Robust Ionic Liquid–Based Dispersive Liquid–Liquid Microextraction Method for Determination of Chromium(VI) in Saline Solutions

Robust ionic liquid–based dispersive liquid–liquid microextraction (IL-DLLME) is a fast and simple method for extraction and preconcentration of metal ions from samples with high salt content. This method can solve the problems associated with the limited application of the conventional IL-DLLME in these samples. In this procedure, the hydrophobic chelate of chromium with ammonium pyrrolidinedithiocarbamate (APDC) was extracted into the fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF₆]), which was dispersed into the aqueous sample solution. Several factors that influence the microextraction efficiency were investigated. In optimum conditions a linear calibration graph in the range of 0.5–70 μg L^?1 of Cr in the initial solution with r = 0.9998 was obtained. Detection limit was 0.16 μg L^?1 and relative standard deviation (RSD) for 20 μg L^?1 of Cr was 2.68% (n = 10), respectively. The proposed method was successfully applied for the determination of Cr(VI) in water samples and food additives.     

铬对肉仔鸡生长性能、血清生化特性、免疫功能和胴体品质的影响

用294只3周龄Arbor Acres(AA)商品代肉公鸡进行试验,研究玉米-豆粕型基础日粮中添中两种铬源（三氯化铬和酵母铬）及4个铬添加水平（0、0.4、2.0和10.0mg/kg）对肉仔鸡生长性能、血清生化特性、免疫功能和胴体品质的影响。试鸡共分7组（两铬源共用零添加组）,试验期3周。结果表明,三氯化铬在提高肉仔鸡饲料转化效率及法氏囊相对重量上比酵母铬更有效（P < 0.10）,其余多数性能指标在两铬源间无显著差异(P > 0.10);日粮中添加2.0和10.0mg/kg水平铬可显著提高肉仔鸡的血清新城疫抗体效价和胸肌率(P < 0.05),铬水平对其余多数指标无影响(P > 0.10);除胸肌率(P < 0.03)外,其余指标均未观测到铬源与铬水平的互作(P > 0.10)。     

螺旋藻富铬及其含铬蛋白组份对α-葡萄糖苷酶抑制的研究

在富铬Z氏培养液的条件下,研究了钝项螺旋藻对Cr(Ⅲ)的吸收及其有机化程度,采用不同饱和度硫酸铵沉淀的方法分离提取不同蛋白组份,对其含Cr(Ⅲ)量进行了分析,并探讨了蛋白组份对α-葡萄糖苷酶活性的抑制作用.结果表明,螺旋藻培养液中CrC13·6H2O添加浓度为300mg·L-1,螺旋藻总铬富集量可达到3.30mg·g-1,有机化程度为70.2％;不同饱和度(25％、50％和75％)硫酸铵沉淀出的蛋白组份中铬占总铬的情况分别为2.1％、16.8％和7.0％,不同蛋白质结合铬的能力各异;3种蛋白组份对α-葡萄糖苷酶均有抑制作用,其中50％饱和度硫酸铵沉淀的蛋白组份抑制活性最高,IC50为69.87mg·mL-1.     

花溪河水中铬(VI)污染分析

在分析微量元素铬与健康的关系的基础上,采用二苯碳酰二肼光度法测定花溪河水中的铬（VI）,得到花溪河的准确的铬污染参数。并以此为依据分析河水中的铬（VI）来源、评价其影响并积极探讨其治理方式、方法。     

铬胁迫对大豆种子萌发和幼苗生长的影响

[目的]为预防大豆早期铬伤害提供依据。[方法]用不同浓度的铬处理大豆种子,研究铬对大豆种子萌发率、发芽势及幼苗生长的影响。[结果]随着Cr6+浓度从0增至5mg/L,发芽率从91.44%增至92.59%,发芽势从89.13%增至89.54%。Cr6+浓度从10mg/L增至160mg/L时,发芽率和发芽势分别降至74.94%和73.64%。低浓度铬处理的大豆幼苗根长、芽长及生物量比对照有少许的增加。15mg/L的Cr6+抑制大豆幼苗的生长,且随着浓度的提高抑制效应逐渐增强。Cr6+浓度达到100mg/L时,根长与芽长分别为对照的28.61%、31.33%。Cr6+对大豆幼根生长的抑制作用大于对芽生长的抑制作用。[结论]铬处理对大豆种子萌发及幼苗生长具有一个低浓度下的刺激效应和高浓度下的抑制效应,浓度10mg/L以下的铬对大豆种子萌发及幼苗生长有促进作用。     

米泉、红雁池鲢鱼体内总铬含量的分析

对米泉地区和红雁池鲢鱼体内的总铬含量,用二苯胺基脲比色法在721分光光度计上进行测定,结果米泉地区鲢鱼体内总铬含量为0.631ppm,经统计学处理,P<0.05,两地鲢鱼体仙总铬含量具有显著差异。     

Dietary nano chromium picolinate can ameliorate some of the impacts of heat stress in cross-bred sheep

Two studies were conducted to evaluate the effect of nano chromium picolinate (nCrPic) during heat stress (HS) in sheep. In the initial study, 36 Merino × Poll cross-bred sheep were individually penned and allocated to 3 dietary treatments (0, 400 and 800 μg/kg nCrPic) for 8 wk. Body composition was determined at the beginning and end of the experiment using dual energy X-ray absorptiometry. The sheep remained in their dietary groups but were then placed in metabolic cages and randomly allocated within the dietary group to differing ambient temperature regimes, i.e., thermo-neutral (TN) (n = 18) and HS (n = 18), for 3 wk. Dietary nCrPic had no effect on growth performance and body composition during the initial study conducted under TN conditions. Heat stress decreased average daily feed intake (ADFI) (P = 0.002) whereas sheep under HS had reduced average daily gain (ADG) and indeed lost weight (P < 0.001). Dietary nCrPic increased both ADFI (P = 0.041) and ADG (P = 0.049) under both TH and HS conditions such that the performance of sheep receiving supplemental nCrPic and exposed to HS was similar to that of control sheep maintained under TN conditions. Heat stress increased rectal temperature (P < 0.001) and respiration rate (P < 0.001), particularly during the hottest parts of the day as indicated by interactions (P < 0.001) between time of day and thermal treatment. Rectal temperature was lower in sheep fed nCrPic (P = 0.050), particularly under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and time of day (P < 0.001) and dietary nCrPic, thermal treatment and time of day (P = 0.010). Similarly, respiration rate was lower in sheep fed nCrPic under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and thermal treatment (P < 0.001) and dietary nCrPic and time of day (P = 0.030). In conclusion, dietary nCrPic can partially ameliorate the negative effects of HS as indicated by the maintenance of ADFI and decreased physiological responses, such as elevations in rectal temperature and respiration rate.     

重金属复合胁迫条件下夏玉米铬元素空间残留研究

采用盆栽形式系统研究了Cr、Cd、Pb、Hg、As 5种重金属元素复合胁迫下玉米植株中铬元素的空间残留。结果表明,玉米各部位铬元素残留浓度随胁迫浓度提高先升后降,呈抛物线变化,处理浓度为2K左右时出现峰值。不同基因型处理间铬元素的吸收存在差异,高油115不但在叶片、茎秆中而且在单株中铬元素平均残留浓度高于费玉3号。在铬元素的空间分布中,对照处理之间各部位差异不显著,1K胁迫浓度下除下部叶外其余部位差异不显著,2K、3K、4K处理各品种铬元素的残留为叶片>茎秆,其它部分浓度低。叶片中铬的残留浓度以下部叶>中上部叶片,中上部叶片之间差异不显著。茎秆中铬的残留浓度与叶片中铬的残留浓度规律相似。子粒与其它(轴和苞叶)铬残留浓度随重金属复合胁迫浓度提高略有增加,但浓度低于叶片和茎秆,处理之间差异不显著。     

烟酸铬对西门塔尔牛精料瘤胃降解率的影响

试验选用4头平均体重500±20kg,年龄4岁,装有永久性瘤胃瘘管的西门塔尔牛阉牛,采用4×4拉丁方试验设计,以混合精料和风干玉米秸秆为基础日粮,研究1.3倍维持水平下,日粮添加烟酸铬（0mg/d、40mg/d、80mg/d、120mg/d）对精料瘤胃降解率的影响。结果表明：日粮添加烟酸铬组DM有效降解率与对照组差异不显著（P〉0.05）,添加80mg/d烟酸铬组精料OM有效降解率、CP瘤胃有效降解率较对照组显著提高（P〈0.05）。本试验结果表明：日粮添加烟酸铬的适宜添加水平为80mg/d。     

Cr(Ⅵ)污染生物修复研究进展

首先介绍了我国Cr(Ⅵ)污染的状况及毒性,然后重点介绍了铬污染生物修复技术的特点以及研究现状,包括铬污染水体的微生物还原、微生物吸附、植物吸附,以及铬污染土壤的微生物还原及植物修复.相对于植物修复而言,微生物在治理Cr(Ⅵ)污染水体及土壤方面都具有非常大的应用潜力,值得进行更深入的研究.