紫外可见分光光度法测定不同产地龙牙百合中皂苷含量

为建立龙牙百合总皂苷的测定方法,并确定不同产地龙牙百合中皂苷的含量,以便控制龙牙百合药材的质量,采用香草醛-高氯酸显色,在535 nm处,利用紫外可见分光光度法测定了10个批次的龙牙百合中总皂苷的含量.结果表明,10个不同产地龙牙百合中皂苷的含量,分别是:8.39%、8.11%、8.24%、7.62%、7.38%、9....     

Local and non-local sources of airborne particulate pollution at Beijing--The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside Beijing

A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles (TSP), 10%―70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%―86%) of the total mineral aerosols in TSP, 69% (52%―90%) in PM10, and 76% (59%―93%) in PM2.5 in spring, and 69% (52%―83%), 79% (52%―93%), and 45% (7%―79%) in TSP, PM10, and PM2.5, respectively, in winter, while only ～20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.     

Unmittelbare photometrische Bestimmung des Antimongehaltes von legierten St?hlen mit Jodid

Zusammenfassung Das photometrische Verfahren von Ploum [1,2] zur Antimonbestimmung mit Jodid in nichtlegierten Stählen wurde so modifiziert, daß einerseits die Arbeitszeit durch Vereinfachung der Methode herabgesetzt wird und es andererseits zur Untersuchung hochlegierter Stähle herangezogen werden kann. 20% Cr, 12% Ni, 3% Mo, 4% W, 2% Mn, 3% V, 1% Ti, 0,4% Si, 0,8% Nb, 0,04% Ta, 0,1% Co, 0,05% Al, 0,05% As, 0,014% Sn und 0,004% B haben keinen Einfluß. Cu > 0,2% stört. Es können Antimongehalte von 0,001–0,025% bestimmt werden.

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Direct photometric determination of antimony in alloy steels with iodide

The method of Ploum [1,2] for the direct determination of antimony in plain steels has been modified. It has been possible to reduce the working time in simplifying the method and to apply the procedure to the investigation of high-alloy steels. 20% Cr, 12% Ni, 3% Mo, 4% W, 2% Mn, 3% V, 1% Ti, 0.4% Si, 0.8% Nb, 0.04% Ta, 0.1% Co, 0.05% Al, 0.05% As, 0.014% Sn and 0.004% B have no effect. Cu >0.2% interferes. Sb contents from 0.001 to 0.025% can be determined.

     

ICP-AES法测定钢中的铈

建立了离子体发射光谱仪测定钢中铈元素的方法。为消除共存元素对铈分析游线的光谱干扰,选择Ce413．380nm作为分析线,铈含量在0．005％-0．50％之间工作曲线线性良好。对于含量范围在0．005％-0．10％的铈元素,回收率为85．6％-12．5％,测定结果的相对标准偏差小于9．74％（n=8）;对于含量范围在0．10％-0．50％的铈元素,回收率为99．5％-103．0％,测定结果的相对标准偏差小于3．52％（n=8）。该方法适宜钢中含量范围在O．005％-0．50％的铈元素的测定。     

电感耦合等离子体发射光谱法(ICP-AES)测定高铼酸钾中的19种杂质元素

建立了一种用稀盐酸溶解样品,标准工作溶液中匹配钾,ICP-AES测定高铼酸钾中19种杂质元素的方法。在选定的仪器工作条件下,样品加标回收率(%)分别为：钠94.4～101、钙98.8～102、铝98.1～102、镁95.8～99.1、钴98.4～101、钼97.3～103、钛97.6～102、钒96.6～106、锆96.2～97.7、铬97.8～101、铜98.1～108、铁92.9～104、锰95.5～98.4、镍93.6～101、钯93.3～101、铅96.5～103、锌95.2～103、铂95.9～99.9、铑94.5～96.3;方法精密度RSD%(n=7)分别为：钠2.0～5.5、镁1.1～3.5、铝0.9～2.5、钙1.5～7.3、钴1.1～3.1、钼0.9～4.5、钛1.0～2.8、钒1.6～4.0、锆1.4～3.6、铬0.77～4.6、铜0.74～1.8、铁1.3～3.8、锰1.1～2.0、镍0.99～5.0、钯1.1～2.4、铅1.3～9.1、锌0.80～6.7、铂1.2～10、铑0.78～8.6。方法简便、快速、准确, 满足生产分析要求。     

The role of the 1Bu state in carotenoid-to-bacteriochlorophyll singlet-energy transfer in the LH2 antenna complexes from Rhodobacter sphaeroides G1C, Rhodobacter sphaeroides 2.4.1, Rhodospirillum molischianum and Rhodopseudomonas acidophila

Subpicosecond time-resolved absorption spectra were recorded, in the visible and near-infrared regions, for the LH2 antenna complexes from Rhodobacter sphaeroides G1C, Rhodobacter sphaeroides 2.4.1, Rhodospirillum molischianum, and Rhodopseudomonas acidophila. The efficiencies of carotenoid-to-bacteriochlorophyll singlet-energy transfer through the 1¹B_u⁺, 1¹B_u⁻, and 2¹A_g⁻ channels in the LH2 complex were determined to be 48%, 19% and 22% in Rhodobacter sphaeroides G1C; 46%, 18% and 20% in Rhodobacter sphaeroides 2.4.1; 48%, 2% and 1% in Rhodospirillum molischianum; and 48%, 2%, 4% in Rhodopseudomonas acidophila. Sums of efficiencies through the three channels in the four LH2 complexes, 88%, 84%, 51% and 54%, nicely correlate with the efficiencies that were determined by comparison of the absorption and fluorescence-excitation spectra, 92%, 89%, 53% and 56%.     

苹果果实各部位菊酯类农药残留量分析

用正己烷-丙酮(体积比为1∶1)作提取剂,采用石英毛细管柱、电子捕获检测器,用气相色谱法测定苹果果皮、果肉、果核中甲氰菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯农药残留量.对苹果果肉试验结果表明,甲氰菊酯的回收率为80.9%～103.6%,相对标准偏差为1.30%～5.18%;氯氰菊酯的回收率为86.1%～103.9%,相对标...     

Multi-Year Study of the Chemical and Sensory Effects of Microwave-Assisted Extraction of Musts and Stems in Cabernet Sauvignon,Merlot and Syrah Wines from the Central Coast of California

Microwave technology (MW) was applied to musts and stems over three consecutive vintages in Cabernet Sauvignon, Merlot and Syrah wines from California (USA). Stems were added to musts at a rate of 50 and 100% (50% Stems and 100% Stems), either as untreated or after MW (50% MW Stems and 100% MW Stems). Stem additions lowered ethanol (up to 1.15% v/v reduction), but increased pH (up to 0.16 units) and the tannin content of the wines. In 2016, tannins increased by 103% (100% Stems), and 124% (100% MW Stems). In 2017, tannins increased by 39% in stem-added Merlot wines and by 63% (100% Stems) and 85% (100% MW Stems) in Syrah wines. In 2018, tannins in Syrah wines increased by 250% (100% MW Stems) and by 743% (100% Stems). Wines made with 50% Stems exhibited intermediate tannin contents. Must MW increased flavonols (up to 278% in Syrah wines), monoglucosylated, acylated and anthocyanin-derived pigments. Stem additions reduced wine color and polymeric pigment formation in Syrah. Must MW decreased the perception of coarseness and herbaceous flavors in Merlot, whereas stem additions increased herbaceous aromas in Syrah. Despite higher tannin contents in stem-added wines, no concomitant increases in astringency were observed.     

成都市东郊土壤中重金属元素垂直分布研究

采用王水消解样品,利用原子吸收分光光度法,对重金属元素(Cu、Pb、Zn、Cd)在成都市东郊土壤中的垂直分布进行了研究。该法对Cu的回收率为98%~104%,精密度为2.75%;Pb的回收率为95~97%,精密度为3.11%;Zn的回收率为99%~101%,精密度为2.31%;Cd的回收率为97%~102%,精密度为3.32%,测定方法简单、准确。     

ICP-AES法测定锌阳极中的铝、镉、铁、铜、铅

通过分析高频功率、雾化压力、辅助气流量和泵速等试验条件，建立了ICP-AES法测定锌阳极中铝、镉、铁、铜、铅的方法。用该方法测定锌阳极中的铝、镉、铁、铜、铅，其RSD分别为0.17%、0.63%、2.7%、5.2%、2.5%，回收率分别为99.3%-101.2%，99.3%-100.3%、97.1%-102.2%、97.8%-102.9%。对锌阳极试样进行测定，该方法的测定结果与GB4951-85方法的测定结果基本一致。     

Determination of boron in boron-alloyed steels by inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) procedure has been developed and examined for the determination of boron content (0.01 up to about 2% B) in boron-alloyed steels such as POLDI ATA BOR (65% Fe, 19%Cr, 12% Ni, 1.5% Mn, 1% B), POLDI ATA BOR EXTRA (62% Fe, 18% Cr, 13% Ni, 2.5% Mo, 1.5% Mn, 1% B) and POLDI ATA BOR-R (75% Fe, 18% Cr, 3.5% Ti, 1.8% B). The steel sample is dissolved with a mixture of hydrochloric, nitric, sulfuric and phosphoric acids in a quartz vessel. Borides of alloyed metals, especially of iron and chromium, are quantitatively decomposed. The presence of phosphoric acid in a sample solution reduces the volatility of boric acid with water vapour.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Determination of pesticide residues in nonfatty foods by supercritical fluid extraction and gas chromatography/mass spectrometry: collaborative study

A collaborative study was conducted to determine multiple pesticide residues in apple, green bean, and carrot by using supercritical fluid extraction (SFE) and gas chromatography/mass spectrometry (GC/MS). Seventeen laboratories from 7 countries participated in the final study, and a variety of different instruments was used by collaborators. The procedure simply entails 3 steps: (1) mix 1.1 g drying agent (Hydromatrix) per 1 g frozen precomminuted sample, and load 4-5.5 g of this mixture into a 7-10 mL extraction vessel; (2) perform SFE for 20-30 min with a 1-2 mL/min flow rate of carbon dioxide at 0.85 g/mL density (320 atm, 60 degrees C); and (3) inject the extract, which was collected on a solid-phase or in a liquid trap, into the gas chromatograph/mass spectrometer, using either an ion-trap instrument in full-scan mode or a quadrupole-type instrument in selected-ion monitoring mode. The ability of GC/MS to simultaneously quantitate and confirm the identity of the semivolatile analytes at trace concentrations is a strong feature of the approach. The selectivity of SFE and GC/MS avoids the need for post-extraction cleanup steps, and the conversion of the CO2 solvent to a gas after SFE eliminates the solvent evaporation step common in traditional methods. The approach has several advantages, but its main drawback is the lower recoveries for the most polar analytes, such as methamidophos and acephate, and the most nonpolar analytes, such as pyrethroids. Recoveries for most pesticides are >75%, and recoveries of nonpolar analytes are still >50%. The (within-laboratory) repeatability relative standard deviation (RSDr) values of the recoveries are generally <15%. More specifically, the average results from the 9-14 laboratories in the final analysis of 6 blind duplicates at 3 concentrations for each pesticide are as follows: carbofuran in apple (75-500 ng/g), 89% recovery, 7% RSDr, 9% reproducibility relative standard deviation (RSDR); diazinon in apple (60-400 ng/g), 83% recovery, 13% RSDr, 17% RSDR; vinclozolin in apple (6-400 ng/g), 97% recovery, 13% RSDr, 18% RSDR; chlorpyrifos in apple (50-300 ng/g), 105% recovery, 11% RSDr, 13% RSDR; endosulfan sulfate in apple (150-1000 ng/g), 95% recovery, 15% RSDr, 17% RSDR; trifluralin in green bean (30-200 ng/g), 58% recovery, 11% RSDr, 27% RSDR; dacthal in green bean (60-400 ng/g), 88% recovery, 11% RSDr, 17% RSDR; quintozene in green bean (60-400 ng/g), 79% recovery, 13% RSDr, 18% RSDR; chlorpyrifos in green bean (50-300 ng/g), 84% recovery, 11% RSDr, 17% RSDR; p,p'-DDE in green bean (45-300 ng/g), 64% recovery, 14% RSDr, 27% RSDR; atrazine in carrot (75-500 ng/g), 90% recovery, 11% RSDr, 15% RSDR; metalaxyl in carrot (75-500 ng/g), 89% recovery, 8% RSDr, 12% RSDR; parathion-methyl in carrot (75-500 ng/g), 84% recovery, 14% RSDr, 15% RSDR; chlorpyrifos in carrot (50-300 ng/g), 77% recovery, 13% RSDr, 19% RSDR; and bifenthrin in carrot (90-600 ng/g), 63% recovery, 12% RSDr, and 25% RSDR. All analytes except for the nonpolar compounds trifluralin, p,p'-DDE, and bifenthrin gave average Horwitz ratios of <1.0 when AOAC criteria were used. These 3 analytes had high RSDr values but lower RSDR values, which indicated that certain SFE instruments gave consistently lower recoveries for nonpolar compounds. The collaborative study results demonstrate that the method meets the purpose of many monitoring programs for pesticide residue analysis, and the Study Director recommends that it be adopted Official First Action.     

Photochemical stability of poly(vinyl alcohol) in the presence of collagen

The photochemical stability of poly(vinyl alcohol) (PVA) in the presence of 1%, 3% and 5% of collagen has been studied by Fourier Transform Infrared (FTIR) Spectroscopy, UV-vis spectroscopy, and Differential Scanning Calorimetry (DSC). PVA samples containing 1%, 3% and 5% of collagen were irradiated with UV light wavelength λ = 254 nm in air.The results have shown that PVA in the presence of 1%, 3% and 5% of collagen is less stable under UV radiation than pure PVA. A small amount of collagen in PVA enhances photooxidation in the PVA. The amount of crystallinity in PVA containing 1%, 3% and 5% of collagen decreases faster with UV irradiation time than that for pure PVA films.     

Chemical composition of the essential oil of Pelargonium quercetorum Agnew. of Iran

The volatile constituents in the essential oil of Pelargonium quercetorum Agnew., growing wild in Kurdistan, Iran were investigated through GC and GC/MS technique. Twenty-six compounds, representing 21 (80.77%) of the total oil were identified. The main components were: alpha-pinene (25.28%), alpha-fenchyl acetate (20.63%), limonene (9.94%), beta-caryophyllene (8.20%), camphene (4.31%), delta-cadinene (3.32%), beta-pinene (3.21%), alpha-amorphene (2.80%), valencene (2.73%), ledene (2.25%) and p-cymene (1.63%).     

Comparative study of volatile oil compositions of two Plectranthus species from northern India

The leaf and inflorescence essential oils of Plectranthus rugosus Wall. (syn. Rabdosia rugosa Wall.) and Plectranthus incanus L. (syn. Plectranthus mollis L.), which grow wild in Uttarakhand, India, were analysed and compared by capillary gas chromatography and gas chromatography-mass spectrometry. The analysis led to the identification of 43 constituents, forming 89.5-93.6% of the total oil compositions. Both leaf and inflorescence oil of P. rugosus were dominated by sesquiterpene hydrocarbons (71.8%, 71.7%) represented by β-caryophyllene (36.2%, 29.8%), germacrene D (25.2%, 28.2%) and α-humulene (6.6%, 8.6%) as the major constituents. Conversely, the leaf and inflorescence oil of P. incanus were dominated by monoterpenoids (74.4%, 65.8%) with piperitenone oxide (44.2%, 38.5%), piperitone (8.6%, 12.2%) and terpinolene (14.5%, 10.2%) as major constituents. Piperitenone oxide, piperitone, cis- and trans-piperitols and trans-piperitol acetate were the marker constituents in P. incanus, which were not noted in the essential oil of P. rugosus.     

电感耦合等离子体质谱法快速测定苦荞茶中铜、铅、镉、钴、镍

建立了用硝酸-高氯酸消解样品,电感耦合等离子体质谱法(ICP-MS)测定苦荞茶中铜、铅、镉、钴、镍的方法.方法具有灵敏度高、检出限低、精密度好、基体干扰少、准确可靠、快捷、简便的特点.各元素方法检出限(3SD,μg/L)分别为:铜0.009、铅0.023、镉0.015、钴0.022、镍0.035;方法精密度(RSD,n=12)分别为:铜2.5%～3.0%、铅2.1%～2.3%、镉3.0%～3.8%、钴2.5%～2.6%、镍1.5%～1.9%;各元素加标回收率分别为:铜95.0%～105.0%、铅95.0%～105.0%、镉98.0%～105.0%、钴95.0%～105.0%、镍95.0%～105.0%.在线用铑作为内标95.0%～105.0%.方法经国家一级标准物质验证,测定值与标准值吻合.应用于实际样品测定,结果满意.     

芹菜籽香气成分研究

采用固相微萃取法萃取黑龙江产芹菜籽香气成分,然后用GC—MS进行成分分析,并与水蒸气蒸馏法获得的精油成分进行比较．用CAR on PDMS萃取柱进行顶空固相微萃取时,共检测出26种成分,鉴定出占总成份89．650％的20种成分,主要成分为柠檬烯（35．980％）,β-月桂烯（20．500％）,β-蛇床烯（16．160％）,正戊基苯（5．295％）,β-蒎烯（3．412％）,α-蛇床烯（3．293％）．水蒸汽蒸馏法提取芹菜籽,以1．18％产率获得精油,共检测出23个成分,鉴定出占总精油91．375％的18种成分,主要成分为柠檬烯（31．149％）,β-蛇床烯（22．281％）,对甲苯基异戊酸酯（14．944％）,α-2-丙烯基苯甲醇（9．872％）,β-月桂烯（4．324％）和α-蛇床烯（4．322％）．     

烟煤和无烟煤中碘的赋存形态及其环境效应分析

采用逐级化学提取和电感耦合等离子体质谱(ICP-MS)研究烟煤和无烟煤中碘的赋存形态。结果表明,烟煤和无烟煤中各种形态的碘含量由高到低依次都是有机态、铁锰氧化物结合态、水溶态、残留态、离子交换态和碳酸盐结合态。烟煤和无烟煤中有机结合态碘平均含量分别为47.4%±3.28%和43.3%±2.42%,Fe-Mn氧化物结合态碘分别为36.8%±3.70%和34.6%±4.77%,水溶态和离子交换态碘平均含量之和分别为10.3%±3.00%和14.3%±3.37%,碘的平均潜在淋失率分别10.9%和16.0%,平均潜在可淋失浓度分别为0.9μg/g和1.2μg/g。这说明无烟煤中生物有效态碘含量高于烟煤,在表生条件下烟煤和无烟煤中淋出的碘都能导致地表水中碘的浓度升高;无烟煤中碘的有利环境效应大于烟煤,而不良环境效应小于烟煤。     

GC–MS analysis of phytoconstituents present in methanolic extract of Actinidia deliciosa L. fruits and its antioxidant activity

Kiwi fruit (KF) (Actinidia deliciosa L.) are members of the Actinidia genus (Family Actinidiaceae). Previously these plants have confirm anti-diabetic, anti-oxidant, anti-inflammatory, antifungal, anticarcinogenic, hepatoprotective, anti-microbial etc. properties. The therapeutic efficacy of complex phytoconstituents found in fruit extracts has piqued the interest of pharmaceutical companies and academics alike. Methanolic extract of kiwi fruit (MEKF) was analyzed by gas chromatography-mass spectroscopy and yielded positive results signaling towards identification and characterization of therapeutic claims of this species in the traditional system. The antioxidant activity of MEKF was determined by the most suitable DPPH method. The most significant constituents found in MEKF are 2-cyclohexylpiperidine (0.58%), phenol, 2,4-bis(1,1-dimethylethyl)- (0.13%), 1,6-anhydro- β-d-glucopyranose (0.52%), dodecanoic acid (0.32%), 2-heptenoic acid, trimethylsilyl ester (2.84%), Tetradecanoic acid (1.87%), Neophytadiene (2.81%), Hexahydro farnesyl acetone (1.72%), Neophytadiene (0.97%), n-hexadecanoic acid (19.00%), Ethyl hexadecanoate (7.21%), Linoleic acid ethyl ester (0.23%), Phytol (4.74%), α-linolenic acid (16.73%), Ethyl (9z,12z)-9,12-octadecadienoate (2.92%), Octadecanoic acid (4.76%), Octadecanoic acid, 17-methyl-, methyl ester (1.68%), Phytol, acetate (0.15%), 2-Methylhexacosane (0.97%), Ethyl 9,12,15-octadecatrienoate (0.81%), Tetracontane (1.45%), α-tocospiro A (0.15%), α-tocospiro B (0.19%), 3.β-Acetoxystigmasta-4,6,22-triene (0.24%), Octacosane, 1-iodo (0.43%), 4,6-cholestadien-3.β-ol, benzoate (2.14%), γ.-Sitosterol (4.40%), and Tigogenin (2.32%). The found results in the analysis of the antioxidant activity of MEKF showed significant free radical scavenging capacity against DPPH-generated free radicals due to the presence of alkaloids, glycoside, terpenoids, vitamins, and some other reported compounds. In the pharmaceutical industry, GC-MS reports will be useful for identifying a wide range of phytoconstituents in polyherbal extracts and standardizing of plant materials.     

液相色谱-串联质谱法测定蔬菜和水果中硝苯菌酯的残留量

建立了一种通过检测硝苯菌酯(2,4-dinitro-6-(1-methylheptyl) phenyl crotonate, 2,4-DNOPC)相应的水解产物2,4-二硝基-6-(1-甲基庚基)苯酚(2,4-dinitro-6-(1-methylheptyl) phenol, 2,4-DNOP)来测定蔬菜和水果中2,4-DNOPC残留量的液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)检测方法。蔬菜和水果样品用丙酮-甲醇-盐酸的混合液进行液-液分配提取,在碱性条件下超声水解后再进行液-液分配提取,然后进行LC-MS/MS测定。2,4-DNOPC在6种蔬菜和水果中的回收率试验结果表明,2,4-DNOPC在甘蓝中的添加回收率为89.7%～93.3%,相对标准偏差(RSD)为6.3%～8.5%;在黄瓜中的添加回收率为87.7%～95.1%, RSD为5.8%～10.4%;在番茄中的添加回收率为89.3%～96.0%, RSD为6.8%～9.2%;在苹果中的添加回收率为92.0%～98.3%, RSD为5.1%～10.3%;在梨中的添加回收率为89.0%～95.0%, RSD为5.3%～10.2%;在葡萄中的添加回收率为81.2%～95.8%, RSD为5.8%～10.4%。2,4-DNOPC在6种蔬菜和水果的最低检测浓度均为0.01 mg/kg。该检测方法样品前处理简单、快速,分析时间短,灵敏度、准确度和精密度均符合农药残留检测要求,适用于蔬菜和水果中硝苯菌酯残留量的检测。