粮食、饲料中尿素酶活性测量结果不确定度的评定

对粮食、饲料中尿素酶活性测量结果的不确定度进行了评定。使用酸度计，利用pH增值法，以pH增量表示尿素酶活性。通过对影响样品测试过程的不确定度分量的分析和量化，求得尿素酶活性测量结果的标准不确定度和扩展不确定度分别为0．019、0．04，并对测量结果进行了表述。     

超临界流体萃取—气相色谱法测定粮谷和茶叶中有机氯农药残留量

介绍了一种用超临界流体萑取进行样品前处理，用吸附小柱进行富集和净化，气相色谱－电子捕获检测器定粮茶叶中１７种有机氯农药残卵留量的方法。对于ＳＦＥ的温度，压力，流速以及吸附小柱的吸附剂类型和用量，洗脱条件等均作了考查。     

云南省白族长寿区谷类粮食中19种元素含量的测定

采用电感耦合等离子体发射光谱法,对云南省白族长寿区的大米、玉米和黄豆中的１９种元素进行了测定。结果显示,在３种谷类粮食中,均含有人体必需的３种常量元素Ｍｇ、Ｐ、Ｓ及４种微量元素Ｃｒ、Ｍｎ、Ｆｅ、Ｚｎ其中Ｐ、Ｓ、Ｍｇ、Ｆｅ、Ｚｎ的含量最高,其次是Ｍｎ、Ｃｒ。     

粮食水分的测量和电子水分仪测量不确定度的评定

介绍粮食中水分的两种测量方法：烘干称重法和电测法。同一台水分仪测量不同品种的粮食可能有不同的不确定度,一台水分仪要存入多条工作曲线用以测量不同品种粮食的含水量。介绍了电子水分仪测量不确定度的评定方法。     

Combined biocompatible medium with molecularly imprinted polymers for determination of aflatoxins B1 in real sample

A kind of molecularly imprinted polymers modified with biocompatible medium was prepared by suspension polymerization. The obtained hybrid materials were used as the adsorbents for the solid‐phase extraction of aflatoxins B1 in real samples. A structural analog of the target, 6‐methyl‐4‐phenylchroman‐2‐one was used as the pseudo‐template, owing to their lower toxicity and cheaper price compared with aflatoxins B1; and methacrylic acid and glycidyl methacrylate were used as the co‐monomers. Scanning electron microscopy and size distribution analysis were used to characterize the obtained polymers. The extraction parameters were optimized to achieve the desired extraction performance. The polymer solid‐phase extraction coupled with high‐performance liquid chromatography was successfully applied to determine aflatoxins B1 from soy sauce without the process of protein removal. Under the optimum extraction conditions, the detection results of aflatoxins B1 in lab‐made column in soy sauce samples was carried out, with a recovery rate of 96%. The established method presented a linear range from 10 to 1000 ng/mL with the coefficient of determination of 0.9994 and the limit of detection of 0.05 ng/mL. Likewise, the inherent selectivity of lab‐made column towards aflatoxins B1, Ochratoxin A, and Zearalenone was demonstrated.     

Complex formation in aqueous medium of partially hydrolysed oat cereal proteins with sodium stearoyl-2 lactylate (SSL) lipid surfactant and implications for bile acids activity

Sodium stearoyl-2 lactylate (SSL) lipid surfactant molecules specifically bind partially hydrolysed oat proteins in aqueous medium and significantly enhance the dispersion stability of oat cereal preparations. The proposed complexation is composition dependent and a greater understanding of the role of both oat proteins and lipid surfactant in the effect was gained with data from high performance liquid chromatography (HPLC–UV), viscometry and differential scanning micro calorimetry. The effect of the lipid surfactant on the degree of association is primarily governed by the conformational activity of oat protein molecules related to the extent of protein hydrolysed state, as well as protein unfolded and subsequent aggregated structures. SSL does not dissociate oat proteins into subunits or destroy important hydrophobic contacts already stabilising the protein molecules. Although the exact mode of association is unknown, the present study demonstrates that such interactions occur in a specific manner and suggest selectivity of oat proteins for individual fatty acids. The effect of various amounts of bile acids on SSL–oat protein interaction was also investigated, as a first attempt to investigate the role of lipid surfactant molecules in the known cholesterol-lowering action of oat cereal ingredients and to elucidate favourable conditions by which oat cereal can elicit hypocholesterolemic effects.     

液相色谱-串联质谱法测定谷物类饲料中的41种激素

建立了谷物类饲料中10种雄性激素、11种孕激素、10种糖皮质激素、5种雌性激素以及5种二羟基苯甲酸内酯类药物的液相色谱-串联质谱(LC-MS/MS)检测方法。均质样品经乙酸乙酯提取,以改良的QuEChERS吸附剂分散于提取液中实现快速净化。采用C18色谱柱(150 mm×2.1 mm, 3.0 μm)分离,分别在正、负电喷雾串联质谱多反应监测模式下检测。在优化条件下,41种化合物在5.0～200.0 μg/kg含量范围内有良好的线性相关性,相关系数均不低于0.99,定量限(S/N≥10)为0.123～2.72 μg/kg。在5、40、200 μg/kg或10、40、200 μg/kg 3个添加水平下,豆粕类饲料中各化合物的回收率为70.3%～118.1%,相对标准偏差(RSD)为0.82%～19.5%;玉米类饲料中各化合物的回收率为76.1%～122.8%, RSD为1.3%～15.0%。该方法简便、快速、准确,可用于谷物类饲料中雄性激素、孕激素、糖皮质激素、雌性激素以及二羟基苯甲酸内酯类激素的筛查和测定。     

超高效液相色谱-串联质谱法测定粮食中有机磷酸酯及其二酯代谢物

建立了粮食样品中14种有机磷酸酯(OPEs)及其8种二酯代谢物(di-OPEs)的超高效液相色谱-串联质谱分析方法(UPLC-MS/MS).样品以甲醇为溶剂超声萃取后,直接加载到活化后的ENVI-18固相萃取柱中,萃取液用5 mL甲醇洗脱,合并洗脱液氮吹定容后进样分析,采用内标法定量.22种目标物在0.1～20μg/L...