首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
毛细管气相色谱法测定牛奶中有机氯和有机磷农药残留量   总被引:18,自引:0,他引:18  
王兆基 《分析化学》1998,26(2):158-161
采用一个较快速、简单的方法测定牛血中有机氯和有机磷农药残留物。牛奶中农残经氯仿萃取和固相提取净化后,分别用气相色谱-电子捕获检测器和气相色谱-火焰光度检测器直接测定,色谱柱为HP-1接HP-5、DB17大口径石英毛细管柱。本法对17种有机氯农残的回收效率范围为71.2% ̄99.7%,检测限为0.5 ̄9μg/kg。而11种有机磷农残的回收率范围为70.1% ̄96.1%,检测限则为0.01 ̄0.04m  相似文献   

2.
牟峻  李庆才 《分析化学》1997,25(1):69-71
确立了粮谷和油籽中氯苯胺灵残留量的气相色谱测定方法,试样采用甲醇提取,经与正己烷液液分配,再以弗罗里硅土柱净化,毛细管柱气相色谱-氮磷检测器测定。方法简便、准确、检出限0.02μg/g,添加回收率为87.5-92.9%,相对标准偏差为3.5-7.0%。  相似文献   

3.
牟峻  张琪 《分析化学》1997,25(12):1401-1403
确立了坚果及其制品中匹克司残留量的气相色谱测定方法试样采用甲醇提取,经PT-硅镁柱净化,GC-ECD测定,方法简便,快速灵敏,检出限0.02*10^-3g/kg,添加回收率87.4%-93.2%,相对标准偏差4.4%-6.88%.。  相似文献   

4.
用大口径毛细管柱气相色谱法测定蜂蜜中杀虫脒残留量   总被引:2,自引:0,他引:2  
蜂蜜中杀虫脒残留量用气相色谱-氮磷检测器(GC-NPD)直接测定,色谱柱为HP-5大口径毛细管柱,方法的回收率为78.3%~92.5%,变异系数为4.2%,最低检测限2×10-9。样品前处理采用了微量化学法。  相似文献   

5.
周黎明  曲刚莲 《分析化学》1996,24(2):125-129
本文用气相色谱-微波诱导等离子体原子发射光谱检测器(GC-MIP-AED)对水中微量路易氏剂的水解产物的测定方法进行了研究,在酸性条件下,路易氏剂的水解产物与2,3-二巯基丙醇(BAL)迅速反应形成挥发性的衍生物,在480.192,181.379和189.042nm波长下分别检测了衍生物的氯,硫,砷元素的发射信号,最小检测量为0.1μg/L。回收率为87.2%~97.4%。  相似文献   

6.
张海涛  莫丽儿 《色谱》1999,17(3):262-263
用0.4mmol/LH2O2处理HL-60细胞株24h,采用气相色谱/氢火焰检测器检测DNA氧化损伤产物8-羟基鸟嘌呤,并用气相色谱-质谱仪选择性离子检测对其进一步鉴定。所用方法的平均回收率为81.7%,RSD小于5%。  相似文献   

7.
范小振  丁天惠   《色谱》1994,12(1)
研究开发的一种新型的元素光度检测器主要用于锗、砷、锡和锑的氢化物气相色谱检测,具有高灵敏,高选择性。它是在普通火焰光度检测器的基础上加装了特制的滤光片改制而成的。对锗、砷、锡和锑的检测限分别为3.0×10 ̄(-11)g、7.0×10 ̄(-11)g、7.0×10 ̄(-10)g和1.1×10 ̄(-8)g,相对标准偏差分别为1.8%、2.4%、2.6%和3.0%。  相似文献   

8.
土壤中绿黄隆残留量分析方法的研究   总被引:2,自引:0,他引:2  
向文胜  苏少泉 《分析化学》1994,22(6):605-608
本文确立了土壤中绿黄隆残留量的间接气相色谱分析方法,用0.15mol/L NaHCO3提取土样,二氯甲烷洗涤初步纯化后,在水浴上加热水解,再用二氯甲烷萃取,弗罗里硅土柱净化,最后用气相色谱-电子捕获检测器检测水解产物邻氯苯磺酰胺。土壤中添加回收率78.5%-90.8%,检测极限0.3ng/g。  相似文献   

9.
范小振  丁天惠 《色谱》1994,12(1):8-10
 研究开发的一种新型的元素光度检测器主要用于锗、砷、锡和锑的氢化物气相色谱检测,具有高灵敏,高选择性。它是在普通火焰光度检测器的基础上加装了特制的滤光片改制而成的。对锗、砷、锡和锑的检测限分别为3.0×10 ̄(-11)g、7.0×10 ̄(-11)g、7.0×10 ̄(-10)g和1.1×10 ̄(-8)g,相对标准偏差分别为1.8%、2.4%、2.6%和3.0%。  相似文献   

10.
衍生化气相色谱—质谱法测定水中的路易氏剂及砷酸   总被引:4,自引:1,他引:4  
本文研究了用气相色谱-质谱法测定水中微量路易氏剂及砷。在酸性条件下,路易氏剂及水解产物2,3-二巯基丙醇迅速反应形成挥发性的衍生物,大大提高了测定灵敏度。用选择性离子检测定量,最小检测量为每升水中1μg,路易氏剂的加标回收率为95.62%~105.88%之间,砷的加标回收率为96.35%~106.03%之间。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

13.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

14.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

15.
16.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

17.
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.  相似文献   

18.
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.  相似文献   

19.
A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).  相似文献   

20.
Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO4 oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号