原子荧光和原子吸收测定饲料中铅的对比

采用硝酸-盐酸-氢氟酸混合酸湿法消解的前处理方法,应用原子荧光光谱仪和火焰原子吸收光谱仪测定饲料中的铅,对精密度、回收率等方法评价指标进行分析,结果显示:原子荧光光谱仪和原子吸收光谱仪测定铅的含量分别为5.735、5.838 mg/kg,检测精密度分别为4.19%、3.91%,方法检出限分别是0.032μg/kg、0.098 mg/kg。2种仪器测试结果一致,都适用于饲料中铅的测定。     

原子荧光光谱法测定饲料中微量元素硒

测定微量元素硒的常用方法有荧光法、原子吸收法和比色法等,荧光法虽然准确但繁琐,不仅所用试剂DAN毒性大而且需进口;原子吸收法火焰法灵敏度低,石墨炉法有严重的基体干扰;比色法虽然简便但灵敏度低,原子荧光法是一种简便及灵敏度高的方法.用原子荧光法测定饲料添加剂及预混料中微量元素硒,硒的相对标准偏差为1.2%,检出限为0.4 ng/mL,线性范围为0～400 ng/mL,相关系数为0.999 91,回收率为96.1%～101.8%.     

氢化物发生-原子荧光光谱发测定饲料添加剂硫酸锰中的砷

本实验为建立应用氢化物发生-原子荧光光谱法测定饲料添加剂硫酸锰中砷的方法,采用超纯水直接溶解样品,用原子荧光光谱仪进行测定砷,对仪器条件、载流、还原剂、共存离子干扰等进行研究.结果表明:方法检出限为0.0502μg/L,回收率为99.2%～104.5%,相对标准偏差为0.69%.由此可得,建立的氢化物发生-原子荧光光谱法测定饲料添加剂硫酸锰中砷的分析方法具有操作简单,灵敏度高,重现性好等优点,能满足日常检验的要求.     

氢化物发生-原子荧光光谱法测定饲料添加剂硫酸锰中的砷

本实验为建立应用氢化物发生-原子荧光光谱法测定饲料添加剂硫酸锰中砷的方法,采用超纯水直接溶解样品,用原子荧光光谱仪进行测定砷,对仪器条件、载流、还原剂、共存离子干扰等进行研究。结果表明:方法检出限为0.0502μg/L,回收率为99.2%～104.5%,相对标准偏差为0.69%。由此可得,建立的氢化物发生-原子荧光光谱法测定饲料添加剂硫酸锰中砷的分析方法具有操作简单,灵敏度高,重现性好等优点,能满足日常检验的要求。     

原子荧光光谱法测定饲料中锡含量

建立了原子荧光光谱法测定饲料中锡的方法,对该方法的精密度、准确度、方法的检出限及常见离子干扰和消除方法进行了研究。结果表明,该方法相对标准偏差为2.79%～4.51%,回收率为92.4%～105.8%,检出限为0.01 mg/kg,线性范围为0～320 ng/mL。由此可看出,氢化物原子荧光光谱法可以应用于测定饲料中的锡含量。     

氢化物发生-原子荧光光谱法同时测定饲料中的砷、汞、硒和镉

研究采用消化罐消解方法,应用氢化物发生-原子荧光光谱法同时进行饲料中砷、汞、硒、镉的测定,并对各种试验条件及影响因素进行了探讨。结果表明:采用HNO3-HClO4体系在消化罐内进行湿法消解,样品消解完全且所用时间短;使用HCl作为反应介质效果良好;在一定浓度范围内4种元素的浓度与荧光响应值均有良好的线性关系;4种元素的加标回收率均在90%以上;精密度(RSD,n=11)不大于1.7%。建立的方法简便、稳定可靠,检测成本低,结果满意,可用于饲料中砷、汞、硒和铅的同步检测。     

火焰原子吸收光谱法测定混合型饲料添加剂、微量元素预混料和矿物质饲料原料中铬含量的研究

试验旨在建立火焰原子吸收光谱法测定混合型饲料添加剂、微量元素预混料、矿物质饲料原料中铬含量的分析方法。试验通过改变样品溶解体系，优选狭缝宽度、燃助比等，将混合型饲料添加剂、微量元素预混合饲料、矿物质饲料原料样品经盐酸、硝酸、氢氟酸和高氯酸溶解，于原子吸收分光光度计上进行检测。结果显示，试验方法检出限为0.000 9 mg/kg，线性相关系数为0.999 9，样品加标回收率为95.50%～103.10%；矿物质饲料原料相对标准偏差（RSD）小于5.91%，微量元素预混料RSD小于3.06%，混合型饲料添加剂RSD小于3.00%。研究表明，试验所用方法具有良好的灵敏度、精密度和准确度，可操作性强，可实现快速准确测定混合型饲料添加剂、微量元素预混合饲料、矿物质饲料原料中铬的含量。     

原子吸收分光光度法测定饲料中微量元素的注意问题

原子吸收分光光度法，又称原子吸收光谱法(AAS法)，是基于从光源发出的被测元素的特征辐射通过元素的原子蒸气时，被其被测元素基态原子吸收，由辐射的减弱程度测定元素含量的一种现代仪器分析方法。利用AAS法测定饲料中微量元素不仅简便快捷，而且准确度好。笔者在使用AAS法测定饲料微量元素的过程中．总结出了一些需要注意的问题，谨供同行参考。     

无记忆效应氢化物发生原子荧光仪测定饲料中汞的研究

试验旨在使用无记忆效应氢化物发生原子荧光仪测定饲料中汞的含量。采用联合研发的原子荧光光度计，建立一种以水为载流无记忆效应氢化物发生原子荧光法检测饲料中汞的方法。从4种混合酸中优选出HNO₃-H₂O₂(1∶1)作为消解体系，选用2 mL 220 g/L氨基磺酸溶液消除了氮氧化合物的干扰。建立的方法在0.2～1.0μg/L范围内线性良好，相关系数r=0.999 6，检出限(n=11)为0.003 1μg/L，相对标准偏差(n=7)为2.28%，加标回收率93%～99%。研究表明，试验所用方法具有灵敏度高、准确高效等优点，可实现饲料中汞含量的快速检测。     

饲料级硫酸铜中砷的原子吸收—氢化物法测定

建立了一种快速、灵敏、准确测定硫酸铜中砷含量的新方法。本法加入硫氢酸铵和盐酸羟铵使铜沉淀,过滤分离,再用原子吸收—氢化物法测定砷,避免了大量的铜干扰,使测定结果准确可靠。线形范围2～20ng/ml,相关系数R=0.9990,RSD1.64%,平均回收率96.0%～102%。     

Supplementation of broodmares with copper, zinc, iron, manganese, cobalt, iodine, and selenium

In experiment 1, 6 pregnant mares received a concentrate that contained a trace mineral premix that provided 14.3 mg Cu, 40 mg Zn, 28 mg Fe, 28 mg Mn, 0.08 mg Co, 0.16 mg I, and 0.16 mg Se/kg concentrate (group A). Seven mares received the same concentrate plus 502 mg Zn and 127 mg Cu once daily (group B). No differences (P > .05) in foal growth data, or Cu, Zn, and Fe concentrations of mare milk, mare serum, or foal serum were observed. In experiment 2, 6 pregnant mares received the same concentrate as group A (group C), and 8 mares received the same concentrate fortified with 4× the trace mineral premix (group D). Group C mares had higher serum Zn concentration at 1 day (P < 0.01) and 56 days (P < 0.04). Group C mares had higher milk Fe concentration at 28 days (P < .01), and group D mares had higher milk Cu concentration at 56 days (P < .01). Group C foals had higher serum Cu concentration at 14 days (P < .03). The results from this study provide no evidence to indicate that supplementing late gestating and lactating mares with higher dietary trace mineral levels than those recommended currently by NRC has any influence on foal growth and development, or on the Cu, Zn, and Fe concentrations of the mare milk, mare serum, or foal serum.     

Comparisons of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, and Shorthorn breeds for weight, weight adjusted for condition score, height, and condition score of cows

Breed differences for weight (CW), height (CH), and condition score (CS) were estimated from records (n = 12,188) of 2- to 6-yr-old cows (n = 744) from Cycle IV of the U.S. Meat Animal Research Center's Germplasm Evaluation (GPE) Program. Cows were produced from mating Angus and Hereford dams to Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires. Samples of Angus and Hereford sires were 1) reference sires born from 1962 through 1970 and 2) 1980s sires born in 1980 through 1987. The mixed model included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation code (PL), and breedgroup as fixed effects for CW and CS. Analyses of weight adjusted for condition score included CS as a linear covariate. The model for CH excluded PL. Random effects were additive genetic and permanent environmental effects associated with the cow. Differences among breed groups were significant (P < 0.05) for all traits and were maintained through maturity with few interchanges in ranking. The order of F1 cows for weight was as follows: Charolais (506 to 635 kg for different ages), Shorthorn and Salers, reciprocal Hereford-Angus (HA) with 1980s sires, Nellore, HA with reference sires, Galloway, Piedmontese, and Longhorn (412 to 525 kg for different ages). Order for height was as follows: Nellore (136 to 140 cm), Charolais, Shorthorn, Salers, HA with 1980s sires, Piedmontese, Longhorn, Galloway and HA with reference sires (126 to 128 cm). Hereford and Angus cows with reference sires were generally lighter than those with 1980s sires. In general, breed differences for height followed those for weight except that F1 Nellore cows were tallest, which may in part be due to Bos taurus-Bos indicus heterosis for size.     

液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量的不确定度评估

采用液相色谱-串联质谱法测定动物尿液中11种β-受体激动剂残留量,对标准溶液、体积、质谱峰面积、浓缩过程及回收率等测定不确定度因素进行了分析,通过评定各不确定度分量及标准不确定度,得出11种β-受体激动剂的扩展不确定度在0.7 ～ 1.1 ng/mL范围内.由各因素对合成不确定度的贡献比分析可知,影响较大的因素为试验回收率及标准溶液浓度.     

文山黄牛的现状与保种措施

文章阐述了文山黄牛的品种特性、现状和保种措施。文山牛保种可采用原产地活体保种,迁地活体保种和现代生物技术保种等多种方式。文山牛体型较大,性情温顺,产肉性能好、活动敏捷、结构紧凑、肌肉强健、肉品质优良、耐粗饲、适应性广、繁殖力和抗病力均较强等特点。文山牛是云南省一个地方良种,种质资源保护刻不容缓。