流动注射法同时测定海水中氨氮和磷酸盐

采用流动注射法同时测定海水中氨氮和磷酸盐的含量。在优化的试验条件下,氨氮和磷酸盐的线性范围分别为0.25 mg·L-1和0.30 mg·L-1以内,检出限(3S/N)分别为0.42μg·L-1和0.56μg·L-1。氨氮和磷酸盐加标回收率分别在85.0%~103%和86.7%~103%之间,测定值的相对标准偏差(n=6)分别在0.43%~5.3%和0~4.1%之间。方法用于分析标准物质,测定结果与分光光度法的结果一致。     

连续流动注射法测定土壤和植物中全磷

应用AA3型连续流动分析仪测定了土壤和植物中全磷.结果表明:对于采用高氯酸-硫酸消解的土壤样品以及硫酸-过氧化氢消解的植物样品,在测定时调节反应混合液的酸度使其在显色的适宜范围内,磷的质量浓度在6 mg·L-1(土壤)和7.5 mg·L-1(植物)以内呈线性,相关系数分别为0.999 2(土壤)和0.999 6(植物);加标回收率98.5%～100.5%,相对标准偏差小于2%,检出限分别为0.010 mg·L-1(土壤)和0.013 mg·L-1(植物).     

纳氏试剂分光光度法测定土壤中全氮含量

提出了纳氏试剂分光光度法测定土壤中全氮含量。以硫酸铜为加速剂,用硫酸对土壤样品进行消解。消解完毕的溶液用400g·L-1氢氧化钠溶液调节其酸度至pH 10左右,溶液与沉淀一起移入容量瓶中,定容至200mL。移取上清液10mL于50mL比色管中,加入酒石酸钾钠溶液作掩蔽剂,加入纳氏试剂显色后,加水定容,于波长420nm处测量其吸光度并计算土壤样品中全氮含量。氮的质量浓度在2mg·L-1以内与吸光度呈线性关系。方法用于土壤样品分析,测定值与滴定法测定值相符,测定值的相对标准偏差(n=10)为0.24%;回收率在92.3%~112%之间。     

共振散射光谱法测定卡波姆

基于卡波姆在强酸性介质中产生自聚集作用导致其共振散射光显著增强,建立了测定卡波姆的共振散射光谱法。在优化的试验条件下,卡波姆940,971P,974P质量浓度的线性范围分别为20~120mg·L-1,50~300 mg·L-1,20~300 mg·L-1,检出限(3σ)分别为0.2,0.03,0.14μg·L-1。方法用于样品分析,加标回收率在96.9%~100%之间,测定值的相对标准偏差(n=6)在1.2%~2.3%之间。     

人工神经网络光致发光法同时测定α-萘乙酸和吲哚-3-乙酸

研究了酸度、有机溶剂、重原子效应和共存物对α-萘乙酸(NAA)及吲哚-3-乙酸(IAA)光致发光性质的影响,建立了人工神经网络不经分离同时测定NAA和IAA的新方法。该法测定NAA和IAA的线性范围分别是0.012~0.24 mg.L-1和0.0034~0.068 mg.L-1(荧光)0、.18~1.8 mg.L-1和0.18~1.8 mg.L-1(燐光),检出限分别为0.0039 mg.L-1和0.0019 mg.L-1(荧光)0、.14 mg.L-1和0.13 mg.L-1(燐光)。方法用于合成样和水样测定,回收率在93%~109%之间,结果满意。     

微波消解样品-火焰原子吸收光谱法测定美白化妆品中铅和铜

乳液和水类美白化妆品经硝酸-过氧化氢混合液消解,粉类美白化妆品经硝酸-过氧化氢-氢氟酸混合液消解,用火焰原子吸收光谱法测定样品中铅和铜的含量。在优化的仪器工作条件下,铅和铜的质量浓度分别在9.0 mg·L-1和11.0 mg·L-1以内与其吸光度呈线性关系,检出限(3s)分别为21.8μg·L-1和16.2μg·L-1。方法用于美白化妆品中铅、铜的测定,测得回收率分别在98.0%~102.5%和96.7%~105.0%之间。     

气相色谱-质谱法测定酒中16种邻苯二甲酸酯

应用气相色谱-质谱法测定酒中16种邻苯二甲酸酯的含量。样品经乙酸乙酯提取,所得提取液用DB-5MS UI色谱柱分离,在全扫描/选择离子监测共用模式下测定。16种邻苯二甲酸酯的质量浓度均在0.5~10.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.01~0.10mg·L-1之间。日间加标回收率在83.7%~114%之间,日间相对标准偏差(n=6)在3.4%~9.8%之间;日内加标回收率在81.9%~113%之间,日内相对标准偏差(n=6)在1.5%~6.7%之间。     

气相色谱法同时测定乙烯-丙烯酸甲酯共聚物的降解产物丙烯酸甲酯及甲醇

提出了气相色谱法测定乙烯-丙烯酸甲酯(EMA)共聚物降解产物丙烯酸甲酯和甲醇的含量。样品经水浸取,浸取液于气相色谱分析,用火焰离子化检测器测定,外标法定量。丙烯酸甲酯和甲醇的质量浓度分别在0.1~2.0和1.0~20.0 mg.L-1范围内与其峰面积呈线性关系,检出限(3S/N)分别为0.02,0.2 mg.L-1。丙烯酸甲酯和甲醇的回收率分别在96.2%~100.5%和94.6%~97.4%之间,测定结果的相对标准偏差(n=6)均小于6.5%。     

电感耦合等离子体原子发射光谱法测定铌精矿中铌、锰、钛

采用电感耦合等离子体原子发射光谱法测定铌精矿中铌、锰、钛的含量。选择铌、锰、钛的分析谱线分别为309.418,257.610,334.940nm。铌、锰、钛的线性范围在1.00~10.00mg·L-1之间,方法的检出限(3s)在0.010~0.015mg·L-1之间。方法用于标准样品B-K1的分析,测定值与认定值一致。加标回收率在94.5%~103%之间,测定值的相对标准偏差(n=11)在1.4%~2.7%之间。     

气相色谱-质谱法测定大鼠血浆中尼古丁及其药物代谢动力学研究

采用气相色谱-质谱法测定大鼠血浆中的尼古丁。血浆样品采用蛋白沉淀法净化,采用DB-Wax毛细管色谱柱分离,质谱中选择电子轰击离子源和选择离子监测模式,以茴香脑为内标进行定量。并采用PKSlover 2.0软件计算药代动力学参数。尼古丁的线性范围为0.10~2.0mg·L-1,检出限为4.59μg·L-1。对空白样品进行加标回收试验,回收率在85.0%~90.1%之间,相对标准偏差(n=6)小于3.0%。应用此方法考察了灌胃给药的大鼠血浆样品中尼古丁代谢动力学特点,主要动力学参数AUC0-t,AUC0-∞,Tmax和ρmax分别为8.570mg·L-1·h-1,10.49mg·L-1·h-1,1.0h,998.9μg·L-1,结果呈现药物代谢动力学过程。     

Total synthesis of janadolide

The first total synthesis of janadolide, a new cyclic polyketide-peptide hybrid possessing a tert-butyl group, is described. The synthesis of an unsaturated hydroxycarboxylic acid was effected via the lithiation of vinyl iodide followed by addition to a Weinreb amide with a tert-butyl group and stereoselective 1,2-reduction. The cyclic structure was constructed by macrolactamization at the amide bond between the proline moiety and fatty acid moiety.     

Total synthesis of glypetelotine

A total synthesis of glypetelotine, the first sulphur-containing indole alkaloid from the leaf extracts of Glycosmis petelotii collected in the north of Vietnam, was described from indole through 6 steps. The structure of the glypetelotine was confirmed by IR, 1H NMR, 13C NMR and MS analysis. The spectral data of synthetic compound was identical with those of natural compound.     

Corylifolin 的首次全合成

类异戊二烯酚类化合物 Corylifolin(1) 是由 Snapka 等[1]于1998年从豆科植物 Psoralea Corylifolia 中分离得到的天然产物, 其结构已由波谱学和化学方法确定, 一同分离的还有化合物 Bakuchio(2). 植物 Psoralea Corylifolia 是广泛分布于中国和印度的豆科类植物, 药理实验研究表明, 此植物对 Streptococcus 和 Paramecium 等具有很高的活性, 因此它作为民间药材被长期使用. 化合物 Corylifolin(1) 和 Bakuchio(2) 具有类似的化学结构及生物活性, 是有效的DNA复制聚合酶的抑制剂, 而且具有抗肿瘤和抗诱变作用.     

Total synthesis of beauveriolide I

The first total synthesis of beauveriolide I (1a), a selective ACAT inhibitor, is described. The key steps in this synthesis involved a diastereoselective aldol condensation sequence and a macrocyclization.     

水中总磷和总氮含量的离子色谱测定法

采用紫外光-臭氧氧化结合离子色谱法对氧化消解后的水样同时进行总磷和总氮的测定。配制Na2CO3/NaHCO3淋洗液,采用1 mL定量环,大体积直接进样。在优化工作条件下,总磷在0.05～5.00 mg/L,总氮在0.10～10.0 mg/L范围内线性良好,线性相关系数分别为0.9999和0.9998,总磷和总氮检出限为分别3.60和4.57μg/L;总磷和总氮的检测相对标准偏差(RSD)分别低于4.9%和4.1%,总磷加标回收率为95.0%～105.0%,总氮加标回收率为93.0%～103.0%。自然环境水样检测与真实值相对偏差小于4.2%。本方法选择性好,灵敏度高,精密度和准确度高,用于实际水样中总磷和总氮含量测定的结果与国标法(GB11894-89,GB11893-89)基本一致     

First Total Synthesis of 6-Oxodendrolasinolide

~~First Total Synthesis of 6-Oxodendrolasinolide1.For a report on vinyl dithiane regioselectivity and similar reactions, see: (a) W. S. Murphy, S. Wattanasin, J. Chem. Soc, Perkin Trans. 1, 1980, 2678. (b) L. Colombo, C. Gennari, M. Santandrea, et al, J. …     

Total synthesis of Punicagranine

This communication details the first total synthesis of Punicagranine, a new pyrrolizine alkaloid isolated from the peels of the pomengranate, Punica granatum, the basis for traditional Chinese medicine, with anti-inflammatory activity. Two concise, 4–5 step routes were developed to rapidly prepare Punicagranine in 10.7–12.1% overall yields. One route features an intramolecular Heck reaction, while the other relies on a 1,3-dipolar cycloaddition. The latter route proceeds on scale to support future biological studies.     

Total synthesis of xanthanolides

The total synthesis and determination of the absolute configuration of (+)- and (−)-sundiversifolide have been achieved via intramolecular acylation and Wittig-lactonization as the key steps. The xanthanolide sesquiterpene lactones, 8-epi-xanthatin (1), dihydroxanthatin (2), and xanthatin (3) were also prepared, starting from a common intermediate derived from the synthesis of sundiversifolide.     

Total synthesis of myceliothermophins A-E

Total synthesis of an antitumor compound myceliothermophin A and related compounds based on a convergent synthetic strategy was investigated. A common decalin skeleton of myceliothermophins was stereoselectively constructed by an IMDA reaction. The fully elaborated precursor of myceliothermophins was obtained via aldol reaction of N-protected γ-methoxylactam with decalin aldehyde. By using Teoc group for the protection of nitrogen atom of lactam ring, selective deprotection prior to the hydrolysis of methoxyaminal moiety was successfully achieved to obtain γ-methoxylactams (myceliothermophins C and D). Subsequent hydrolysis of these compounds afforded the corresponding γ-hydroxylactam, and myceliothermophins A and B in high yield. Myceliothermophin E was also synthesized by dehydration of the obtained γ-hydroxylactams. The absolute configurations of myceliothermophins A-E were also successfully determined.     

Total synthesis of pyripyropene A

The total synthesis of pyripyropene A, a potent ACAT2 inhibitor with high isozyme selectivity, was completed. Key features of the synthetic strategy include Ti(III)-mediated radical cyclization and Peterson olefination for the construction of the AB ring segment and stereoselective dihydro-γ-pyrone formation (C-ring). The total synthesis provided pyripyropene A in 5.3% overall yield over 17 steps.