库化分析法测定饲料中的痕量砷

饲料工业标准GB13079—91中规定了总砷的测定方法，利用碘化钾、氯化亚锡将高价砷还原为三价砷，然后与由锌粒和酸反应生成的新生态氢作用生成砷化氢，经银盐溶液吸收后，形成红色络合物，与标准系列比较定量。这种方法属于一种半定量方法，准确性不高。目前砷的测定通常?..     

异烟酸-巴比妥酸分光光度法测定畜禽饮用水中氰化物

采用异烟酸-巴比妥酸分光光度法测定畜禽饮用水中氰化物的含量.畜禽饮用水中氰化物经蒸馏后被碱性溶液吸收,与氯胺T的活性氯作用生成氯化氰,再与异烟酸-巴比妥酸试剂反应生成紫蓝色化合物,进行比色定量.结果,在0～0.240mg/L范围内,具有良好的线性关系(r=0.9996),平均回收率为97.9％～99.2％.该方法成熟、准确,可用于畜禽饮用水中氰化物的检测.     

异烟酸—巴比妥酸分光光度法测定畜禽饮用水中氰化物

[目的]采用异烟酸-巴比妥酸分光光度法测定畜禽饮用水中氰化物含量。[方法]畜禽饮用水中氰化物经蒸馏后被碱性溶液吸收,与氯胺T的活性氯作用生成氯化氰,再与异烟酸-巴比妥酸试剂反应生成紫蓝色化合物,进行比色定量。[结果]在0～0.240mg/l范围内,具有良好的线性关系(r=0.9996),平均回收率为97.9%~99.2%。[结论]该方法成熟,准确,可用于畜禽饮用水中氰化物的检测。     

银盐法测定饲料中总砷含量的方法改进

目前,不少饲料厂家在饲料中添加有机砷制剂。有机砷从动物体排出后,在自然界很快降解成无机砷而污染环境,且环境一旦污染,其残留时间很长,难于治理。许多科学家已呼吁限制此类药物作为饲料添加剂使用,因此,砷含量的检测已显得越来越重要。1测量原理样品经干灰化或酸消化处理后有机物被破坏,砷以离子状态进入溶液,经碘化钾、酸性氯化亚锡还原为三价砷后,被锌与盐酸反应生成的新生态氢还原为砷化氢,在密闭装置中被二乙基二硫代氨基甲酸银-三乙胺-氯仿溶液(以下简称Ag-DDTC吸收液)吸收,形成黄色至棕红色的胶状银溶液,其颜色深浅与砷含量成正…     

如何测定饲料中的无机砷

如何测定饲料中的无机砷杭州市饲料产品质量监督检验站袁谦我国饲料卫生标准中砷的允许量标准是以测定总砷计算，总砷是指三价、五价的无机砷及有机砷的总量。但各种价态与形态的砷化物的毒性相差悬殊，据报导，其毒性依次为砷化氢＞三价无机砷＞五价无机砷＞有机砷。元素...     

原子吸收法测定饲料级碱式氯化铜中砷(Ⅲ)和砷(Ⅴ)

用氢化物发生(HG)-原子吸收光谱法(AAS)解决了新型铜源饲料级碱式氯化铜中的三价砷和五价砷的测定。在20%的盐酸介质中,砷(Ⅲ)生成气态氢化物,而砷(Ⅴ)不发生反应;用碘化钾和抗坏血酸还原砷(Ⅴ)为砷(Ⅲ),同法测总砷,用差减法求得砷(Ⅴ)含量。方法检出限0.12μg/l,相对标准偏差(RSD)为0.46%。回收率为97.2%￣103.4%。     

饲料中砷的危害及两种检测方法的比较

砷为饲料中有毒有害物质的来源之一．对动物及人体有毒害作用．是我国饲料卫生环境控制中重要指标之一,因此,准确测定饲料中的总砷含量尤为重要。本文对国标中规定两种饲料中砷的检测方法（氢化物-原子荧光法与银盐法和二乙氨基二硫代甲酸银分光光度法）进行分析比较。数据显示．氢化物-原子荧光光度法与银盐法在O～50wg／L的范围内线性关系良好,相关系数分别为0．9999、0．9989;最小检测限分别为0．043mg／L,0．229μg／L;平均回收率分别为99．0％、96．5％;精密度（CV％）分别为2．16％。3．20％,实验证明传统的银盐法灵敏度和精密度相对较低．操作繁琐费时,试剂毒性大且测试周期长：而氢化物原子荧光光度法操作简便、快速,灵敏度高,选择性好,是一种较好的测定砷分析技术。值得推广应用。     

硼氢化物还原光度法测定预混料中总砷方法的改进

硼氢化物还原光度法测定预混合饲料中总砷含量 ,是通过将样品经酸消解或干灰化破坏有机物使砷呈离子状态存在 ,在酒石酸环境中 ,硼氢化钾与砷离子作用生成氢化砷 (AsH3)气体 ,在密闭装置中被Ag -DDTC三氯甲烷溶液吸收 ,形成黄色至棕红色银溶胶 ,其颜色深浅与砷含量成正比 ,用分光光度计比色测定。该方法的关键在于生成氢化砷时溶液的酸度 ,加入酒石酸溶液前 ,pH值在 4～ 5时测得值与实际值相吻合。GB/T1 30 79- 1 999方法中的酸度控制是采用在试样溶液中加入 2滴甲基橙指示剂 ,用氨水 ( 1∶1 )调pH值至橙黄色 ,再滴加盐酸溶液 ,至刚好…     

原子荧光法测定饲料添加剂硫酸锌中砷含量的探讨

目前，硫酸锌中砷的检测方法主要是HG 2934—2000《饲料级硫酸锌》中规定的砷斑法．此方法虽具有操作简单的优点．但也具有检测不精确等缺点．检测结果只能以大于或小于0．0005％来表示：此外由于不同人员的检测．对砷斑的深浅有不同判断．误差较大。本文基于此点考虑．建立了原子荧光光度计法测定饲料添加剂硫酸锌中砷含量的方法．硫酸锌样品在酸性条件下．其中的5价砷被硫脲还原为3价砷．硼氢化钠与盐酸溶液作用生成大量新生态氢．与3价砷生成砷化氢．由氩气载入石英原子化器中分解为原子态砷．在特制砷空心阴极灯发射光谱的激发下产生原子荧光．其荧光强度与砷含量成正比．与标准系列比较定量。线性范围：0～200ng／mL。经验证．此方法具有操作简单、检出限低等优点，相关系数r值≥0．9986．回收率可达到85．0％。99．9％。回收率标准偏差为：0．17％．5．00％．硫酸锌样品检测相对偏差≤1．65％等。并且不需要接触有机溶剂．可以减少对化验人员的损害。     

普鲁士蓝/石墨烯修饰电极检测畜禽饮用水中铅离子的方法和应用

为监测畜禽饮用水中铅离子的含量,对畜禽养殖场的饮用水质量进行评价,本文建立了一种基于普鲁士蓝/石墨烯修饰电极的检测畜禽饮用水中铅离子的方法.采用电化学沉淀法使石墨烯表面附着普鲁士蓝纳米颗粒,并对制备的修饰电极使用差分脉冲伏安法进行化学性质分析,以及检测铅离子在所制备的电极表面的灵敏度、稳定性和检出限,评估了试验所制备的...     

砷胁迫下老芒麦和香根草根茎叶砷吸收特征及抗氧化响应

采用盆栽试验,研究3种砷浓度下(0、10和100 mg·kg-1)老芒麦(Elymus sibiricus)和香根草(Vetiveria zizanioides)生长特征及根、茎、叶三部位砷含量变化及其细胞膜透性、抗氧化酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)]响应特征。结果表明,低浓度砷对老芒麦和香根草株高和生物量抑制不明显,高浓度下抑制显著(P<0.05),二者相比香根草对重金属砷有更好的抗性。除老芒麦叶片变化不显著外,两种植物其余部位的砷含量均随着浓度的增加而显著增加;老芒麦地上部的砷积累量随浓度的增加显著降低,香根草则表现出随浓度的增加显著升高,高浓度条件下香根草地上部的砷积累量要高于老芒麦。老芒麦根、茎、叶三部位的细胞膜透性均表现出随砷浓度增加显著升高,香根草根、叶部位表现出相同的变化趋势,但茎部的差异不显著(P>0.05)。砷胁迫引起了老芒麦根、茎、叶三部位CAT、SOD和APX活性的显著增加,而香根草这3种酶的活性能够在10和100 mg·kg-1间维持。POD活性有所不同,表现为砷胁迫引起两种植物茎、叶部位降低,根系增加。综合而言,香根草对于重金属砷有更好的抗性、更强的富集能力,并且SOD与POD可能在其抗氧化体系中起关键作用。     

生态养猪场发酵床垫料中砷残留测定

应用原子吸收方法测定不同年限、不同位置发酵床垫料中砷残留。结果表明:1年、2年、3年发酵床垫料中砷残留最大值分别是2.148、5.014、8.3353mg/kg;随着年限的增加,发酵床粪便区砷残留出现明显富集。     

Foot-and-mouth disease virus: a long known virus, but a current threat

Foot-and-mouth disease virus (FMDV) was the first animal virus identified. Since then, FMDV has become a model system in animal virology and a considerable amount of information on its structure, biology and vaccinology has been obtained. However, the disease that this virus produces (FMD) still constitutes one of the main animal health concerns. In this review, we have attempted to summarise the state of the knowledge in different basic and applied areas of FMDV research, with emphasis on those aspects relevant to the control of the disease.     

The effect of arsenic on urethan-induced adenoma formation in Swiss mice.

Female Swiss mice were exposed to sodium arsenite or sodium aresenate in the drinking water for 15 weeks at concentrations ranging from 0 to 100 micrograms/mL arsenic content. After three weeks of the 15 week exposure period, the mice were administered urethan (1.5 mg/g) intraperitoneally. Pulmonary adenoma formation was evaluated 12 weeks later. Arsenic exposure produced a protective effect with respect to tumor development. Both forms of arsenic reduced the size and number of pulmonary adenomas observed per mouse. In addition, urethan-induced sleeping times which reflect the rate of urethan metabolism or excretion remained unchanged. This suggests that arsenic exposure does not alter urethan excretion and is not a factor influencing subsequent adenoma formation of these levels of exposure.     

Experimental 3-nitro-4-hydroxyphenylarsonic acid toxicosis in pigs

Five times the recommended dose of 3-nitro-4-hydroxyphenylarsonic acid (187.5 mg kg-1) induces a pathognomonic clinical syndrome in pigs. The main clinical features are not continually present but are inducible only by exercise. From day 11 on the experimental diet a nervous syndrome was inducible. This manifested as muscle tremors and clonic convulsive episodes. Paraparesis developed by day 22 and paraplegia by day 33. Liver arsenic levels plateaued at 5.4 +/- 1.3 mg kg-1. The experiment confirms field observations that 3-nitro produces a characteristic toxicological syndrome, which is distinct from that of arsanilic acid. It also confirms that 3-nitro has a higher absolute toxicity than arsanilic acid in pigs as well as a lower margin of safety.     

几种环保添加剂对蛋鸡舍除臭效果的研究

将３０００只２０周依莎蛋鸡随机分为４个试验组和１个对照组，在４个试验组白粮中分别添加Ｂ１０－ＡＤＥ，沸石，酶制剂，阿散酸等４种环保添加剂，进行饲喂对比试验。结果表明４种添加剂均能提高日粮的消化率和Ｎ，Ｐ的利用率，减少了粪中Ｎ，Ｐ的排出量和蛋鸡的发病率，提高了产蛋率，控制有害气体的产生。４种添加剂中以阿散酸的效果最好。     

瘤胃产甲烷菌与其他微生物间的氢传递及其调控研究进展

在反刍动物瘤胃中产甲烷菌生成甲烷既造成能量的浪费又产生大量温室气体,因此减少瘤胃甲烷生成与排放是提升生产效率与维持可持续发展的要求。瘤胃内的产甲烷菌通过共生、黏附和伴生模式,分别从原虫、细菌和真菌中摄取氢,保证氢营养型甲烷生成途径的顺利进行。抑杀原虫和产氢细菌、竞争性结合氢和阻断氢生成甲烷是基于氢调控抑制甲烷生成的途径。由于瘤胃微生物的冗余和互作,降甲烷的同时,瘤胃中饲料消化可能受到抑制,且单一的氢调控往往会诱发瘤胃的适应,瘤胃的降甲烷效果仅能短时间维持。为此,需从瘤胃微生物整体出发,通过多种氢调控机制的添加剂联用及间歇饲喂、幼龄反刍动物瘤胃早期调控、甲烷生成途径关键酶调控等的综合应用,实现更优的甲烷减排。     

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) poisoning in pigs

Young pigs, six to ten weeks of age, from two unrelated swine operations were fed a grower ration obtained from a common commercial supplier. Following ingestion of the feed for approximately two weeks, pigs in both groups developed neurological disturbances characterized by blindness, ataxia, incoordination, muscle tremors, posterior paralysis, and quadriplegia. Vocalization described as “screaming” was also observed in several animals. Necropsy findings and tissue arsenic concentrations were consistent with a diagnosis of phenylarsonic acid poisoning. The liver and kidney contained an average arsenic content of 2.9 and 1.8 mg/kg (wet weight), respectively. The feed contained 38 mg of arsenic/kg corresponding to 133 mg roxarsone (3-nitro-4-hydroxyphenylarsonic acid)/kg. This level of roxarsone is approximately three to five times higher than the levels recommended for swine rations. The feed company had placed roxarsone in the ration at levels recommended for the less toxic arsanilic acid. It was assumed that the two organic arsenicals could be added to the rations interchangeably at the same level of formulation. The present investigation indicated that roxarsone is more toxic than arsanilic acid and the margin of safety in swine rations is low.     

Numerical Simulation of Combustion of Butanol Mixed Hydrogen

In order to study the combustion characteristics of hybrid fuel after butanol has been mixed with different ratio of hydrogen,AVL FIRE software is used to simulate the process of the combustion of hybrid fuel in constant volume combustion bomb.This study uses the software of CATIA to complete the creation of three dimensional model of the constant volume combustion bomb and the software of AVL FIRE to complete grid drawing and numerical simulation of combustion.According to the ratio of 5%,10%,15%and 20%which hydrogen mixed with butanol,then study on the characteristics that mean pressure,rate of heat release and so on of combustion of the four kinds of mixed fuels with different initial conditions.The results shows that the parameters of combustion characteristics of butanol mixed hydrogen:pressure,rate of pressure rise,heat release and rate of heat release are all increased with increasing of ratio of hydrogen-doped;with increasing of ratio of hydrogen-doped,the burning duration is shortened and the peak of combustion parameters is advanced.     

Aegyptianellosis,eperythrozoonosis, grahamellosis and haemobartonellosis

Aegyptianellosis, eperythrozoonosis, grahamellosis and haemobartonellosis are diseases caused by procaryotic microorganisms which parasitize the erythrocytes of a variety of animals. Differentiation between Eperythrozoon and Haemobartonella is difficult. The parasites are similar in the living state, being small cocci or rods. In stained preparations Eperythrozoon may appear to be annular. The major criterion for differentiation is the relation of the parasite to the erythrocyte. Haemobartonellae are tightly attached to the erythrocyte and are rarely seen free in the plasma. Eperythrozoa are loosely attached to the erthrocyte, can be readily disloded and are often seen free in the plasma. Aegyptianella which occurs intracellularly in an inclusion is easily differentiated from the others while Grahamella, which is rod shaped, is always intracellular and is not in an inclusion but is scattered throughout the erythrocyte's cytoplasm. These organisms are not generally pathogenic. A slight parasitemia, mild anemia and slight fever may follow infection in the intact animal. Most infected animals remain nonclinical carriers. Splenectomy of a carrier animal or infection of a splenectomized animal will produce high parasitemia; even then, the physiological disturbance is mild. The only exceptions to the general rule that infection with these organisms produces a mild disease in intact animals are infections with Aegyptianella pullorum, Eperythrozoon suis and Haemobartonella felis. Aegyptianella pullorum produces aegyptianellosis of fowl, a disease characterized by anemia, E. suis produces “icteroanemia of swine” and H. felis produces “filine infectious anemia”.