压延烘干法制备用于定量分析的叠氮硝胺吸收药

为缩短叠氮硝胺吸收药组分定量分析时间,采用压延烘干法制备了样品,并与过筛烘干法制备的样品进行了比较。用液相色谱法、卡尔·费休法分别检测了两种样品的组分含量和水分含量。结果表明,压延烘干法制备样品共需要1.2h,明显少于过筛烘干法的4.5h。压延烘干法制得的样品均匀性更好,使得取样量可以由过筛烘干法的2g减少到0.2g,配制试样溶液时所需的溶剂体积减少了90%。压延烘干后的样品含水质量分数为0.06%~0.12%,低于过筛烘干法制备的样品。表明用压延烘干法制备样品,可以减少样品组分定量分析的总时间,并且可以减少废溶剂量。     

关于全水分煤样制备与燃煤全水测定的探讨

1 测定煤中全水分的国家标准 GB／T211—1996《煤中全水分的测定方法》规定,测定煤中全水分采用A、B、C、D四种方法。A、B、C三种方法中煤样的粒度均为6mm;D法分一步法和二步法：一步法粒度为13mm,测后样品弃之;二步法煤样粒度先为13mm,经低温烘干外水后,再破碎到6mm按B法烘干内水,该样品可用于制备分析试样。新标准取消了GB211—84中的快速测定法（原方法B）,取而代之以C法,且只适用于烟煤和褐煤的微波干燥。     

无纺布用阻燃粘胶纤维黄变快速测试方法

介绍了无纺布用阻燃粘胶纤维黄变测试方法的改进。改进方法采用烘箱烘干纤维样品,与原方法采用的蒸煮晾干纤维样品相比较,改进方法测试步骤简单、测试时间短,对及时指导生产工艺调控具有积极作用。     

东盟国家小食品中反式脂肪酸风险评估分析

对东盟国家小食品中反式脂肪酸的风险进行评估。方法:采用气相色谱-法质谱法检测东盟小食品中反式脂肪酸的含量,对凭祥口岸进口106份东盟小食品样品检测脂肪含量,再检测出脂肪总量的反式脂肪酸含量。小食品中脂肪含量91份样脂肪含量在10%~25%之间,102份样品反式脂肪酸含量小于0.3%(我国奶粉中的限量)。东盟国家进口小食品通过食用途径的反式脂肪酸健康风险较低,属可接受风险。     

复混肥中钾含量检测方法的改进

对GB/T 8574—2010中钾的测定方法进行部分改进,在一定程度上简化了样品的测定程序并缩短了样品测定时间。改进实验过程中称取适量试样直接置于250 m L异颈量瓶(耐热),加适量水,加热煮沸15 min;抽滤后沉淀在180℃条件下烘干45 min。本改进方法检测结果与严格按照国标法检测的结果进行t检验,分析结果无显著性差异,可在复混肥料生产钾检测过程中使用。     

磷肥中有效五氧化二磷测定方法的改进

有效五氧化二磷含量的分析方法按国家标准重量法（仲裁法）分析结果准确,但检测时间长,分析一个样品需4～5h。经过多年的摸索及在实践中的应用,采用适当提高试样提取温度、缩短提取时间、提高沉淀的烘干温度、缩短烘干时间来提高检测效率。     

ASE/福林酚比色法测定茶叶中的茶多酚

通过优化快速溶剂萃取法(ASE)条件萃取茶叶中茶多酚,同时结合国家标准方法GB/T8313-2008中的福林酚比色法对其含量进行了测定,用t检验法对ASE法与国标方法进行了检验,结果表明,两者无显著性差异,可将ASE法用于测定茶叶中茶多酚时的提取。同时用此方法对9个样品进行了测定。ASE方法快速,简便,减少人体接触试剂的机会,可用于实际样品检测。     

高效酰化催化法合成新型胆甾醇酯液晶

采用高效酰化催化法和酰氯化法分别合成了燕尾型胆甾醇酯和对称脂肪族二羧酸胆甾醇酯两类衍生物样品。采用元素分析、红外光谱、DSC、热台偏光显微镜对样品的化学结构和液晶性能进行了表征。3个对称脂肪族二羧酸胆甾醇酯样品均为胆甾型液晶,而燕尾型的支链结构对胆甾醇酯液晶的形成具有不利的影响。两种合成胆甾醇酯的酰化方法经过对比表明,高效酰化法具有反应条件温和、副反应小、不破坏反应物、产物易分离、产率高等优点,可作为胆甾醇酯液晶合成的首选方法。     

N-酰基肌氨酸钠的合成工艺现状

综述了N-酰基肌氨酸钠的合成工艺及产品分析检测方法。重点介绍了N-酰基肌氨酸钠的间接合成法(即肖顿-鲍曼(Schotten-Baumann)缩合反应方法),该方法根据反应条件可分为:水相滴加脂肪酰氯和氢氧化钠溶液法、有机溶剂-水混合相滴加脂肪酰氯和氢氧化钠溶液法和一次加入氢氧化钠溶液水相滴加脂肪酰氯法,对比讨论了3种合成方法的优缺点。同时对N-酰基肌氨酸钠产品的质量分析方法进行了比较。     

烘干法数显水分测定仪测量结果不确定度分析

烘干法水分测定仪是一种基于烘干原理直接对衡量样品表面分离物或微量水分进行计量分析的仪器。文章依据JJG 658--2010《烘干法水分测定仪国家计量检定规程》中的检定方法,并按照JJF1059-1999《测量不确定度评定与表示》规范,对数字显示水分测定仪的测量结果进行不确定度分析。     

饲料中三聚氰胺的HPLC检测方法研究

饲料样品前处理时分别考察了提取液用量、沉淀剂用量、提取时间等因素对检测结果的影响,得到最佳前处理条件:提取液为乙腈+水+5％的三氯乙酸(8mL+14 mL+20 mL),沉淀剂为2mL,超声提取时间25 min.采用HPLC法测试,外标法定量,方法的检出限为0.2μg/mL,相对标准偏差为2.44％,回收率在88.3％～94.3％之间,20min内可以完成一个样品的分析测定,建立了一种简便、快捷、准确的测定方法.     

Schnelle Mikromethoden zur GC- Bestimmung des Fettgehalts und der Fettsauren in lipdereichen Samen

Rapid micro methods for the GLC determination of fat content and fatty acid composition in seeds rich in lipids. Two methods for the rapid sample preparation for determination of fat (gravimetri cally resp. by GLC) and fatty acid pattern (by GLC) in seeds with high lipid contents arc presented and discussed. Tire adequate amount of the sample is no more than 50 mg for both methods. The first method requires several subsequent steps: grinding with Na₂S0₄ and petroleum benzine, fat determination by weighing. transmethylation by sodium methylate in methanol (time required: approx. 60 min.). The second method is an one-step method: grinding with Na₂SO₄, extraction with petroleum benzine and transmethylation by methanol and tetramethylguanidine at the same time (time required: approx. 15 min.) – the fat content is determined by converting data of the fatty acid GLC results into data of triglycerides. The analytical results for different samples are compared with those obtained by a classical reference method. In most cases the results are comparable.     

Water-based extraction of pectin from flavedo and albedo of orange peels

The extraction of pectin from orange peels has been studied at different sample to solvent ratios, different pHs and with different extraction techniques using water. The highest pectin and total nitrogen was produced by a sample to solvent ratio of 1:12.5. The amount of pectin extracted reduces as the pH increased, while the extractability of crude protein is not affected so significantly. Previous workers have found similar results. Considerably more pectin was obtained by the Soxhlet method than by microwave extraction by a factor of two, with a longer extraction duration than the microwave extraction by a factor of 240, so microwave extraction showed a much higher extraction rate (per unit time) by a factor of 120. Pectin existed mainly in the albedo, but the flavedo still contained 27% of the amount of pectin in the total extract. The total pectin yield from the dried peel was 2.2%. The combination of hand-pressure and microwave on pectin yield from flavedo was 12% better than hand-pressure alone, which was also better than microwave extraction alone.     

Supercritical Fluid Extraction and Chromatography of Lipids in Bilberry

A supercritical fluid extraction (SFE) method has been developed for the extraction of lipids in bilberry. Experimental design was used to optimize pressure, temperature and extraction time using CO₂ as solvent. Best SFE condition for total lipids was 450 bar, 60 °C and 45 min. The SFE method was compared to conventional Bligh & Dyer (B&D) extraction. The amount of fatty acid methyl esters (FAME) was found to be 4.84 ± 0.06 mg and 4.564 ± 0.003 mg per g of the freeze‐dried bilberry sample for the developed SFE and B&D methods, respectively, while the amount of total lipids was found to be 54.40 ± 6.06 mg and 65.70 ± 0.67 mg per g of sample for SFE and B&D, respectively. This discrepancy between FAME and total lipids could be explained by the presence of wax esters, sterol esters, carotenoids and phospholipids, as determined by supercritical fluid chromatography.     

重量法测定缩合磷酸铝中三聚磷酸铝含量

基于重量法,以助溶剂TP溶解缩合磷酸铝,氯化-二氯双(乙二胺)合钴为沉淀剂,考察了样品加入量,溶解时间及沉淀反应时间对测定结果的影响。结果表明,取样1 g,溶解时间2 h,沉淀反应时间15 m in,测定结果的相对标准偏差RSD=0.39%,与热失重仪器分析法(含量测定)测定结果的相对误差为0.23%,该测定方法简捷,具有实用性。     

高效液相色谱法检测水中的灭草松

使用高效液相色谱法对水源水、出厂水、管网水中的灭草松进行检测。采用固相萃取技术对1 000 mL样品进行前处理,处理后的样品氮吹浓缩为1 mL后进行分析。本方法检出限为0.0001 mg/L,相对标准偏差RSD在2%内,回收率在80%～93%间。与生活饮用水卫生标准（GB/T5750-2006）相比,此方法不需要进行繁琐的液液萃取和衍生操作,较为简单,并且能满足日常的检测分析。     

7%右旋苯氰菊酯杀虫烟雾剂的气相色谱法测定

建立了7％右旋苯氰菊酯杀虫烟雾剂的超声萃取前处理方法和气相色谱分析方法。样品溶于含有内标物的丙酮中。经超声波萃取后，用SE-30玻璃填充柱分离并用火焰离子化检测器测定右旋苯氰菊酯。考查了萃取温度和萃取时间对萃取效果的影响。方法变异系数为0．6％，回收率在98％-103％之间。     

Flaking and extrusion as mechanical treatments for enzyme-assisted aqueous extraction of oil from soybeans

Flaking and extruding dehulled soybeans were evaluated as a means of enhancing oil extraction efficiency during enzyme-assisted aqueous processing of soybeans. Cellulase, protease, and their combination were evaluated for effectiveness in achieving high oil extraction recovery from extruded flakes. Aqueous extraction of extruded full-fat soy flakes gave 68% recovery of the total available oil without using enzymes. A 0.5% wt/wt protease treatment after flaking and extruding dehulled soybeans increased oil extraction recovery to 88% of the total available oil. Flaking and extruding enhanced protease hydrolysis of proteins freeing more oil. Treating extruded flakes with cellulase, however, did not enhance oil extraction either alone or in combination with protease. Discrepancies in oil extraction recoveries were encountered when merely considering crude free fat because some oil became bound to denatured protein during extrusion and/or sample drying. Bound fat was unavailable for determination by using the hexane extraction method, but was accounted for by using the acid hydrolysis method for total oil determination. Oil extraction recovery from extruded soybean flakes was affected by oil determination methods, which was not the case for unextruded full-fat soy flour.     

Die Bestimmung des Fettgehaltes von Kartoffelfritierprodukten durch NMR

Determination of Fat Content in Fried Potato Products by NMR Since determination of the fat content by NMR in rape seed and mize is well proved it was tried to use this method for fat content determination in fried potato products (chips and pommes frites), too. At first it was found that the high water content of pommes frites requires predrying. This can remain undone for chips, if the residual water content does not exceed 3%. Measurement by NMR is only possible if the Same fat or oil of production is used as reference. Further it was found that the fat quality which deteriorates continuously during frying leads to considerable deviations in NMR measurement. This involves that the product sample, which is to investigate, has to be taken always together with the fat sample. If all these requirements are met, differences up to 4% fat can occur in comparison between NMR determination and petrolether extraction.     

溶剂提取-荧光光谱法测定微藻油脂

研究了溶剂提取-荧光测定微藻油脂的一种新的方法。通过与溶剂提取-水浴蒸干称重法比较,表明溶剂提取-荧光光谱法具有快速、简便、高效、灵敏、不受藻样不能长期保存而影响测定制约的特点,可测定藻体量较低时的低浓度油脂含量,而称重法不能测得。利用藻密度、藻干重、藻液吸光度、荧光强度、油脂之间良好的线性关系,通过溶剂提取-荧光光谱法,测得打捞的微藻油脂平均含量为10.45%,溶剂提取-水浴蒸干称重法测得微藻油脂平均含量为8.17%,结果表明溶剂提取-荧光测定法的结果比溶剂提取-水浴蒸干称重法测得值偏大,能更准确地反映真实数值。