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1.
在一定条件下,PO43-与Mo(VI)形成的磷钼杂多酸H3[P(Mo3Ol0)4]被维生素C还原成磷钼蓝,其最大吸收波长为710 nm,磷钼蓝的表观摩尔吸光系数为4.8×103L/(mol.cm),维生素C在1.0~80.0μg/mL浓度范围内符合比尔定律,线性回归方程为A=-0.01747+0.02722ρ(μg/mL),相关系数为0.9992,检测限为0.23μg/mL。该方法已用于水果中维生素C含量的测定。  相似文献   

2.
丝瓜中维生素C含量的测定   总被引:1,自引:0,他引:1  
为建立丝瓜中维生素C含量直接测定的新方法,以10%盐酸溶液为溶剂,采用紫外分光光度法测定其含量。结果表明,维生素C在0~10 mg/L质量浓度范围内与吸光度呈良好的线性关系,回归方程为:y=0.047 46ρ+0.001 09,r=0.999 7。检出限为0.023μg/mL,加标回收率在90.6%~99.0%之间。该法操作简单,结果准确,应用于维生素C含量的测定,结果准确,令人满意,可作为控制维生素C质量的方法。  相似文献   

3.
分光光度法测定新鲜蔬菜中维生素C的含量   总被引:2,自引:0,他引:2  
水溶性的维生素C是一种人体必需的营养物质。维生素C是含有烯二醇基的多羟基内酯结构,利用其水溶液在波长265nm处有较强烈的紫外吸收峰,建立了直接用紫外分光光度法测定新鲜蔬菜中维生素C含量的方法。实验结果表明,维生素C的含量在1.0~12.0μg/mL内线性关系良好,线性方程为A=0.066 03c+0.019 74(R2=0.997 51),检出限为0.044μg/mL,样品加标回收率为97.5%~105.4%。方法操作简单,准确度高,对新鲜蔬菜的测定结果令人满意。  相似文献   

4.
建立高效液相色谱法同时测定谷瑞德胶囊中谷胱甘肽及维生素C含量的方法。色谱柱为InertSustain C_(18)柱(250 mm×4.6 mm,5μm);以0.025 mol/L磷酸二氢钠溶液(用磷酸调pH 3.0)为流动相;检测波长为220 nm。结果表明,谷胱甘肽与维生素C的质量浓度分别在65.592~1 311.84,20.632~412.64μg/mL范围内与色谱峰面积呈良好的线性关系,线性相关系数均为1,检出限分别为16,177 ng/mL。谷胱甘肽与维生素C的加标回收率分别为97.1%~99.1%,98.2%~100.6%,测定结果的相对标准偏差分别为0.66%,0.87%(n=6)。该方法灵敏度高、重现性好,稳定可控,可为谷瑞德胶囊质量标准的建立提供技术支持。  相似文献   

5.
基于卡那霉素对CdTe量子点荧光的增强效应,建立一种直接测定尿液中卡那霉素含量的同步荧光光谱法。研究发现采用同步荧光光谱法,能够有效避免尿液中复杂基质的荧光干扰。在优化实验条件下,卡那霉素浓度在0.2~20.0μg/mL范围内与体系相对同步荧光强度呈良好的线性关系,相关系数为0.9996,检出限为0.005μg/mL。该方法用于尿液样品中卡那霉素含量的直接测定,回收率为96.3%~104.4%。  相似文献   

6.
采用荧光光谱法研究了诺氟沙星与碘形成荷移络合物的荧光性质,发现碘对诺氟沙星有强烈的荧光增敏效应。据此,建立了一种高灵敏的测定诺氟沙星的荷移荧光光谱新方法。优化了影响反应的不同变量和参数,在最佳实验条件下,方法线性范围为0.04~1.5μg/mL,检出限为0.01μg/mL。该方法用于药物制剂中诺氟沙星含量的测定,其回收率为98.09%~99.97%。  相似文献   

7.
在中性或弱酸性中,氨存在条件下亚硫酸盐与邻苯二甲醛生成强荧光物质,而过氧化苯甲酰对该荧光物质具有抑制作用。基于该原理建立了一种简单、灵敏测定面粉中微量过氧化苯甲酰的荧光光度法。荧光物质的最大激发波长和发射波长分别为326、389 nm。方法检出限为0.23μg/mL,线性范围为0.8~8.0μg/mL,线性回归方程为ΔF=20.589c 2.8805,相关系数r=0.999 0。该法用于测定面粉中微量过氧化苯甲酰含量的相对标准偏差为1.34%~2.32%,回收率为95.4%~101.1%。  相似文献   

8.
绿原酸的直接荧光分析法及其抗氧化性研究   总被引:2,自引:0,他引:2  
绿原酸水溶液能产生微弱荧光,当加入95%的乙醇后,其荧光强度大大增强,基于此,建立了直接测定绿原酸的荧光分析新方法.pH=1.72时,在1.416~14.16μg/mL浓度范围内,绿原酸的荧光强度与其浓度呈良好的线性关系,相关系数r为0.9963;检出限为0.081 μg/mL;相对标准偏差为0.54%.该方法灵敏度高...  相似文献   

9.
为建立催化动力学荧光法测定痕量甲醛的新方法,基于在酸性介质中,甲醛催化KBrO3氧化藏红T的褪色反应,使其荧光猝灭的原理,将反应体系在沸水浴中加热8 min,流水冷却3min,采用动力学荧光法测定痕量甲醛。结果表明,甲醛在0.02~0.14μg/mL范围内与△F值呈良好的线性关系,线性方程为△F=-1.642 8+274.12C(μg/mL),r=0.996 9,检出限为0.011μg/mL。该法简便,快速,常见共存物质干扰小,可用于水发食品及其它食品中甲醛含量的测定,加标回收率为84.63%~94.93%。  相似文献   

10.
建立高效液相色谱法测定桂利嗪原料中4种有关物质的方法。采用Thermo Hypersil C18(100 mm×4.0mm,3μm)色谱柱,以10 g/L乙酸铵溶液-0.1%冰乙酸乙腈溶液为流动相进行梯度洗脱,流量为1.5 mL/min,检测波长为230 nm,柱温为30℃,进样体积为10μL。桂利嗪的质量浓度线性范围为1.25~125μg/mL,相关系数为0.999 9,4种杂质的质量浓度线性范围为1.25~125μg/mL,相关系数为0.999 7~0.999 9。桂利嗪检出限为0.2μg/mL,杂质A检出限为0.1μg/mL,杂质B、杂质C、杂质D检出限均为0.25μg/mL。杂质A、杂质B、杂质C、杂质D测定结果的相对标准偏差分别为3.4%、2.4%、2.8%、1.8%,平均加标回收率分别为103.4%、100.4%、101.1%、101.3%。该方法专属性强,重复性好,可有效控制桂利嗪原料的质量,保证已知杂质的有效检出。  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.
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   

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.
18.
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   

19.
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   

20.
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   

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