氧瓶燃烧-离子色谱法测定芥蓝中氯、氮、硫元素的含量

采用氧瓶燃烧将来自揭西红脚芥蓝和潮州脆肉芥蓝中的氯、氮、硫转换为阴离子,利用离子色谱测定这几种离子的含量,通过对来源不同的芥蓝中阴离子含量分析得出不同的生长环境对芥蓝中氯、氮、硫的含量的影响。     

原子吸收光谱法测定营养盐中钾、钙、铁、锌

营养盐试样用盐酸溶解,采用原子吸收光谱法测定钾、钙、铁、锌。对仪器条件及干扰进行了试验,方法的精密度为2.61%~4.66%,加标回收率为98.3%~101.4%。     

吡蚜酮在大棚和露地芥蓝上的残留消解动态

[目的]比较大棚和露地条件下吡蚜酮在芥蓝的消解动态和最终残留差异,为其在芥蓝上的合理使用提供数据支持。[方法]样品经乙腈提取,经石墨炭净化,采用电喷雾正离子源和多反应监测模式检测。在0.02、0.2、2.0 mg/kg的3个添加水平下,吡蚜酮的平均回收率为91.7%～95.8%,相对标准偏差(RSD)为2.2%～3.7%。[结果]吡蚜酮的残留量与其栽培方式有关,在露地芥蓝的半衰期为7.1 d,而在大棚的半衰期为8.8 d,在露地上10 d可降解80%以上;而大棚却要在14 d以上。[结论]吡蚜酮在大棚条件下使用时比在露地使用时更加难以降解,降解半衰期更长。     

化学试剂络合对改性活性炭吸附痕量铂、钯的影响

为了更准确地测定土壤中的铂、钯,在体积分数为5%的盐酸介质中,选用不同试剂为络合剂,改性活性炭为吸附剂,电感耦合等离子体质谱法测定土壤中的铂、钯。实验研究表明:经盐酸羟胺改性的活性炭富集,铂、钯的回收率为92.3%~102.4%;8-羟基喹啉为络合剂时,铂的回收率为86.4%~104.9%,钯的回收率为91.7%~100.0%;抗坏血酸为络合剂时,铂的回收率为82.6%~100.9%,钯的回收率为86.2%~98.3%;硫脲为络合剂时,铂的回收率为78.2%~105.1%,钯的回收率为81.9%~95.3%。方法检出限:铂为0.017 ng/mL,钯为0.021 ng/mL。该方法操作简便,分析速度快,灵敏度高,具有良好的测定精密度和准确度,适用于超痕量铂、钯的分析。     

一种高抗冲、低浮纤长玻纤增强聚丙烯材料

本发明公开了一种高抗冲、低浮纤长玻纤增强聚丙烯材料,由下述重量百分比的组份构成,长玻纤增强聚丙烯母粒10%~80%,高抗冲、低浮纤母粒20%~90%;所述长玻纤增强聚丙烯母粒的构成为:共聚聚丙烯8%~80%,均聚聚丙烯0~80%,玻纤10%~60%,接枝聚丙烯1%~10%,抗氧剂0.1%~2%,加工助剂0.2%~2%;所述高抗     

顶空气相色谱法同时测定地表水中的乙醛、丙烯醛

采用顶空气相色谱法测定地表水中乙醛、丙烯醛的含量,优化的顶空条件为:平衡温度80℃,平衡时间20 min,加Na Cl添加量4 g,样品量10 m L。水中乙醛、丙烯醛的最低检出限分别为0.05和0.08 mg/L,乙醛加标回收率为84.8%~109.1%,丙烯醛为79.2%~108.3%;乙醛相对标准偏差为2.4%~8.6%,丙烯醛为5.2%~10.7%。     

高效液相色谱法测定不同配伍比例甘草、威灵仙药对中甘草苷、甘草酸的含量

目的:建立测定不同配伍比例甘草、威灵仙药对中甘草苷、甘草酸的含量的方法,探讨不同配伍比例配伍的药对的合理性。方法:色谱柱Agilent 20RBAX XDB-C18(4.6 mm×250 mm,5μm)流动相为乙腈(B)-0.1%磷酸盐溶液(A),洗脱方式为梯度洗脱,0~10~19~20~24~70~75min,乙腈(B)为:15%~25%~25%~32%~80%~15%,0.1%磷酸盐溶液(A)为:85%~75%~75%~68%~20%~20%~85%。检测波长254 nm,流速为1 m L·min~(-1),柱温为室温,进样量20 L。结果:配伍比例为4∶1时,甘草苷、甘草酸含量分别为:10.67 mg·g~(-1)、30.54 mg·g~(-1)。甘草苷在0.0123~0.04305 mg·m L~(-1)浓度内呈良好线性关系,回归方程Y=509.31X-0.237,R2=0.9998;甘草酸在0.03684~0.12897 mg·m L~(-1)浓度范围呈良好线性关系回归方程Y=493X+0.6841,R2=0.9982。甘草苷、甘草酸平均回收率分别为97.50%,97.10%。结论:最佳的配伍比例为4∶1。     

电感耦合等离子体发射光谱仪测定工业硝酸中的钴、铈、镧含量

采用ICP等离子体发射光谱仪测定工业硝酸中的钴、铈、镧等元素,快速、准确。该方法加标回收率为94.9%~105.6%,相对标准偏差为1.16%~3.56%,最低检出限达到0.000 594~0.000 987 mg/L。     

ICP-OES法测定食品添加剂磷酸中铬、铜、镍、铅、锰、镉、钛

建立了电感耦合等离子体发射光谱法测定食品添加剂磷酸中铬、铜、镍、铅、锰、镉、钛的方法。主要考察了分析线选择、仪器工作条件选择、校准曲线及检出限、精密度、加标回收率等指标。研究结果显示,该法精密度为0.32%~2.51%,加标回收率为95.8%~102.0%,测定结果与原子吸收光谱法测定结果基本一致,满足实验分析要求。     

气相色谱法测定抗氧剂中对甲酚、2,4酚、264的含量

研究了抗氧剂264的烷基化产物的气相色谱分析,对不同类型的色谱柱进行了筛选,全面考察色谱分析的各种条件及影响因素,建立了OV-1毛细管柱分离,以内标法定量的分析法,结果准确,对甲酚回收率为99.1%~103%,2,4酚回收率为98.5%~100%,264回收率为97.2%~99.5%。     

离子色谱法同时测定环境样品中的甲酸、乙酸、氯乙酸

采用离子色谱法同时测定环境样品中的甲酸、乙酸、氯乙酸,简便快速,准确性较好,灵敏度较高。甲酸、乙酸、氯乙酸的检出限依次为0.030,0.096,0.574μg/mL(S/N=3),在1~20μg/mL浓度范围内均呈现良好的线性关系,相关系数(r)均大于0.998。将三种目标物定量加入到空白水样中,甲酸、乙酸、氯乙酸加标回收率均在95.04%~105.46%范围内,其RSD值均在1.65%~3.12%之间。结果表明,该法可应用于雨水、地下水、地表水等环境样品中甲酸、乙酸和氯乙酸的测定。     

能量色散X射线荧光光谱法同时测定涂料中的铅、铬、镉、汞

建立了用能量色散X射线荧光光谱法同时测定涂料中的铅、铬、镉、汞的一种新的测试方法。实验结果表明,各待测元素在25-200mg/kg范围内,线性关系良好;铅、铬、镉、汞的检出限分别为13、7、4、9mg/kg;回收率在91.8%-101.6%之间;相对标准偏差在1.2%-4.3%之间。同国家标准规定的测试方法相比,本方法缩短了测试时间,更简单,但其准确度、检出限完全可以满足涂料中铅、铬、镉、汞含量的半定量分析,可广泛应用于涂料重金属检测当中。     

油漆、胶粘剂中三苯检测方法的改进

采用GC-MS的分析方法分析油漆、胶粘剂样品中苯、甲苯和二甲苯的含量,克服了传统方法中保留时间定性造成的定性错误,考查了方法的准确度和精密度,三种组分的回收率在97-105%之间,五次测定的相对标准偏差小于4%。     

粤东第一温泉中硫化氢、氯、硬度、碳酸氢根、碳酸根、氟的测定

采用离子选择性电极分析法等方法测定粤东第一温泉水中的硫化氢、氯、硬度、碳酸氢根、碳酸根和氟。测定结果为:H2S3.878mg/L、Cl-445.878mg/L、硬度25.1271mg/LF-1.16mg/L、HCO3-103.7.mg/L、CO32-20.40mg/L,RSD1.29%-2.01%,回收率97.9%-101.5%     

ICP-AES同时测定降水中的钾钙钠镁

采用ICP-AES法对降水中的钾钙钠镁金属离子进行了测定,结果表明:各元素线性相关性均大于0.9990,加标回收率为94.4%～102.6%,相对标准偏差为0.41%～3.05%之间,均可满足要求。相比于火焰原子吸收分光光度法,该方法具有前处理简单,干扰少,测定准确、快速等特点。     

Integral bread development with soybean, chia, linseed, and folic acid as a functional food for women

Six bread formulations were developed, using different proportions of whole-wheat flour, chia seeds and flaxseed flour. All of our formulations were added with folic acid. Sensorial and texture evaluations were performed, showing good acceptance of the products. Proximal chemical analysis was carried out; in addition, the following parameters were determined: calcium, phosphorus, total dietary fiber, folic acid, water hydration capacity, Glucose Dialysis Retardation Index (GDRI) and fatty acids. The results obtained showed higher protein levels in the developed breads (23.23-30.24 (g/100g dry matter) as compared to a control (21.00% of proteins in bread elaborated without chia or flaxseed). Furthermore, the breads contained 10.07-12.15 of lipids (g/100g dry matter) (linoleic acid: 2.43-4.05%; linolenic acid: 1.12-4.46 %; oleic acid: 2.93-6.13 %), GDRI values were between 89.1 and 98.1 % and folic acid was in the range 699.44 - 991.3 (microg/100g dry matter). The same parameters were determined in the chia seed and in the flaxseed flour. It was concluded that; due to their high levels of protein, insaturated fatty acids (omega-3 and omega-6), dietary fiber and folic acid, these breads have a high nutritional value, so they could have special benefits for woman.     

DUO-ICP-AES测定精对苯二甲酸中的钴、铬、铁、锰、钼、镍、钛

采用DUO-ICP-AES同时测定精对苯二甲酸中钴、铬、铁、锰、钼、镍、钛,并对仪器的分析线选择、背景校正、入射功率、雾化器压力、辅助气流量、冷却气流量、蠕动泵转速的影响及共存元素的干扰、硝酸铯灰化助剂等因素进行了详细的研究。方法的检测限:钴0.0097 mg/L;铬0.0021 mg/L;铁0.0078 mg/L;锰0.0012 mg/L;钼0.0027 mg/L;镍0.016 mg/L;钛0.0027 mg/L,回收率和精密度分别为93.0%～99.5%和0.37%～3.2%。该方法快速简便,具有良好的精密度和准确度,适用于进出口精对苯二甲酸的日常检验。     

火焰原子吸收光谱法测定广西甜茶中的微量元素

火焰原子吸收光谱法测定广西甜茶根、茎和叶中的Ca、K、Na、Mg、Cu、Fe、Zn和Mn的含量。标准曲线的相关系数为0．9955—0．9996,相对标准偏差为0．53％-2．02％,加标回收率为97．7％～103．3％,结果表明广西甜茶含有丰富的微量元素。     

Tomato Seed Oil I Fatty Acid Composition,Stability and Hydrogenation of the Oil

Tomato seed oil was investigated to study their components of fatty acids, stability and hydrogenation conditions. The estimation of the fatty acids of tomato seed oil from Ace variety and tomato seed oil extracted from local waste in comparison with cotton seed oil (the most familiar edible oil in Egypt) - Giza 69 variety - extracted by n-hexane and oil obtained by pressing shows that more than 50% of the total fatty acids are linoleic. Palmitic acid was found in a range between 20% to 29% and oleic acid was in a range between 13% to 18%. Other fatty acids like stearic, arachidic, and linolenic acid were less than 3%. The induction periods (at 100°C) for oils of fresh, roasted and stored tomato seeds were found to be 7, 10, and 5 hours respectively. The hydrogenation conditions of crude tomato seed oil were 180°C, 3 kg/cm² and 0.2% nickel catalyst for three hours of hydrogenation to reach a melting point of 50.7°C and an iodine value of 42.     

Compositional disorder and sintering of entropy stabilized (Hf,Nb,Ta,Ti,Zr)B2 solid solution powders

Entropy-stabilized (Hf,Nb,Ta,Ti,Zr)B₂ solid solution powders produced by a carbo/boro-thermal reduction followed by solid solution formation were first analysed by synchrotron radiation x-ray diffraction, and their long range periodicity (i.e. lattice parameters) as well as the micro-strain intended as lattice disorder were quantitatively determined. A model to describe the micro-strain was proposed. The as-synthesized (Hf,Nb,Ta,Ti,Zr)B₂ solid solution powders were then hot-pressed at 2200 K and 50 MPa until near full densification was achieved. The hot-pressed material had a residual micro-porosity of 1.3 vol.% and consisted of a (Hf,Nb,Ta,Ti,Zr)B₂ ceramic matrix, 0.3-1 μm grain size range, and of a residual 10 vol.% B₄C particulate component, grain size in the range 0.2-2 μm. B₄C was a side product of the former synthesis and, after hot-pressing, remained trapped along the grain boundaries of the primary (Hf,Nb,Ta,Ti,Zr)B₂ solid solution ceramic matrix. Micro-hardness HV_0.2 = 22.7 ± 1.9 GPa for 1.96 N applied force was measured.