Glucosinolatbestimmung bei Raps

Methodical Investigations of Glucosinolate Determination of Rape Seed The decrease of the glucosinolate content, due to cultivation, causes analytical problems, because the GSL sample is significantly altered in dependence on the total GSL content. Comparative analyses, obtained by isothermic gaschromatography and HPLC show that the share of the indolyl-glucosinolates can increase up to 30–40%, if the total GSL content is diminished to about 3%. Besides the mentioned methods of HPLC and GC photometric procedures were examined with respect to their suitability to determine the total GSL content in rape seed.     

A new generalized corresponding-states equation of state for the extension of the Lee-Kesler equation to fluids consisting of polar and larger nonpolar molecules

The Lee-Kesler equation of state for the thermodynamic properties of small nonpolar fluids is extended to all fluids consisting of polar and larger nonpolar molecules, based on the general corresponding-states theory for highly nonspherical fluids. The thermodynamic functions are represented by an analytical equation of state. The results for polar fluids are substantially better than those obtainable from other currently available methods, while the results for nonpolar fluids are equivalent to and mostly better than those obtained by the Lee-Kesler method. The input data required are the critical temperature, the critical volume, the acentric factor and the aspherical factor, which is related to the critical compression factor; the critical volume is therefore required in the present method. The method developed in this work shows good accuracy for 15 representative nonpolar, polar, hydrogen bonding and associating fluids and provides a simple method for industrial applications. Average deviations for the compressibility factor, the heat capacity and the speed of sound for six nonpolar and nine polar fluids from the new equation of state are 0.74%, 2.1% and 2.3%, which are about 8 times smaller than those obtained from the Lee-Kesler equation (about 5.6%, 17% and 29%, respectively).     

Investigation of the steady state measurement process

Based on the role of steady state concept in the model of analytical chemical measurement and deduction, the definition of ‘practically sleady slate’ (PSS) has been inlroduced. The defnition does not require the process to be in steady state in a strictly mathematical sense. In order to fulfil the requiremenls of ‘practically steady state’ the random error and the syslematic error must vary within a suitable limit, and the expected fgure for the measured value must be within a specified range.The goal of the present investigation was to detect the steady state of the measurement process with respect to the analytical information (peak area ratio) based on the measured values. The method proposed proved to be useful for the determination of the simultaneously present systematic error and random error. Control based on the measured values of the internal standard is useful, but additional information is necessary. There are several advantages to the method described: the results for the internal standard indicate possible sources of disturbances and allow the end of the steady state measurement process to be predicted.     

Improvement in hydrolytic procedure for GLC determination of non-indolyl glucosinolates in rapeseed as isothiocyanates

Some methods determine the non-indolyl glucosinolates content in rapeseed as their hydrolysates: the isothiocyanates and the oxazolidinethiones. These methods in their present form underestimate the amount of the glucosinolates content. In this investigation, a modified method was developed to give a better quantitative estimate, indicating a glucosinolate level five times that obtained by a typical existing method.     

<Superscript>1</Superscript>H-NMR Spectroscopy as a New Tool in the Assessment of the Oxidative State in Edible Oils

Within the course of lipid peroxidation, hydroperoxides are formed as primary products. They can be used as analytical markers to assess the deterioration status of oils and fats. Here a new ¹H-NMR assay to determine the hydroperoxide amount in edible oils is presented. We were able to show that the analytical performance of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler. A total of 290 edible oil samples were analyzed using both methods. For some oil varieties considerable discrepancies were found between the results obtained. In the case of black seed and olive oil, two substances could be identified that cause positive (black seed oil) and negative (olive oils) deviations from the theoretical PV expected from the NMR values.     

Nonlinear inferential control

Due to unmeasured distrubances and nonlinearities typical for chemical processes the performance of state reconstruction schemes based on linearized system is often unsatisfactory. Unmeasured disturbances yield biased state estimates because generally only proportional feedback is used in the estimators. Set point changes or large disturbances make linear estimators invalid for most chemical processes. Static and dynamic nonlinear estimation schemes are derived in this paper when persistent or slowly varying disturbances (nonstationary noise) affect the system. Because an analytical solution for general nonlinear systems is impossible, approximate methods are suggested to reduce the computational effort necessary for evaluating the estimate. The method is applied to two CSTR's in series where concentration estimates are obtained from temperature measurements. The results are significantly better than those obtained by linear estimation techniques. A convenient measurement selection criterion is also derived which aims at minimizing the sensitivity of the estimate to unmeasured disturbances.     

水泥及原料中游离氧化钙测定要点

水泥行业化学分析测定游离氧化钙的方式有很多种,GB 176—2017《水泥化学分析方法》中规定了甘油法、乙二醇法和乙二醇萃取-EDTA滴定法三种测定方法，各种检测方法的适用性不尽相同，本文通过对几种常用分析方法操作要点进行说明，分析三种测定方法的误差来源及注意事项，为不同材料中游离氧化钙测定方法的合理选择提供参考。