酿造酱油中氨基氮含量测定的新方法

讨论了用两点电位滴定法测定酱油中氨基氮含量的新方法 ,本法只需在滴定终点前附近记录两次NaOH标准溶液体积和相应的 pH值 ,利用两点法公式计算滴定终点 ,从而确定氨基氮含量 ,并对方法的可行性及准确度做了分析。     

两点电位滴定法测定食盐中碘含量的研究

提出了用两点电位滴定法测定食盐中碘的新方法,该法只需在终点附近记录两次滴定数据即可计算滴定的化学计量点。实验结果表明:该法操作方便,数据处理简单,精密度与准确度均较高,分析速度较国标法有较大提高。     

蒸馏法测定葡萄酒中二氧化硫的不确定度分析

对蒸馏法测定葡萄酒中二氧化硫的不确定度进行了评定.通过对实验中不确定度各分量的分析计算,测得葡萄酒中二氧化硫的含量为(0.0929±0.0028) g/L(k=2).本实验不确定度具体由碘标准滴定溶液的标定及肉眼判断滴定终点所引起.     

伏特加碱度测定的不确定度分析

采用滴定法对于伏特加的碱度进行试验分析。以盐酸为滴定剂,以甲基红为指示剂,通过盐酸标准滴定溶液消耗量去计算试样的碱度。通过数学模型的建立,对于试验中的各个影响因素进行了分析评定,主要分析了容量瓶的容量允差、标准滴定溶液浓度、滴定操作过程以及重复性测定4个要素对于试验结果不确定度的贡献,其中贡献最大的两个要素为容量瓶的容量允差和滴定操作过程。通过针对各个不确定度的分量进行量化计算和合成,得出此试验用的伏特加碱度的不确定度表示为:2.0mL±0.054 mL。     

滴定液扩展不确定度的评定

目的建立滴定液标定浓度不确定度的评定方法。方法通过不确定度来源分析,建立滴定液不确定度的数学模型,从A类不确定度和B类合成不确定度两个方面进行评定,并对各不确定度的分量进行评估和计算公式的确认。结果计算各变量的不确定度,由此计算合成不确定度,最终得到测定结果的扩展不确定度和置信水平。结论对滴定液的各个不确定度的分量进行分析,确定各个分量的计算公式,为滴定液的标定不确定度提供一种具体、准确的评估方法;减小滴定液引起的误差,使实验获得更准确的结果。     

关于标准方法测定烟草还原糖时滴定度计量关系的讨论

在用标准方法测定烟草还原糖时,从KMnO_4标准溶液的标定,到试液中含Cu量的计算,其中各组分与以O_2计算KMnO_4滴定度的关系较为复杂,本文试图从理论上进一步阐述各组分之间的计量关系和滴定度的计算方法,以供初学者参考.     

造纸分析化验知识答疑——关于氧化还原滴定

滴定分析法因其操作简便、分析速度快而广泛用于造纸分析中。酸碱滴定法和氧化还原滴定法是造纸分析中使用得最多的两类滴定方法,但两种滴定方法因其分析机理不同在滴定操作中有较大差别。在造纸分析化验工作中,一些同志由于不了解氧化还原滴定法的特点,采用酸碱滴定法的操作去处理氧化还原滴定,因而在实际工作中产生了较多的疑难和困惑,使测定结果产生较大偏差。本文以问答的形式对造纸分析中常见的氧化还原滴定问题给予解答。     

高职化学基础课程思政教育实现路径探析

<正>化学基础是辽宁现代服务职业技术学院食品检验检测技术专业开设的一门专业基础课，主要研究物质的组成、含量、结构和形态等化学信息。通过学习这门课程，学生能够准确、全面地掌握化学的基本原理及数据的计算和处理，准确完成四大滴定分析（酸碱滴定、氧化还原滴定、沉淀滴定和配位滴定）实验操作，初步具备分析和解决食品检验检测中基本问题的能力，为后续食品分析、仪器分析等课程的学习及以后的工作打下必要的基础。化学基础课程自身含有丰富的思政元素，将专业实践技能和思政教育有机融合到一起，能够有效发挥化学基础课程的全方位育人功能。     

滴定法测定食醋中总酸含量及其不确定度评定

目的:建立酸碱中和滴定法测定食醋中总酸含量的方法,并对测量结果进行不确定度评定。方法:采用酸碱中和滴定法,以NaOH为滴定液,酚酞为指示剂,进行酸碱中和滴定,计算实验过程中各因素引入的不确定度,建立食醋总酸含量测定不确定度评定方法。结果:食醋总酸含量测定的不确定度为0.243%。结论:建立的不确定度评定法适用于氢氧化钠滴定食醋总酸含量的不确定度分析。     

硫酸标准滴定溶液浓度平均值不确定度的评定

化学试剂标准滴定溶液的配制和标定是粮食质量检验中最基本的操作之一,标准滴定溶液浓度的准确与否直接关系到检验结果的精准性。为保证检验结果的准确性,依据GB/T601—2002《化学试剂标准滴定溶液的制备》附录B《标准滴定溶液浓度平均值不确定度的计算》及《化学分析中不确定度的评估指南》,结合实际工作经验,对硫酸标准溶液0.1 mol/L的不确定度进行评定。     

醋酸杆菌合成细菌纤维素的发酵动力学研究

对巴氏醋酸杆菌合成细菌纤维素的发酵动力学特性进行了研究，通过Logistic方程，提出了发酵过程中菌体生长、纤维素合成、基质消耗的动力学模型。采用Origin6．0软件对实验数据进行处理，得到了巴氏醋酸杆菌分批发酵合成细菌纤维素的动力学模型参数。对实验数据与模型进行比较，结果表明模型与实验数据能较好地拟合，基本上反映了巴氏醋酸杆菌分批发酵过程的动力学特征。     

Multivariate data analysis in classification of must and wine from chemical measurements

A chemometric study was carried out; based on measurements of chemicals present in musts and wines from the Tacoronte-Acentejo Designation of Origin area (Canary Islands, Spain) obtained in an artisanal winemaking procedure. Univariate and multivariate data analysis was used to distinguish between two different harvest years (1987 and 1988) in both musts and wines. The data was examined using the statistical techniques of discriminant analysis, principal component analysis, biplot analysis and factor analysis, which allowed the study of the underlying structures of the data and the characterization of the wines. This methodology was able to differentiate between musts and wines according to traditional variables used in wine analysis. However, no clear differentiation was found with respect to the year of vintage.     

Relationships between sensorial characteristics and microbial dynamics in "Registered Designation of Origin" Salers cheese

Raw milk cheeses show a wide diversity of sensorial characteristics, largely determined by the microflora of raw milk. Microbial dynamics in Registered Designation of Origin (R.D.O.) Salers cheese was assessed by DNA and RNA SSCP analysis on nine cheeses. These cheeses showed considerable diversity both in microbial dynamics and sensorial characteristics. Relationships between the sensorial characteristics and the microbial dynamics were studied. A global consideration of bacterial dynamics demonstrated that other bacteria than lactic acid bacteria can play a role in the elaboration of sensorial characteristics. Indeed, high CG% Gram-positive bacteria can be involved. DNA data, as well as RNA data, appeared relevant to attempts to explain sensorial variance. Correlations between sensorial and microbial data were rather complex. Several microbial variables for DNA and RNA analyses, noted at different times of analysis, were correlated to each sensory variable. A global view of cheese microbial community proved to be insufficient in explaining the diversity of the sensorial qualities of R.D.O. Salers cheese.     

标准女体胸围曲线研究

采用法国力克公司生产的非接触式智能三维人体测量仪,测量18例22～25岁体型接近160/84A的健康女性人体,并截取过乳头部位的胸围曲线,以5°定1个点,借助MatLab7.0编程计算,得到18例女体胸围曲线上的平均点坐标,即标准女体胸围点坐标.在此基础上,运用origin软件对标准女体胸围点坐标进行曲线方程拟合,在确...     

降解游离棉酚的热带假丝酵母菌的发酵动力学研究

对降解游离棉酚的热带假丝酵母菌的发酵动力学进行了研究.通过Logistic方程,以干物质损失量表示生物量,建立了热带假丝酵母菌固态发酵过程中菌体生长、总糖消耗和游离棉酚含量的动力学模型,应用Origin 8.0对实验数据进行处理,得到了热带假丝酵母菌固态发酵的模型参数.动力学分析结果表明,动力学模型与实验数据能较好地拟合,基本上反映了热带假丝酵母菌固态发酵过程.     

An international ring trial for the sensory evaluation of raw ewes’ milk cheese texture

A total of nine Protected Designation of Origin hard and semi-hard cheese varieties were selected for this study, all made with raw ewes’ milk. The cheeses selected were Idiazabal and Roncal from Spain, Ossau-Iraty from France, and Pecorino Sardo, Pecorino Romano and Fiore Sardo from Italy. This ring trial was designed as a first step to validate a consensually designed standardized guide for ewes’ milk hard and semi-hard cheese texture evaluation and assess main differences among five sensory panels using this guide. Several univariate and multivariate statistical techniques were employed for data treatment. Each of the sensory attributes was relevant and understood similarly by all the panelists. The sensory attributes more relevant to the discrimination of the cheeses were friability, adhesiveness, solubility and moisture in mouth. The development of standardized and consensual sensory tools has been proven to provide consistent results among the participating panels.     

论品级与色特征级的辩证关系

文章以新疆棉花检验数据为例,使用Origin7．0软件进行数据统计分析和绘图处理,分析探讨色特征检验与棉花品级的联系与区别。     

Classification of some heat-treated liver pastes according to container type, using heavy metals content and manufacturer's data, by principal components analysis and potential curves

A total of 115 pork liver pastes were randomly collected in local markets from different brands, countries and containers. The concentrations of nine heavy metals (Cu, Ni, Cd, Fe, Mn, Pb, Cr, Co and Zn), determined by atomic absorption spectrometry, and some qualitative variables described on the labelling constituted the data set. Chemometrics analysis was performed combining principal components analysis (PCA), factor analysis (FA) and typical classification techniques, such as linear discriminant analysis (LDA) and potential curves (PoCu) to classify pork liver pastes. Origin of the sample, manufacturer and effect of manufacturing process were taken into account to verify traceability, which is an important issue in food safety policies.     

Influence of manufacturing conditions and discrimination of Northern Spanish cheeses using multi‐element analysis

Thirty‐three samples of cheeses belonging to different Protected Designation of Origin (PDOs) located in Northern Spain were analysed with the aim of studying the influence of processing conditions on the minerals and trace elements content in cheeses. The use of sheep milk, animal rennet, salting by immersion in a brine bath and ripening in cheeses reported, in general, the highest levels of trace elements. Moreover, pattern recognition analysis of multi‐elemental data, based on mineral and trace element content, was used to determine geographical traceability and to detect possible imitations with a correct classification in 98.5% of cases.     

Origin软件在能力验证数据报告图示制作上的应用

能力验证是对参加实验室检测/校准能力和管理体系运行状况进行客观考核,促进其能力提升的一种有效手段。目前,主要采用稳健四分位法对能力验证数据进行统计分析,运用Excel、MATLAB等软件制作能力验证数据报告图示。Origin是一种公认的简单易学、操作灵活、功能强大的科学绘图与数据分析软件。它基于模板绘图,软件本身提供了几十种二维和三维绘图模板而且允许用户自己定制模板。Origin的数据分析主要包括统计、信号处理、图像处理、峰值分析和曲线拟合等。本文以"葡萄酒中铜和胭脂红的测定"(CNCA-14-B08)能力验证项目各参加实验室提交的铜含量数据为例,详细介绍了使用Origin软件制作z比分数柱状图、重复测定结果偏差棒图、检测结果分布频率直方图、z值直方图和尧敦图的方法。