COD实验室消解温度差异性研究

应用重铬酸钾法,比对了在不同温度条件下,高低浓度样品中COD含量测定的差异性。通过对准确度,精密度的比对等实验分析得出,低浓度样品COD测定值总体随温度的升高而降低,高浓度样品COD测定值总体随温度升高而升高,且在200℃下,样品的测定值与真值最为接近,为今后样品加热条件选择上做参考。     

采用不同方法对食品中砷元素检测的比较

目的:对食品中砷的检测方法和不同仪器的测定结果进行比较与探索。方法:参照国标GB/T 5009.11-2003方法,使用岛津AA-6800型原子吸收分光光度计、AFS-8330双道原子荧光光度计两个仪器,采用两种不同的前处理方法分别测定食品中的砷,进行比较。结果:原子荧光光度计测定结果平行进样RSD小于2%,标准曲线时相关系数能达到0.999以上。原子吸收分光光度计测定结果平行进样RSD小于3%,标准曲线时相关系数能达到0.99以上。结论:原子荧光光度计相对于原子吸收分光光度计在对低浓度的样品检测中数值更加准确。     

藏香中总汞的含量及其燃烧迁移率测定

利用冷原子吸收直接汞分析仪测定了藏香中的总汞含量及其燃烧迁移率。粉碎的藏香样品及燃烧后灰烬直接称量、测定,无需其它样品前处理,6min内完成一个样品分析。该方法检出限可达0.007ng,线性范围:0.007ng～5.0ng,相关系数可达0.9999,测定优敏芭藏香(红)中总汞含量为17.0ng·g~(-1),相对标准偏差为4.8%(n=7),加标回收率在86.4%～99.9%之间。同时测定环境标准物质结果与参考值相符。所测7种藏香样品燃烧后总汞的迁移率均大于99.7%.此方法灵敏度高、精密度好、回收率高、无需样品前处理、简单省时。     

凤仙花幼苗对铅和铬的抗性研究

<正>point采用水培试验方法,用不同浓度的铅和铬复合溶液处理凤仙花种子,研究铅和铬对凤仙花种子的发芽率、幼根、幼芽和根系活力的影响。结果表明,一定浓度范围的铅和铬溶液有利于凤仙花种子萌发,而高浓度的铅和铬溶液抑制凤仙花的生长发芽,且这种抑制作用随着浓度的增加逐渐增强;低浓度铅和铬溶液     

拓展醚化汽油中醚类含量的测定范围

基于SH/T 0663-1998《汽油中某些醇类和醚类测定法气相色谱法》标准,针对醚化汽油,考察了高浓度甲基叔丁基醚(MTBE)和叔戊基甲基醚(TAME)的测定条件,采取加入稀释剂的方法使样品稀释后的MTBE和TAME含量在SH/T 0663-1998的测定范围之内。采用稀释法测定高含量的MTBE和TAME准确度高,精密度好,能够满足装置高浓度样品的分析需要。     

我国常用肥料产品重金属含量测定与分析

样品采用湿法消解进行处理,并用电感耦合等离子体质谱(ICP-MS)法测定黑龙江省地市售常用肥料中主要重金属的含量中5种重金属元素(Cr、As、Cd、Hg、Pb)的含量。实验结果表明:五种不同类型肥料的范围值相比较,有机肥料中铬元素含量最高,微量元素水溶肥料中砷元素和镉元素含量远高于其他肥料,而过磷酸钙中的汞元素和铅元素含量最高。     

石墨消解—ICP-MS同时测定土壤中的五种重金属元素

建立以HNO3—HF—H2O2为消解剂,石墨消解系统前处理样品的方法,采用电感耦合等离子体质谱仪(ICP-MS)同时测定土壤中铜、铅、锌、镍、铬的含量。结果表明:石墨消解能将土壤样品消解完全,ICP-MS测定土壤标准样品的结果均在保证值范围内、相对标准偏差在0.92%~4.00%之间,具有较好的精密度。该方法操作简单,准确度高,适合大批量样品同时测定。     

决明子生芽转化有机铬的效果研究

利用透析方法将不同时间点收获的富铬决明子芽中的有机铬和无机铬分开,用石墨炉原子吸收分光光度法测定富铬决明子芽中的总铬含量和无机铬含量,计算出各时间点收获的决明子芽的有机铬转化率。探讨决明子生芽转化有机铬的效果。培育时间对决明子芽有机铬转化率有一定影响,在本实验条件下,72h是培育富铬决明子的适宜时间段。     

火试金分离富集、ICP-OES联合测定烟尘中的金、银含量

正在铜冶炼过程中产生较多的烟尘,其中有铜、金、银、硫、砷、铅、锌、铋、镍、铬等多种元素,因样品中的铋会对铅试金分析测定金银含量会产生严重的干扰。本文通过实验,确定了最佳的实验条件和分析方法,消除了样品中的铋对灰吹过程的干扰,实现了采用铅试金富集、ICP-OES联合测定烟尘中的金银含量。该方法的RSD%在     

不同贮藏方式对野菜主要成分的影响

通过对荠菜、蒲公英、苣荬菜3种野菜分别进行冷藏、冷冻、常温放置处理，并对鲜样及处理后植株叶片中蛋白质、维生素C、胡萝卜素、硝酸盐进行测定。结果表明：贮藏后野菜中蛋白质、维生素C、胡萝卜素含量低于鲜样，硝酸盐含量高于鲜样。     

伊犁新垦区土地利用和地形对表层土壤养分变异性的影响

本文基于野外实测剖面数据,借助于数理统计方法探讨了采样点尺度上土地利用和地形因子（海拔、坡度和坡向）对伊犁新垦区表层土壤有机质、全氮、全磷和全钾含量分布特征的影响。结果表明：①土地利用类型对表层土壤的有机质、全氮和全磷有显著性影响,而对全钾的影响不显著;②不同地形因子对表层土壤养分要素影响的显著性各异。4种养分含量与海拔呈极显著正相关,在500～600m梯度平均含量均最低,600～700m梯度波动范围均最大;有机质、全氮和全钾在高海拔梯度的平均含量高于低海拔的含量,全磷的平均含量随着海拔升高呈倒U型分布;③有机质和全氮与坡度呈显著正相关,3°以上的平均含量显著高于3°以下;在坡度〈1.82°时,4种养分含量的波动范围最大;④全磷与坡向呈显著负相关;阴坡的各种养分因子的平均含量不同程度的高于阳坡的含量;除全钾外,各种养分因子在阳坡的波动范围均大于阴坡的范围;⑤土地利用类型与地形条件的交互作用对表层土壤养分含量存在影响。在不同地形条件下,不同土地利用类型间的表层土壤养分含量高低情况存在差异,表现在较高海拔、较大坡度和阴坡上中覆被草地的有机质含量明显高于农田和低覆被草地,而在较低海拔、较小坡度和阳坡上则情况相反。     

Some factors in the Nessler method of nitrogen determination

It has been shown that the amount of sulfuric acid used in the digestion of samples for the determination of nitrogen by the Nessler method may have a decided effect on the final color intensity. When 5.0 ml. of Nessler reagent are used for color development, a straight-line relationship between colorimeter readings and nitrogen concentrations is obtained, provided not more than 0.3 ml. of 1:1 sulfuric acid is used for the digestion. Furthermore, the method described herein can be applied to a wide range of nitrogen concentrations, from 5 to 400 micrograms, by appropriate choice of filters.     

A study of serum lipid profile part-1: Establishment of normal reference values of serum lipid levels in healthy vegetarian population of Gujarat

Fasting samples of 1329 apparently healthy vegetarian Gujarati population were tested for total cholesterol, triglycerides and three major fractions of lipoproteins, i.e. high density lipoproteins, low density lipoproteins and very low density lipoproteins. All the values showed marked increase with the age. Except for serum triglycerides, values differ in males and females in the age group of above 45 years. Compared to Northern Indian population low density lipoprotein and high density lipoprotein values were higher, but values of triglycerides and very low density lipoproteins were lower. There is no significant difference in total cholesterol values. Compared to Southern Indian population low density lipoprotein and very low density lipoprotein values were higher but values of triglycerides, total cholesterol and high density lipoprotein were lower. All serum lipid values were significantly lower than the Westem population. The range of values for both the sexes is presented for different age groups.     

Effect of n-3 fatty acid supplementation on blood glucose, lipid profile and cytokines in humans: A pilot study

This study was undertaken to evaluate the effects of n-3 fatty acid supplementation on blood glucose, lipid profile and cytokines in humans. Twenty adult healthy subjects were supplemented with 1g/day fish oil concentrate capsules for 2 weeks. Fasting blood samples were taken at baseline and again after 2 week intervention. Fish oil supplementation significantly lowered fasting serum concentrations of total cholesterol, triacylglycerol, very low density lipoprotein and low density lipoprotein (P < 0.01). Also high density lipoprotein increased significantly compared with baseline value (P < 0.01). Fish oil did not significantly altere the fasting blood glucose concentration but significantly reduced the serum cytokines (P < 0.001). This study demonstrated that eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) supplementation altered serum lipids, lipoprotein and cytokine concentrations in normal human subjects even at the small dose of 660 mg of EPA plus DHA per day. It appears that EPA plus DHA can be a safe and perhaps beneficial supplement to inflammatory diseases.     

铬矿石中铬含量的快速分析方法

以磷硫混酸对铬矿石样品分解试样,在银盐存在条件下,用过硫酸铵氧化,以N-苯基代邻氨基苯甲酸作指示剂,用硫酸亚铁铵标准溶液滴定。不仅操作简单,分析速度快,分析结果准确,且分析成本低,更适合大批量样品的高效分析。     

Stimation of reference interval of lipid profile in Assamese population

12hrs fasting samples of 1485 apparently healthy, Assamese population in the age group of 20–80 yrs., mostly from the urban area of Assam were tested for serum lipid profile that includes total cholesterol, triacylglycerol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) over a period of three years. The values (median and range in mg/dl) obtained were 170 (93–263); 110 (40–256); 40 (23–73); 103 (40–173) and 22 (8–51) respectively. After grouping these subjects according to the age and sex no significant difference were observed between most of the groups. Median and upper range of total cholesterol, HDL-C and LDL-C were found to be higher in women than in men in all the age groups. But triacylglycerol and VLDL-C concentrations were observed to be higher in the men than women except in age group of 61–70 yrs. It can be suggested that lipid values obtained in this study can be used as the reference value, based on which clinical correlation can be made.     

危险废物焚烧残渣中铜的浸出特性研究

为了达到危险废物焚烧残渣中重金属的减量化和资源化,本试验针对残渣中高含量的Cu,考察残渣中Cu的浸出特性,为其减量化和资源化提供基础。试验样品经过消解后测其中各重金属含量,发现其中Cu含量高达(21016±4)mg/kg,浸出毒性高出危险废物安全填埋标准的20±2倍,故本试验拟用浸提法对其进行减量化,以达到安全填埋的标准。采用盐酸、硫酸、EDTA和柠檬酸铵对Cu进行浸提回收,结果发现硫酸的浸提效果最好,最佳浸提条件为浓度0.25 mol/L、固液比1∶10、浸提时间为1.5h,浸提效率可达87%;研究还显示加入氢氟酸后,Cu浸提效率可高达96%。因此,通过化学浸提剂的浸提,不仅可以大大减少残渣中Cu的含量,降低环境二次污染的风险,同时有利于金属Cu进行资源回收,具有一定的经济价值。     

Role of ascorbic acid in human seminal plasma against the oxidative damage to the sperms

This study evaluated the extent of oxidative stress by measuring malondialdehyde and ascorbic acid in the seminal plasma of human subjects with different fertility potential. Semen samples from 148 subjects were evaluated (48 normozoospermics, 34 oligoasthenoteratozoospermics, 34 asthenoteratozoospermics and 32 azoospermics). malondialdehyde level was found to be significantly higher in the abnormal groups (oligoasthenoterato and asthenoterato-zoospermics) than normozoospermics (P < 0.01). Negative correlation was also found between malondialdehyde level, sperm concentration, sperm motility and sperm morphology. Level of ascorbic acid was found to be significantly higher in normozoospermics than other abnormal groups (P < 0.01). It was found to be correlated positively with all seminogram parameters and negatively with malondialdehyde level. The study revealed that, excess lipid peroxidation reflected by high malondialdehyde level with reduced ascorbic acid in human seminal plasma is associated with poor semen quality where as ascorbic acid content has positive correlation with fertility potential.     

烟片处理工艺参数与切丝含水率相关性研究

为了解和掌握叶片处理段工艺参数与切丝含水率的相关关系,采用一元线性回归分析方法对叶片处理段工艺参数松散回潮累计加水量、叶片加料累计加水量、叶片处理段加水总量及贮叶时间与切丝含水率的相关性进行了分析,描述了叶片处理工艺参数与切丝含水率的相关性,建立叶片处理工艺参数与切丝含水率均值的一元线性方程。结果表明,松散回潮累计加水量及叶片处理段累计加水量与切丝含水率均值相关性较强,一元线性回归方程较为显著;叶片加料加水累计量及贮叶时间与切丝含水率均值不具有相关性;贮叶时间对烟片加料含水率与切丝含水率的差值相关性较强,一元线性回归方程较为显著;叶片加料出口含水率与切丝含水率相关性较强。