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1.
土壤中多种有机氯及拟除虫菊酯类农药的GC-ECD测定   总被引:1,自引:0,他引:1  
气相色谱法同时测定土壤中多种有机氯及拟除虫菊酯类农药。对土壤的分析结果:有机氯农药的检出限0.001~0、003μg/mL,拟除虫菊酯类农药检出限0.008~0.02μg/mL,线性相关系数0.9978~0.9999。用y(石油醚):V(丙酮)=3:1超声波提取,有机氯农药回收率94.2%~124.0%,相对标准偏差为3.3%~8.8%(n=5);拟除虫菊酯类农药回收率95.2%~118.3%,相对标准偏差为5.7%~7.1%(n=5);方法适用于土壤样品中农药残留测定。  相似文献   

2.
用所研制的24位全自动加压溶剂萃取仪(APLE),以丙酮-正己烷(体积比为1:1)为溶剂,在100℃和10MPa条件下,对荞麦样品中残留的7种有机氯农药进行了萃取,并通过气相色谱对萃取液进行定量分析。萃取的绝对回收率为68%~126%.相对标准偏差为1.2%~14.7%,检测下限为0.051~0.18ng/g。与索氏提取法对比,相对提取回收率为116%~148%,表明萃取收率高于索氏提取法。  相似文献   

3.
建立了固相微萃取(SPME)技术结合气相色谱-电子捕获(GC—ECD)检测方法,对大连近海养殖区内海水中的痕量12种有机氯农药进行检测,以便对该水域中海产品的食品安全性进行评估。该法具有较好的线性(相关系数为0.98~0.99),检出限达0.2~7ng/L,定量下限为0.66~23ng/L,重复测定的相对标准偏差小于10%(n=3),回收率为68%~133%。对影响SPME的参数和海水中存在的基质干扰进行探讨。  相似文献   

4.
李樱  储晓刚  仲维科  李淑娟  何友昭 《分析化学》2004,32(10):1325-1328
提出糙米中38种有机氯农药、拟除虫菊酯和多氯联苯残留量的同时测定方法。用乙酸乙酯提取,凝胶渗透色谱和固相萃取净化,气相色谱.电子俘获检测,外标法定量。3个添加水平的平均回收率分别为77.3、81.4和83.8%;相对标准偏差3.8%~13.9%。有机氯农药和多氯联苯检出限为0.07μg/kg;拟除虫菊酯的检出限为0.4μg/kg。检测方法简便省时,自动化程度高,稳定可靠。  相似文献   

5.
高效液相色谱-质谱法分析测定水中氨基甲酸酯   总被引:20,自引:0,他引:20  
采用固相萃取-高效液相色谱-质谱法(LC/MS)检测研究了水中氨基甲酸酯农药残留。水样用固相萃取富集净化,环己烷+乙酸乙酯(1+1)洗脱;以甲醇-10mmol/L乙酸铵为梯度流动相,Symmetry C18柱高效液相色谱分离。电喷雾正离子模式,选择质子化氨基甲酸酯分子离子[M+H]^+为定量离子进行MS测定。结果表明,6种氨基甲酸酯组分的平均加标回收率为73.5%~89.8%;相对标准偏差为4.50%~12.6%;水样浓缩至1/2500后的检出限为0.8~3.2ng/L。本法具有非常高的选择性、灵敏度和准确度,完全能满足水中痕量氨基甲酸酯农残的高灵敏分析。  相似文献   

6.
分别采用PDMS、PDMS/DVB、CWX/DVB三种萃取头,应用固相微萃取与高效液相色谱联用技术(SPME-HPLC)分析了水溶液中的痕量酞酸二(2-乙基已基)酯(DE-HP)。实验发现,PDMS/DVB萃取头的萃取效果较其他两种萃取头理想;对SPME的萃取条件进行了优化,建立了水中痕量DEHP的SPME-HPLC分析方法,并对实际水样进行了分析。该方法的线性范围为0.62~15.60mg/L,相关系数为0.9991,检出限为0.06mg/L(3σ,n=11),相对标准偏差(RSD)为3.3%,回收率为89.9%~101.3%。  相似文献   

7.
中草药中有机氯农药和拟除虫菊酯农药残留量的测定   总被引:31,自引:7,他引:24  
建立了中草药中11种有机氯农药和8种拟除虫菊酯农药的残留气相色谱分析方法。样品用含30%丙酮的乙腈提取,用正己烷进行液液分配,提取液用弗罗里硅土柱净化,采用兰州化物所的农残Ⅱ号毛细管柱分离,用GC-ECD同时检测。在两个水平添加时的回收率(n=5)分别为78.6%~119.7%和86.5%~114.0%,相对标准偏差分别为3.6%~8.7%和4.4%~10.2%。该方法的检出限为:有机氯农药0.005mg/kg,拟除虫菊酯农药0.01mg/kg。方法用于江西中草药样品中农药残留测定,结果满意。  相似文献   

8.
肖宇郑波  张克荣 《分析化学》2007,35(11):1654-1656
建立不需形成螯合物的浊点萃取-石墨炉原子吸收法测定水中铊a田D的新方法。用浊点萃取技术富集水中铊a田D,石墨炉原子吸收法测定。经考察,浊点萃取环境水体中铊a田D的最优条件为pH12,90℃水浴2h,Triton X-114浓度2.0g/L;在优化后实验条件下,方法测定铊a田D的检出限为0.018彬L;相对标准偏差为8.89%-13.7%(C=0.1μg/L及1.0μg/L,n:7);加标回收率为98.0%-101%。本法适于水中痕量铊(Ⅲ)的测定。  相似文献   

9.
三氯乙醛在常温下加碱能快速转化为三氯甲烷,通过测量三氯甲烷建立了顶空固相微萃取气相色谱法间接测定水中三氯乙醛的方法。探讨了水中三氯乙醛萃取效率的影响因素,如温度、萃取时间和加盐量等,并确定萃取温度为40℃、萃取时间为5min和3g加盐量作为实验的优化条件。实验结果表明,在0.50-20.0μg/L范围内线性关系良好,方法检出限为0.08μg/L,实际水样加标回收率为103%-120%,测定结果的相对标准偏差不大于2.5%(n=5)。该方法操作简单,重现性好,可用于地表水中三氯乙醛的测定。  相似文献   

10.
动态液相微萃取-气相色谱法测定水样中有机磷农药残留   总被引:23,自引:0,他引:23  
金晓英  袁东星 《分析化学》2005,33(3):347-350
建立了水样中敌敌畏、二嗪农、毒死蜱、甲基对硫磷和对硫磷等5种有机磷农药的动态液相微萃取-气相色谱检测方法。实验表明甲苯是良好的萃取溶剂,甲苯体积为2μL时达到最佳萃取效果。液相微萃取是一种非平衡萃取过程,随着萃取次数的增加,萃取效率不断提高,本研究选择萃取次数为25次。在优化的实验条件下,各目标物的萃取富集倍数为21-60;回收率0.85%-2.38%之间;方法的检出限为0.1-0.3μg/L;基体加标检测的相对标准偏差(RSD)为4.9%-8.0%。本方法可用于水体中痕量有机磷农药的富集检测。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

15.
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   

16.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

19.
20.
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.  相似文献   

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