皮革及其制品中富马酸二甲酯的测定

采用脱水乙酸乙酯对皮革及其制品中的富马酸二甲酯进行超声提取,用气相色谱/质谱联用仪进行定性定量测定,并进行了线性、回收率、精密度等试验。结果表明:方法线性范围在0.05~100mg/L,相关系数为0.9999,方法的检测下限为0.05mg/kg,回收率在82%～87.5%,相对标准偏差RSD(n=5)小于5%,能很好地应用于皮革及其制品中富马酸二甲酯残留量的检测。     

D72型树脂催化合成邻苯二甲酸二甲酯

用D72型阳离子交换树脂作为苯酐与甲醇反应合成邻苯二甲酸二甲酯的催化剂，研究了催化剂的用量、物料配比、反应温度、反应时间等因素对酯化反应的影响．结果表明：当催化剂的质量分数为4％，n(苯酐)：n(甲醇)：1：3，反应温度为110℃，反应时间为6h时，反应的酯化率可达99％。     

THE MEASUREMENT OF DIMETHYL SULPHOXIDE IN BARLEY AND MALT AND ITS REDUCTION TO DIMETHYL SULPHIDE BY YEAST

Dimethyl sulphoxide (DMSO) is a normal component of malt and barley. A method is described for its extraction and estimation. DMSO is produced by the oxidation of dimethyl sulphide (DMS), particularly during kilning of malt, and higher levels are found in malts subjected to ale kilning schedules. DMS may also be oxidized during wort preparation. DMSO can be reduced to DMS by yeast in glucose/salts medium, by yeast cell suspensions and by a cell-free extract. Reduction of DMSO is inhibited by methionine sulphoxide. The results suggest that reduction of DMSO may account for the DMS produced during fermentation of ale and lager worts.     

Crystalline complex between poly(γ-methyl l-glutamate) and dimethyl phthalate

The crystalline complex between poly(γ-methyl l-glutamate) (PMLG) and dimethyl phthalate (DMP) has been formed in films cast from a solution in dichloroethane. It has the stoichiometry of 1 mol of DMP to three or four residues of PMLG and shows two definite characteristics in X-ray diffraction patterns; one is the large hexagonal unit cell with the edge of around 28 Å and another the ‘extra’ 5.07 Å meridional reflection which can not be interpreted by a PMLG α-helical conformation. The structural examination for the films with various DMP contents is carried out by X-ray, viscoelastic, and d.s.c. measurements and the following structure is proposed for the crystalline complex. Four PMLG are associated to form a group which is hexagonally packed and DMP molecules, located in the gaps between groups, form a specific favourable helical structure along PMLG chains in which the van der Waals stacking of benzene rings of DMP is significant.     

高效液相色谱-串联质谱法测定豆制品中的二甲基黄残留量

目的建立高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定豆制品中的二甲基黄的含量。方法豆制品经乙腈超声提取,经色谱柱Thermo C_(18)Acclaim RSLC分离,采用乙腈:水(85:15,V:V)作为流动相进行等度洗脱;质谱(electronic spray ion,ESI+)采用多离子监测模式(multiple reactions monitoring,MRM)对二甲基黄的定量离子和定性离子进行监测。结果本方法在5 min内可完成二甲基黄的分离分析。二甲基黄在10~500μg/L范围内具有良好的线性关系,在50、100和200μg/L 3个添加水平下的加标回收率为90.2%~94.2%,相对标准偏差为0.926%(n=9),方法的检出限为0.4μg/kg。结论该方法快速准确、灵敏度高,可适用于测定豆制品中二甲基黄的残留量。     

QuEChERS-超高效液相色谱-串联质谱法快速测定豆制品中二甲基黄和碱性嫩黄O的含量

目的建立QuEChERS结合超高效液相色谱-串联质谱法(QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry,QuEChERS-UPLC-MS/MS)快速测定豆制品中二甲基黄和碱性嫩黄O的含量。方法豆制品经20 m L乙腈-水(1:1,V:V)浸泡,采用QuEChERS方法进行萃取、净化,经Shim-pack XR-ODSⅢ色谱柱分离,正离子扫描,多反应监测模式进行质谱分析,外标法定量。结果二甲基黄在添加水平为0.5、1和10μg/kg时,方法回收率为81.6%~97.2%;碱性嫩黄O在添加水平为6、10和50μg/kg时,方法回收率为89.1%~100.7%;二甲基黄和碱性嫩黄O的相对标准偏差均小于12%(n=6);二甲基黄和碱性嫩黄O的检出限分别为0.5、2μg/kg;定量限分别为1.5、6μg/kg。结论该方法操作简便、快速准确,适用于豆制品中二甲基黄、碱性嫩黄O的快速筛查和定量分析。     

新型聚酯聚醚共聚型亲水整理剂的合成及其性能

以间苯二甲酸二甲酯-5-磺酸钠(SIPM)为改性单体,合成一种新型聚酯聚醚共聚型亲水整理剂.研究SIPM添加量,缩聚反应温度、时间,催化剂用量对整理剂水溶性和亲水性能的影响,优化合成工艺条件.用FT-IR、热重分析仪、X射线衍射仪对整理剂结构和性能进行研究,并对其应用性能进行探讨.结果表明:当SIPM摩尔用量为二元酯(...     

DETERMINATION OF DIMETHYL SUPLHIDE IN BEER BY GAS CHROMATOGRAPHY — COLLABORATIVE TRIAL

The Analysis Committee has collaboratively tested both routine headspace gas chromatographic methods and a standardised method for the determination of dimethyl sulphide in beer using the flame photometric and flame ionisation detectors available in the participating laboratories. The mean repeatability value (r₉₅) was 7.8 μg/litre for the concentration range 12–65 μg/litre, and the reproducibility value (R₉₅) showed the relationship R₉₅ = 18.1 + 0.452m μg/litre to the concentration (m). No differences in precision were attributed either to the methods or the types of detectors used.     

氮-磷-氯型皮革阻燃复鞣剂的合成及应用

选取亚磷酸二甲酯与丙烯酰胺在甲醇钠的催化作用下反应,制得中间体3-二甲氧磷酰基丙酰胺,后再利用中间体与环氧氯丙烷反应,合成出具有复鞣性能的氮-磷-氯皮革阻燃复鞣剂。讨论了反应物配比、反应温度、反应时间等条件对聚合反应的影响,确定了最佳反应条件:中间体与环氧氯丙烷的摩尔比为1.0:1.5,反应温度为100℃,反应时间为6h。将该合成的阻燃复鞣剂施加于皮革复鞣工段,利用阻燃检测法测试皮革的阻燃性能,试验发现,所得皮革制品的氧指数、有焰燃烧时间、无焰燃烧时间、烟密度、燃烧速率,均比未施加阻燃复鞣剂有显著提高,且所得制品在感官指标和力学方面,均比未施加阻燃复鞣剂的皮革有显著提高。     

固相分散萃取-液相色谱法测定豆沙中的富马酸二甲酯

采用固相分散萃取技术对豆沙样品进行预处理,用高效液相色谱法测定其中的富马酸二甲酯。Diamonsil C18色谱柱,柱温25℃,甲醇-水（体积比为55∶45）作流动相,流速1.0mL/min,检测波长220nm。富马酸二甲酯在0.136μg/mL～33.5μg/mL范围内线性良好,相关系数为0.9998,方法检出限0.82μg/g,平均回收率82.5%,相对标准偏差为3.3%。市售豆沙馅中未检出富马酸二甲酯。