电感耦合等离子体发射光谱法测定地质样品中的钨、钼、锡

改进了电感耦合等离子体发射光谱法(ICP-AES)同时测定多金属矿石等地质勘查样品中钨、钼、锡的溶样方法。采取酸溶和碱熔结合,先用硝酸和高氯酸及氢氟酸溶样,用盐酸(1+1)浸取再过滤,滤渣及滤纸灰化后再碱熔,最后用电感耦合等离子体发射光谱法(ICP-AES)测定钨、钼、锡。克服了传统的酸溶法导致锡的测定结果偏低和碱熔法易堵塞ICP-AES矩管和雾化器的两大弊端,方法经国家一级标准物质验证,精密度和准确度均能达到日常分析的要求。     

Analysis of the fatty acid from Bupleurum Chinense DC in China by GC-MS and GC-FID

Fatty acid of the root of the medicinal plant of Bupleurum Chinense DC in China has been investigated by gas chromatography combined with mass spectroscopy. After methyl-esterification, eight fatty acid compositions were identified by GC-MS. A simple and rapid determination of the fatty acid has been firstly developed by GC-FID. The derivatization condition was investigated in order to validate this method. Palmitic acid, palmitoleic acid, oleic acid and linoleic acid were analyzed simultaneously by internal standard method. The validity of method has been examined both experimentally with good recovery, intra-assay precisions and linearity. The quick and accurate method of capillary gas chromatography could be used for the analysis of the fatty acid from Bupleurum Chinense DC.     

A rapid densitometric method for simultaneous quantification of gallic acid and ellagic acid in herbal raw materials using HPTLC

Gallic acid and ellagic acid are two widely occurring phenolic compounds of plant origin, to which many biological activities including anticancer and antiviral activity have been attributed. A simple HPTLC method has been developed for the simultaneous quantification of gallic acid and ellagic acid. The method was validated for precision, repeatability, and accuracy. Instrumental precision was found to be 0.083 and 0.78, and the repeatability of the method was found to be 1.07 and 1.50 (% CV) for gallic acid and ellagic acid, respectively. The accuracy of the method was checked by a recovery study conducted at two different levels and the average percentage recovery was found to be 101.02% for gallic acid and 102.42% for ellagic acid. The above method was used for the quantification of gallic acid and ellagic acid content in seeds of Abrus precatorius Linn., whole plant of Phyllanthus maderaspatensis Linn., and flowers of Nymphaea alba Linn. The proposed HPTLC method for the simultaneous quantification of gallic acid and ellagic acid was found to be simple, precise, specific, sensitive, and accurate and can be used for routine quality control of herbal raw materials and for the quantification of these compounds in plant materials.     

Spectrophotometric determination of ascorbic acid in pharmaceutical preparations and fruit juices

Conditions were established for the determination of ascorbic acid using phsophovanadotungstic acid as reagent. The method was applied to the determination of ascorbic acid in pure form, pharmaceutical preparations and fruit juices. The method is sensitive (2-24 micrograms ml-1 of ascorbic acid) and rapid and tolerates the presence of common ingredients usually found in fruit juices. The results obtained with the proposed method showed good agreement with those given by the standard method.     

Identification of novel circulating coffee metabolites in human plasma by liquid chromatography-mass spectrometry

This study reports a liquid chromatography-mass spectrometry method for the detection of polyphenol-derived metabolites in human plasma without enzymatic treatment after coffee consumption. Separation of available standards was achieved by reversed-phase ultra performance liquid chromatography and detection was performed by high resolution mass spectrometry in negative electrospray ionization mode. This analytical method was then applied for the identification and relative quantification of circulating coffee metabolites. A total of 34 coffee metabolites (mainly reduced, sulfated and methylated forms of caffeic acid, coumaric acid, caffeoylquinic acid and caffeoylquinic acid lactone) were identified based on mass accuracy (<4 ppm for most metabolites), specific fragmentation pattern and co-chromatography (when standard available). Among them, 19 circulating coffee metabolites were identified for the first time in human plasma such as feruloylquinic acid lactone, sulfated and glucuronidated forms of feruloylquinic acid lactone and sulfated forms of coumaric acid. Phenolic acid derivatives such as dihydroferulic acid, dihydroferulic acid 4'-O-sulfate, caffeic acid 3'-O-sulfate, dimethoxycinnamic acid, dihydrocaffeic acid and coumaric acid O-sulfate appeared to be the main metabolites circulating in human plasma after coffee consumption. The described method is a sensitive and reliable approach for the identification of coffee metabolites in biological fluids. In future, this analytical method will give more confidence in compound identification to provide a more comprehensive assessment of coffee polyphenol bioavailability studies in humans.     

Kinetic spectrophotometric determination of ascorbic acid by reduction of toluidine blue

A simple kinetic method is described for the determination of ascorbic acid. The procedure is based on the reduction of toluidine blue with ascorbic acid. The rate of reaction is followed by measuring the decrease in absorbance of toluidine blue (lambda(max) = 600 nm) as a result of its decolorization upon reduction by ascorbic acid. Ascorbic acid in the range of 3-35 microg/ml was determined using slope and fixed time methods of analysis, while the variable time method allowed the determination of 5-50 microg/ml of ascorbic acid. The percent relative standard deviation of the method varied from 0.78 to 1.32% depending on the kinetic method used. The high sensitivity of the method also allows determination of low levels of ascorbic acid in some fruits and vegetables such as dew melon, water melon, parsley and coriander.     

固相萃取-抑制电导离子色谱法测定水产品中有机酸

建立了梯度淋洗-抑制型电导离子色谱法检测水产品中有机酸的方法。在2～3个数量级范围内,该方法对目标化合物的检测线性良好。酒石酸的线性范围为15～500 ng/mL,检测限为0.05 mg/kg;柠檬酸线性范围为8～500 ng/mL,检测限为0.03 mg/kg。以大黄鱼、中华绒螯蟹、南美白对虾、文蛤为空白样品,加入酒石酸和柠檬酸质量分数分别为0.05,0.07和0.10 mg/kg,酒石酸的加标回收率介于84.4%～89.2%,RSD<6.5%,柠檬酸的加标回收率介于87.5%～93.8%,RSD<5.9%。     

导数光谱法测定歧化松香中树脂酸异构体

用紫外（UV）导数光谱法建立了同时测定歧化松香中五种树脂酸异构体的新方法。通过选择合适的求导阶数（n）、微分波长差（△λ）、扫描速度和定量方法,对不同批号的歧化松香中的主成分脱氢枞酸和微量组分枞酸、新枞酸、左旋海松酶及长叶松酸进行了测定（其中左旋海松酸和长叶松酸测定的是合量）,实验结果令人满意。该法可消除树脂酸各异构体及同系物的背景干扰,对迭加的树脂酸的检出和定量很有效。方法的平均回收率为99．0％,相对标准偏差小于0．2％。     

气相色谱质谱法测定植物油中脂肪酸

建立了气相色谱质谱法测定食用植物性油中脂肪酸检测的方法。植物油中的脂肪酸甘油酯在碱性条件下被水解为游离脂肪酸,随后采用三氟化硼将其转化为脂肪酸甲酯。采用同位素标记脂肪酸进行加标回收试验,回收率在94%以上。通过质谱的选择离子检测模式对硬脂酸、油酸、亚油酸等10种目标脂肪酸进行了检测,结果显示,该方法可用于油品的质量检测和日常分析。     

石榴籽中脂肪酸成分分析

采用两种方法对石榴籽中的脂肪酸进行了甲酯化,所得脂肪酸甲酯经GC-MS分析.方法一共检测出14种脂肪酸,主成分为油酸、亚油酸、山嵛酸、棕榈酸、硬脂酸和二十碳烯酸;方法二共检测出24种脂肪酸,主成分为棕榈酸、硬脂酸、花生酸、山嵛酸、油酸、亚油酸、二十碳烯酸等.其中的山嵛酸等多种饱和脂肪酸均为首次从石榴籽中鉴定出.     

核磁共振法测定松香中树脂酸总量及枞酸与脱氢枞酸含量

本文用吡嗪作分子间内标，利用氢核磁共振（＾１Ｈ－ＮＭＲ）积分法对松香中枞酸，脱氢枞酸及树脂酸总量进行了测定，并对该方法的可靠性进行了研究和比较，结果令人满意。该法不仅可以克服松香中各异物体及同系物的干扰，而且不必用极难制备和保存的天然纯纵酸和脱氢枞酸作标样。     

Photometric determination of alpha-ketoglutaric acid with diazotized sulphanilic acid

A new photometric method for the determination of alpha-ketoglutaric acid is presented. It is based on the colour reaction of alpha-ketoglutaric acid in sodium hydroxide solution with diazotized sulphanilic acid in the presence of sodium sulphite and sodium hypophosphite. This method is highly sensitive and fairly selective for alpha-ketoglutaric acid, and may be suitable for the determination of the acid in complex samples.     

High-performance liquid chromatographic determination of fatty acid binding proteins in rat liver with fluorescence detection.

A highly sensitive, simple and reproducible method for the quantitative determination of fatty acid binding protein in rat liver by post-column high-performance liquid chromatography with fluorescence detection is presented. Fatty acid binding protein in rat liver cytosols is separated by gel-permeation column chromatography, which is followed by fluorescence detection. The detection makes use of the fluorescence enhancement observed when a fluorescent fatty acid probe, dansylundecanoic acid, binds to fatty acid binding protein. The method is rapid, simple to perform and highly sensitive. The method was applied to the determination of fatty acid binding protein in liver from control and hypolipidaemic drug treated rats.     

基于生命周期评价技术研究全铁含量测定对环境的影响

利用生命周期评价软件Sima Pro7和环境影响评价模型IMPACT 2002+,通过对化学分析方法的清单分析及计算,评价和比较了3种测定铁矿中全铁含量的化学分析方法(酸溶法、碱熔法、微波消解法)对人类健康、生态质量、气候变化及资源消耗等的影响。发现3个方法对环境的影响主要集中于人类健康危害、气候变化和资源消耗方面。通过计算3种方法的生命周期单一环境负荷值,发现碱熔法、酸溶法和微波消解法的单一环境负荷值分别为1.97,1.81,0.07 m Pt,对环境总体的影响,碱熔法和酸溶法分别为微波消解法的28倍和26倍。单独对人类健康危害指标而言,碱熔法为1.15 m Pt,酸溶法为1.07 m Pt,微波消解法仅为0.039 6 m Pt。碱熔法、酸溶法和微波消解法的碳足迹分别为5.12,4.62,0.189 kg CO_2eq。说明微波消解法排放量最小,其环境友好性最佳,值得推荐。     

Improved high-performance liquid chromatographic method for simultaneous determination of 12 cytotoxic caged xanthones in gamboges, a potential anticancer resin from Garcinia hanburyi

The potential anti-tumor activity of gamboges, a herbal medicine derived from Garcinia hanburyi, has increasingly gained the interest of scientist worldwide. The major components of gamboges are cytotoxic caged xanthones. In the present study, an improved HPLC method was developed to simultaneously quantify 12 caged xanthones, including three pairs of epimers and four pairs of trans-cis isomers, i.e. forbesione, isomorellic acid, morellic acid, R-30-hydroxygambogic acid, S-30-hydroxygambogic acid, isogambogenic acid, gambogenic acid, gambogellic acid, R-isogambogic acid, S-isogambogic acid, R-gambogic acid and S-gambogic acid. This method was validated to be sensitive, precise and accurate with limits of detection of 0.03-0.08 microg/mL, overall intra-day and inter-day variations less than 7.9% and overall recovery over 93.2%. The correlation coefficients (r(2)) of the calibration curves were higher than 0.995 for all analytes. The newly established method was successfully applied to reveal the difference in the chemical profiles and contents of these analytes in gamboges from different origins. It can be concluded that this method was not only an effective quality control method to ensure the safety and efficacy consistency of gamboges, but also a useful tool for screening and determining more potent cytotoxic xanthones with potential anticancer activity.     

Simultaneous determination of ascorbic acid and acetylsalicylic acid in pharmaceutical formulations

A direct, simple, and practical first-derivative spectrophotometric method is described for simultaneous determination of ascorbic acid and acetylsalicylic acid. The effects of the solvent, excipients, and spectral variables on the analytical signal were investigated. The drugs were determined simultaneously with a 0.01 M methanolic hydrochloric acid solution as the solvent, and the signals were evaluated directly by using the zero-crossing method at 245.0 and 256.0 nm for acetylsalicylic acid and ascorbic acid, respectively. The method allows the simultaneous determinations of acetylsalicylic acid and ascorbic acid in the ranges of 6.6 x 10(-6) to 1.5 x 10(-4)M and 3.4 x 10(-6) to 2.0 x 10(-4)M, respectively, with standard deviation of <2.0%. The proposed method was applied to determinations of these drugs in tablets.     

The desalination of a mixed solution of an amino acid and an inorganic salt by means of electrodialysis with charge-mosaic membranes

A new electrodialysis with charge-mosaic membranes was proposed to achieve efficient desalination of a mixed solution of an amino acid and an inorganic salt. For such a mixed solution, the conventional electrodialytic desalination with both cation-and anion-exchange membranes had resulted in a considerable loss of the amino acid through the membranes. In this method, however, the amino acid in the desalination channel of the electrodialyzer migrates away from the membranes so that the permeation loss of the amino acid through the membrane can be prevented.

Batchwise desalination experiments by this method were carried out with a glutamic acid or arginine solution including NaCl under the condition of constant electric current density. Similar experiments by the conventional method were also carried out. As a result of comparing both methods, the amino acid loss in this method became much smaller than that in the conventional one. It was confirmed that this method was very useful for the desalination of an amino acid solution. The effects of operating conditions on the desalination process are also discussed.     

Determination of tannic acid and its phenolic metabolites in biological fluids by high-performance liquid chromatography.

A method for the identification and determination of tannic acid and its phenolic metabolites in biological fluids by high-performance liquid chromatography was developed. Tannic acid and four phenolic compounds, namely gallic acid, pyrogallol, 4-O-methylgallic acid and ellagic acid, were successfully extracted from the biological fluids by using ethyl acetate at acidic conditions. Gallic acid, pyrogallol and 4-O-methylgallic acid were found in the sheep urine, gallic acid, 4-O-methylgallic acid and ellagic acid in plasma, and gallic acid and ellagic acid in abomasal fluid after abomasal dosing of tannic acid. Tannic acid was found in the plasma apart from the abomasal fluid into which it was administered. The concentrations of tannic acid, gallic acid, pyrogallol, 4-O-methylgallic acid and ellagic acid in plasma, abomasal fluid and urine were measured. This method could be applied to measurement of other hydrolysable tannins and their phenolic metabolites in biological materials.     

氢化物发生-原子荧光光度法直接测定环境土壤中的痕量锗

试样采用硝酸+氢氟酸+高氯酸+磷酸分解至冒尽白烟,在磷酸介质中,不经分离富集,直接在原子荧光光度计上进行测定.方法简捷快速,成本低,结果经国家一级标准物质验证准确、可靠,适合于批量样品的分析测定.本法检出限为0.072 g/g,方法精密度(RSD%,n=8)为4.5%。     

Enhancing the sensitivity of spectrophotometric determination of formic acid with mercury(II) acetate

A precise spectrophotometric method was developed for determination of formic acid. The method surpasses in sensitivity the method based on proper UV absorption of formic acid.