饲料中中性洗涤纤维和酸性洗涤纤维不同测定方法的比较

探讨不同测定方法对饲料中酸性洗涤纤维和中性洗涤纤维测定的影响。分别用花生蔓、玉米秸秆、豆粕和玉米饲料做为粗饲料、蛋白质饲料和能量饲料的代表,样品粉碎过18目筛。采用国标测定法以及纤维袋、300目尼龙袋和400目尼龙袋3种滤袋对饲料中性洗涤纤维和酸性洗涤纤维的含量进行测定。同时对于酸性洗涤纤维的测定分别采用连续测定和不连续测定两种方法进行测定。结果表明：300目尼龙袋测定花生蔓和玉米秸秆的中性洗涤纤维和酸性洗涤纤维的结果均接近用国标法测的结果;纤维袋连续测定法测玉米和豆粕的酸性洗涤纤维的结果接近国标法测的结果;用3种滤袋法测玉米和豆粕中性洗涤纤维的结果与国标法的结果差异均显著。不连续测定法测的酸性洗涤纤维所得结果比连续测定法测的结果高。     

两种葡萄糖氧化酶活力测定方法的比较

对比研究了连续分光光度法和滴定法测定葡萄糖氧化酶活力的适用范围、换算关系,并探讨了在实际应用中的可行性.研究结果表明,对于连续分光光度法和滴定法,酶活力分别在0.044～0.351 U· mL-1和1.125～5.321U·mL-1时线性关系较好;对于连续分光光度法,在此范围内可以用两点法代替标准方法进行测定;相同的样品采用滴定法测定的结果要高于连续分光光度法,两种方法测定数值的换算关系为:滴定法测定值=(连续分光光度法测定值+0.1454)×1.2868+0.3793.鉴于分光光度法在大量样品分析时更加方便,又对连续分光光度法测定发酵液酶活进行了初步研究.     

连续流动分析仪快速测定甘蔗植株全氮、全磷含量

为快速、准确测定甘蔗植株全氮、全磷含量,采用对比法,探讨连续流动分析仪测定甘蔗植株全氮、全磷含量的适用性和稳定性。结果表明,连续流动仪测定全氮、全磷标准溶液线性良好,相关系数(R2)均达0.9998以上;检出限均为0.01 mg/L,标准偏差分别在0.48%~0.68%、0.23%~0.63%之间,加标回收率分别为93.00%~106.44%、93.33%~109.00%;与常规法相比,利用连续流动分析仪测定甘蔗植株全氮、全磷含量的结果均在允许偏差范围内,说明利用连续流动分析仪快速测定甘蔗植株全氮、全磷是可行的。     

植物油脂连续精炼工艺测定研究

为及时了解油脂连续精炼工艺与设备实际运行状况，实施油脂精炼车间考核、成本预测及设备保养，确保油脂产品的质量，定期进行油脂精炼工艺测定是一条有效而经济的途径。结合200t／d植物油脂连续精炼车间工艺测定的实践，阐述油脂连续精炼车间工艺测定的方法。     

烟草中氯的AAⅢ连续流动分析仪测定改进

为了降低AAⅢ连续流动分析仪测定烟草中氯含量的偏差,考察了透析装置、测定波长和进样管流量与显色剂浓度的配比对测定结果的影响,并对AAⅢ连续流动分析仪进行了改进.结果表明:①在反应管路上添加透析装置,烟草萃取液得到净化;②在波长460 nm下测定,反应产物的吸收最大;③改进后,烟草中氯的加标回收率为94.2％ ～ 106.5％,RSD＜5％.改进后的AAⅢ连续流动分析仪适合烟草中氯含量的准确测定.     

酱中总酸、氨基酸态氮和食盐的连续测定

对酱的总酸、氨基酸态氮和食盐的测定方法进行了改进,将几个单独测定的项目合并为一个连续测定过程,测定了三个样品中的总酸、氨基酸态氮和食盐含量.结果显示,一次性连续测定法RSD在0.4%～1.9%(n=6)之间,平均回收率100.4%,具有简便、快速、准确等优点,令人满意.     

粉厂面粉含水量的连续测定

粉厂面粉含水量的连续测定邢春生　（北京市粮食科学研究所１０００５３）面粉在生产中含水量的准确测定和控制对保证面粉质量和增加粉厂的利润都有重要作用，而使用一种连续自动测控仪器也是更必要的，下面介绍一种先进的面粉水分自动连续测定仪器──近红外水分连续测定...     

连续精练机精练液的PH值测定研究

通过对连续精练液的ＰＨ值测定，找到了连续精练ＰＨ值的有效测定方法。并以此为依据，对引进的平幅连续精练机上的自动ＰＨ值测定系统进行了改造，从而解决了连续补加烧碱的难题。     

流速分布测定与连续杀菌计算方法的研究

无菌包装通常采用连续杀菌的方法。本研究为连续杀菌值的计算发展了一个方法。这个方法是通过停留时间分布测定实现的。根据停留时间测定，进而开发了连续杀菌值计算数学模型。此数学模型可用于连续杀菌值计算。为了便于在生产线上进行监测，本研究还开发了计算机程序。     

造纸废水COD连续监测可行性探讨

用COD仪对造纸废水CODc，进行连续在线监测，并研究了进水流量、进水水质及加药量对出水CODcr的影响。实验结果表明，连续测定的CODcr值与化学法测定值可以很好地吻合。     

Performance relevant to the thermophysiological wear comfort of hip protective garments,Part I: clothing area factor of hip protective garments in clothing ensembles

The clothing area factors of several hip protective garments, alone and in ensembles, were studied in this research (Part I). Two methods were used to determine the clothing factor area: the standard photography method, and a newly developed method involving 3D scanning. The results from the two methods were consistent; therefore, either method can be used to determine clothing area factors, depending on the available equipment. The methods can be used to determine the thermal insulation performance of hip protective garments and garments in ensembles, as covered in Part II of the study.     

HTLCS与HPLC测定滁菊中木犀草素、芹菜素、金合欢素方法的建立与比较

以滁菊中木犀草素、芹菜素、合金欢素为测定指标,分别建立滁菊高效薄层扫描法(HTLCS)和高效液相色谱(HPLC)测定分析方法,并对每种方法线性关系和线性范围进行考察。结果表明:建立的HTLSC和HPLC法符合要求,线性关系良好,RE3%,并且2种方法测定结果无显著性差异(P0.05)。HTLCS法和HPLC法建立方法合理,能够采用HTLCS代替HPLC法进行滁菊中木犀草素、芹菜素、金合欢素3种成分的测定。     

Antibiotic resistance of Salmonella isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in Ontario

The emergence of antimicrobial-resistant Salmonella organisms, especially Salmonella Typhimurium DT104, has been reported in many countries, including the United States and Canada. The purposes of this study were to determine the antimicrobial resistance patterns of Salmonella isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario and to determine the agreement between the agar dilution method and the microbroth dilution method for measurement of antimicrobial resistance of the isolates. Antimicrobial resistance of Salmonella isolates from hogs (n = 71), beef (n = 24), and chicken (n = 295) to amikacin, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole, and tetracycline was determined using the two methods. None of the 390 isolates were resistant to ciprofloxacin at levels of 0.125 microg/ml. All chicken and hog isolates were sensitive to amikacin, whereas all beef isolates were sensitive to both amikacin and gentamicin. Multiple antimicrobial resistance (resistance to more than one antimicrobial) was found in 29% of bovine isolates and 42% of porcine isolates using both methods for testing and in 42% by the agar dilution and 33% by the microbroth dilution methods in the chicken isolates. Overall, there was good agreement between the two test methods for resistance to most of the antimicrobials, with disagreement found in the results in 1.3% of the isolates for ampicillin and sulfamethoxazole, 8.2% for streptomycin, 5.6% for cephalothin, and 1.0% of the isolates for tetracycline. The lack of agreement between the two test methods was found mostly among the chicken isolates.     

Determination of Lead,Cadmium, Copper,and Zinc Content in Commercial Iranian Vinegars Using Stripping Chronopotentiometry

The rapid stripping chronopotentiometry (SCP) method was used to determine copper, lead, cadmium, and zinc in different kinds of vinegars (date, white grape, red grape, and apple) produced in Iran. The results of SCP were compared with graphite furnace atomic absorption spectrometry (GFAAS) as a reference method. There were no significant differences (p > 0.5) between the two methods. The range of concentration (ng/ml) of the analytes for heavy metals in different kinds of vinegars was as follows: copper (12.79–1,129), lead (3.32–253), cadmium (non-detectable concentration to 78), and zinc (26.12–3,725). The results demonstrated that it is possible to accurately determine the copper, lead, cadmium, and zinc content by direct analysis of vinegar samples using SCP method. The metal concentrations in all samples were lower than the maximum allowable limits legislated by the Institute of Standards and Industrial Research of Iran.     

Determination of water activity of canned fish using gravimetric, hygrometric and psychrometric methods

The water activity ( a _w) of canned mackerel, tuna and sardine was determined using three methods: a gravimetric and two instrumental methods. The a _w values obtained by the gravimetric method, which only requires simple laboratory apparatus, were not significantly different from the values obtained by the other two methods, and can be used to determine high a _w values.     

Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry for the Determination of Cr,Cd, Hg,and Pb in Honeys

Electrothermal vaporization dynamic reaction cell inductively coupled plasma mass spectrometry (ETV-DRC-ICP-MS) has been applied to determine Cr, Cd, Hg, and Pb in honey samples. Honey homogenate containing HNO₃ and ascorbic acid was prepared and injected into ETV for their determination by ETV-ICP-MS. The influences of instrument operating conditions and honey solution preparation on the ion signals were reported. Ascorbic acid was used as the modifier to enhance the ion signals. The background intensity at the chromium masses was reduced significantly by using O₂, at 1 mL min^?1, as the reaction cell gas in the dynamic reaction cell (DRC). As the sensitivity of analytes in homogenized honey solutions and aqueous solutions is quite different, isotope dilution and standard addition methods were used for the quantification of Cr, Cd, Hg, and Pb in the honey samples. This method has been applied to determine Cr, Cd, Hg, and Pb in several honey samples purchased from local markets. The results obtained by isotope dilution and standard addition methods were in good agreement. The method detection limits (MDLs) estimated from standard addition curves were 0.4, 0.1, 0.6, and 0.5 ng g^?1 for Cr, Cd, Hg, and Pb, respectively, in original honey samples.     

不同预处理方式对海南山柚油感官特性及抗氧化抑菌作用的影响

探究不同预处理方式对海南山柚油的感官特性、抗氧化活性以及抑菌作用的影响,以确定最适合海南山柚油的预处理方式。采用感官评定技术对不同预处理方式山柚油进行评价;应用DPPH法、ABTS法及羟基自由基清除率技术测定山柚油的抗氧化特性,并用牛津杯法测定山柚油的抑菌效果。研究结果表明,不同预处理方式能显著影响山柚油的感官品质,微波、培炒、烘烤处理均能增强山柚油的抗氧化效果;山柚油对沙门氏菌(Salmonella)有较强的抑菌作用,综合分析最佳预处理方式为微波处理。本实验为山柚油的感官特性及抗氧化和抑菌作用提供了参考,并对山柚油的预加工具有一定的指导作用。     

RP-HPLC法分析测定人参、西洋参、三七中的皂苷类化合物

利用反相高效液相色谱(reversed-phase high performance liquid chromatography,RP-HPLC)技术对人参、西洋参和三七不同方法提取物中的8种皂苷进行定量分析。采用乙醇回流、温浸法和超声辅助提取法提取3种药材中的有效成分,并结合高效液相色谱技术进行分析。结果表明:不同提取方法比较,超声辅助法所提取的3种药材中皂苷含量较高;3种五加科人参属的药材中,三七提取物中主要皂苷含量较高,人参提取物中的皂苷种类较多。     

紫外分光光度法测定发酵液中克拉维酸含量的研究

利用克拉维酸与咪唑的衍生物在312nm下具有特征吸收的原理对其含量进行测定，回收率为99．1％～101．7％，衍生后的克拉维酸稳定性较好，增加了测量的准确性，并与高效液相色谱法进行了比较，实验表明该方法具有准确、简便、快速、操作系统简单等特点，对于成品及半成品两种方法测定结果一致，是一种用于检测发酵液中克拉维酸含量的简便、快捷的方法。