HPLC法与三氯化铁-盐酸法检测生鲜牛乳中甲醛掺假

采用高效液相色谱定量、三氯化铁-盐酸定性检测方法分别对生鲜乳中的甲醛质量分数进行对比实验研究.高效液相色谱检测方法中,以煮沸的纯净水提取样品中的甲醛,2,4-二硝基苯肼衍生,色谱柱为Agilent SB.C18,流动相为乙腈-水(65+35).测定波长为365 nm,外标定量方法回收率在87%以上.三氯化铁-盐酸定性检测方法甲醛掺假阳性样品显紫色.甲醛掺假定性检出限为5 mg/kg.三氯化铁-盐酸定性检测方法快速、灵敏、便捷,掺假现象容易判断,可以用于乳制品企业中推广.     

激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）测定锡石样品中微量元素

A method for determination of trace elements in cassiterite by 213 nm laser ablation inductively coupled plasma mass spectrometry with lithium tetraborate flux sample preparation procedure and in-situ focusing has been investigated. The relative deviations of measurement from flux sample preparation procedure and in-situ focusing are less 25% and 10%－120%, respectively.     

同位素稀释-高分辨电感耦合等离子体质谱法测定高纯石英中痕量铀不确定度的评定

根据国际标准化组织(ISO)17025的要求,对方法的有效性和测定的不确定度进行评定.本文介绍了同位素稀释-高分辨电感耦合等离子体质谱(ID-HR-ICPMS)法测定高纯石英中痕量铀方法中不确定的来源、不确定度分量的量化、标准不确定度和合成不确定度的计算原则,对计算过程所需各参数的采集和计算方法进行了评定.     

Ar-O2气体去除硅铁合金中金属杂质研究

硅铁合金在炼钢过程中被广泛用作合金剂和脱氧剂,其中含有的金属杂质Al,Ca,Ti会直接影响钢液的洁净度,因此采用顶吹Ar-O2气体的方法去除硅铁合金中的金属杂质。借助自动扫描电镜统计精炼前后硅铁合金中杂质相的形貌、成分、面积分数,通过ICP-AES测试金属杂质的含量变化。结果表明:硅铁合金原料中含有大量的金属杂质相,Al,Ca,Ti杂质含量分别为1.11%(质量分数,下同),0.31%,0.11%;吹气精炼5min时,Al和Ca的含量分别急剧降低至0.66%和0.13%;吹气精炼45min后,杂质元素去除速率变缓,精炼反应趋于平衡;吹气精炼120min时,Al,Ca,Ti含量分别降低至0.42%,0.014%,0.094%,去除率分别为62.16%,95.48%,14.54%。吹气精炼方法能有效去除硅铁合金中Al和Ca杂质,Ti杂质去除效果不明显。     

高分辨电感耦合等离子体质谱法测定煤质样品中49种痕量元素

Various trace elements, especially potential toxic trace elements such as As, Cd, Cr, Cu, Hg, Pb, Ni, Se, Tl, Zn, would be concentrated in processing of coal. Determination of these elements in coal is very important for identification of coal quality. A method is developed for determination of 49 trace elements in coal by high resolution inductively coupled plasma mass spectrometry (HR-ICPMS). Microwave acid digestion and low-temperature airproof acid digestion for sample preparation were investigated. It is shown that the low-temperature airproof acid digestion method is of lower blank, and more suitalbe for the coal sample preparation. The on-line internal standard (Rh) sample introduction is applied to compensate matrix effects in measurement by ICPMS. The method gives low detection limits (0.002-1.60 μg/g) and better relative standard deviations (0.60%-4.78%) for the determined 49 elements in coal.     

ICP-MS测定辐射环境监测样品中238U和232Th比活度实践

Monitoring of ²³⁸U and ²³²Th in radiation environmental samples including water and biota was requested by the related international and national safety guides and standards. Inductively coupled plasma mass spectrometry (ICP-MS) was applicable to determination of ²³⁸U, ²³²Th in such samples with a high sensitivity and working efficiency. Some practical aspects are presented.     

精细丝网印刷电子影响因素及实验研究

目的为了分析网版参数、印刷工艺和油墨粘度对丝网印刷过程的影响情况及影响程度。方法以印品线宽、线厚和印刷粗糙度为评价指标,根据精细丝网的印刷过程,采用静态描述法建立油墨向网孔中填墨、油墨从网孔向承印物转移以及油墨在承印物上的流平铺展的物理模型;采用实验方法探究网版参数、印刷工艺和油墨粘度对丝网印刷过程的影响;建立相同印刷条件下,各个影响因子对应的线宽数值,线宽越小,其影响程度就越大的描述模型,以对影响因子进行比较。结果结合最小网点直径与网版目数、线径的数学模型,获知网版的选择与最小网点直径有关,最小网点直径越小,所选网版就越好;在一定范围内,刮刀角度越小,刮刀压力越大,刮刀速度越大,其印品质量就越好,超出这个范围就会影响其印品质量;离网间距不宜过大,也不宜过小,在刮刀角度为60°,刮刀速度为0.08 m/s下的离网间距最佳为2mm;纳米银导电油墨粘度对印刷质量的影响不是同步变化,若追求低厚度和小粗糙度印品,则选择低粘度油墨;若追求低线宽,则选择高粘度油墨。结论精细丝网印刷质量影响程度由高到低排序为网版参数刮刀压力离网间距油墨粘度刮刀角度刮刀速度。     

纯电动车辆电磁辐射干扰整改

通过对某一纯电动车辆电磁场辐射骚扰特性(9KHz³0MHz)进行评估测试,针对测试结果进行辐射骚扰源分析,从整车角度提出相应的整改方案,整改后满足国家标准GB/T 18387-2008的要求。