RP-LC-UV Determination of Proanthocyanidins in Guazuma ulmifolia

A simple, reproducible, and efficient liquid chromatographic method was developed with UV detection. Water (0.05% TFA):acetonitrile (0.05% TFA) was used as the mobile phase in a gradient system for the determination of procyanidin B2 (PB2) and epicatechin (EC) in the bark of Guazuma ulmifolia Lam. The analysis was performed using a Phenomenex Gemini RP C₁₈ column (5 μm) as stationary phase, at 30 °C, with a flow rate of 0.8 mL min⁻¹, at a wavelength of 210 nm for detection and determination. The main validation parameters of the method were also determined. Calibration curves were found to be linear, with ranges of 20.00–150.00 (PB2) and 10.00–110.00 μg mL⁻¹ (EC). The correlation coefficients of linear regression analysis were between 0.9981 and 0.9988, and the detection limits were between 2.89 and 2.54 μg mL⁻¹. The contents of PB2 and EC were successfully determined, with satisfactory reproducibility and recovery. Recoveries of the PB2 and EC were 103.00 and 104.01%, respectively. The method was successfully applied to the determination of procyanidins in the bark of G. ulmifolia.

     

Proanthocyanidins ofPolygonum corarium. II

Eight proanthocyanidins have been isolated from the roots ofPolygonum coriarum. The structures of two dimers, two trimers, including an acylglycosylated one, a tetramer, and three oligomers have been determined. All the compounds isolated were polymers and copolymers of (-)epigallocatechin, (-)epigallocatechin gallate and (-)epicatechin with C-4C-8 interflavan bonds.Institute of the Chemistry of Plant Substances. Academy of Sciences of the Republic of Uzbekistan, Tashkent, Fax (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 233–244, March–April, 1994.     

Determination of organometallics in intra-oral air by LT-GC/ICP-MS

Low temperature gas chromatography (LT-GC) coupled on-line with inductively coupled plasma mass spectrometry (ICP-MS) has been used to identify volatile metal and metalloid compounds in human breath. After cryogenic sampling, the gas sample has been separated without any clean-up by increasing the temperature (–100 to +200° C). Simultaneous determination of 11 elements with ICP-MS was used for screening analysis. The detection limits of volatile compounds in intra-oral air are in the range of ng m^–3. Dimethyl selenium has been determined in each gas sample from six test persons in the range of 0.08 to 0.98 g m^–3.     

Determination of germanium by AAS in chloride-containing matrices

Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500°C resulting in an improved sensitivity. Germanium levels in zinc plant slag samples, have been determined and compared to those obtained for the same samples spiked with NaCl with platform and wall atomization using nickel perchlorate as a matrix modifier. The results were compared with those from a hydride generation system equipped with a liquid nitrogen trap. The recoveries for germanium have been almost complete and amount to 99% for the original slag samples and 80% for 15% (w/w) NaCl containing spiked samples.     

原子吸收光谱法测定莲子和莲子心中7种金属元素含量

利用火焰原子吸收光谱法测定6种不同产地的湘莲莲子和莲子心中7种金属元素含量. 莲子和莲子心样品经粉碎干燥后, 用硝酸-高氯酸混合液进行消解处理,采用火焰原子吸收光谱法测定样品中Cr、Cu、Zn、Fe、Mn、Pb、Cd的含量. 莲子和莲子心中富含微量元素Fe、Mn、Zn、Cu、Cr,有害金属元素Pb和Cd未检出. 各元素的加标回收率为98.58%~101.53%,RSD在0.78%~1.89%之间. 方法快速、简便、灵敏,结果准确可靠,为莲子和莲子心中金属元素含量测定提供了一种可靠的方法.     

Proanthocyanidins of Rhodiola semenovii

The structures of two compounds previously isolated fromRhodiola semenovii, rhodokhinoside (I) and rhodikhim (II), have been established.     

Proanthocyanidins of Rhodiola semenovii

The structures of two compounds previously isolated fromRhodiola semenovii, rhodokhinoside (I) and rhodikhim (II), have been established.Institute of the Chemistry of Plant Substances, Uzbek. Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 771–777, November–December, 1991.     

X射线荧光光谱法测定萤石中氟化钙

采用X射线荧光光谱仪可以快速准确测定萤石中总钙的含量.但测定其中氟化钙含量时,一方面,由于样品中碳酸钙计入钙量,从而造成氟化钙测定结果准确性较差.另一方面,铜、锌等金属元素在熔融制样时对铂金坩埚腐蚀较大,因此需要进行酸处理除去碳酸钙及铜、锌等金属元素.然而,样品经过酸处理后,质量会发生变化,造成熔剂与样品的比例不一致,从而影响测定结果.对样品前处理条件、XRF分析中熔片和仪器工作条件等进行了优化,建立了熔融制样、X射线荧光光谱法（XRF）准确测定萤石中氟化钙含量的方法.方法干扰少,具有良好的准确度和精密度,操作简单,提高了分析效率.     

Characterization of Natural and Alkaline-Oxidized Proanthocyanidins in Plant Extracts by Ultrahigh-Resolution UHPLC-MS/MS

In this study, we analyzed the proanthocyanidin (PA) composition of 55 plant extracts before and after alkaline oxidation by ultrahigh-resolution UHPLC-MS/MS. We characterized the natural PA structures in detail and studied the sophisticated changes in the modified PA structures and the typical patterns and models of reactions within different PA classes due to the oxidation. The natural PAs were A- and B-type PCs, PDs and PC/PD mixtures. In addition, we detected galloylated PAs. B-type PCs in different plant extracts were rather stable and showed no or minor modification due to the alkaline oxidation. For some samples, we detected the intramolecular reactions of PCs producing A-type ether linkages. A-type PCs were also rather stable with no or minor modification, but in some plants, the formation of additional ether linkages was detected. PAs containing PD units were more reactive. After alkaline oxidation, these PAs or their oxidation products were no longer detected by MS even though a different type and/or delayed PA hump was still detected by UV at 280 nm. Galloylated PAs were rather stable under alkaline oxidation if they were PC-based, but we detected the intramolecular conversion from B-type to A-type. Galloylated PDs were more reactive and reacted similarly to nongalloylated PDs.     

粉末X射线衍射法测定消咳宁片中碳酸钙含量

采用粉末X射线衍射法（PXRD）快速测定中成药消咳宁片中碳酸钙含量. 采用全谱拟合内标定量法,以ZnO为内标物,使用Cu Kα射线,电压为40 kV,电流为45 mA,扫描类型为Coupled Two Theta/Theta,扫描模式为Continuous PSD fast,衍射角（2θ）扫描范围8 °～40 °,步长0.02 °. 扫描获得PXRD图谱,通过全谱分析（TOPAS）软件进行内标定量分析得到碳酸钙的质量分数. 方法学验证结果,方法的平均加标回收率为98.9% [相对标准偏差（RSD）为1.0%,n=6],模拟样采用低中高三水平进行验证,测得回收率平均值为96.9%（RSD=1.0%,n=6）. 重复性测定RSD为1.2%（n=6）. X射线衍射法快速、灵敏、专属性强,全谱拟合内标定量法的准确度、重复性良好,可以解决消咳宁片中碳酸钙含量测定的难题.     

LC Determination of Gallic Acid in Preparations Derived from Schinus terebinthifolius Raddi

The aim of the present paper was to develop and validate a method to determine gallic acid and tannins by LC. Validation was carried out in accordance with Brazilian Resolution 899/2003. The method showed satisfactory results for precision, accuracy, specificity and linearity. Variations on the composition and flow rate of the mobile phase influenced the peak area and retention time. The method was applied to determine the amount of hydrolysable tannins in preparations containing Schinus terebinthifolius Raddi.     

Determination of volatile compounds in foliage of Fraser fir (Abies fraseri) and balsam fir (Abies balsamea)

The Fraser fir (Abies fraseri) and balsam fir (Abies balsamea) are eastern North American conifers which have been infested by an exotic insect, the balsam woolly adelgid (BWA). BWA infestation has had particularly severe effects on Fraser fir, with up to 95% mortality rates at some sites, and is characterized by attack on mature trees only. The purpose of this research was to perform a chemosystematic study to evaluate whether differences in volatile chemical concentrations of various stands of fir were observed as a function of resistance to BWA infestation. The concentrations of volatiles were determined by a methylene chloride extraction procedure, followed by analysis by gas chromatography. First, comparisons were made of concentration levels of volatiles in Fraser and balsam fir foliage of seedlings, saplings, and mature trees. If a chemical provided resistance, one would expect higher volatile levels in the balsam foliage because of its greater resistance to BWA. Second, the volatile levels in Fraser fir saplings and mature trees at uninfested sites were compared to the levels in surviving Fraser fir saplings and mature trees at infested sites. For a compound that provided BWA-resistance, higher volatile levels would be expected at the infested site because of the greater resistance of the surviving trees. Lastly, the concentrations of volatiles in sapling foliage were compared to those in mature foliage, where higher levels of resistance-providing chemicals would be expected in the saplings. 3-Carene was shown to consistently follow the expected pattern for a compound that provides resistance against BWA and β-pinene followed the pattern for the majority of the comparisons. These results indicate that while maltol and total volatiles did not correlate with the expected pattern, 3-carene, and possibly β-pinene and sesquiterpenes may provide fir with defense against BWA infestation.     

Proanthocyanidins of Polygonum coriarium. I

Six proanthocyanidins have been isolated from the roots ofPolygonium coriarium. The structures of three oligomeric proanthocyanidins have been established: taranin, consisting of [epigallocatechin gallate]-(48)-[epigallocatechin gallate]-(48)-[epigallocatechin-(48)-epigallocatechin₂-(48)-epigallocatechin; taranoside A - [epigallocatechin gallate]-7-0-[-(16)--D-Glcp]₃-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-gallocatechin; and taranoside B - [epigallocatechin gallate]-7-O-[-(16)--D-Glcp]₄-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-epigallocatechin-(48)-[epigallocatechin gallate).Institute of the Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–67, January–February, 1992