X-ray fluorescence analysis of rare earth elements in rocks using low dilution glass beads.

Major and trace elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Gd, Dy, Th and U) in igneous rocks were assayed with fused lithium borate glass beads using X-ray fluorescence spectrometry. Low dilution glass beads, which had a 1:1 sample-to-flux ratio, were prepared for determination of rare earth elements. Complete vitrification of 1:1 mixture required heating twice at 1200 degrees C with agitation. Extra pure reagents containing determinants were used for calibrating standards instead of the rock standard. The calibration curves of the 23 elements showed good linearity. Furthermore, the lower limits of detection corresponding to three times the standard deviation for blank measurements were 26 mass ppm for Na2O, 6.7 for MgO, 4.5 for Al2O3, 4.5 for SiO2, 18 for P2O5, 1.1 for K2O, 4.0 for CaO, 3.9 for TiO2, 1.6 for MnO, 0.8 for Fe2O3, 0.5 for Rb, 0.2 for Sr, 0.4 for Y, 0.5 for Zr, 3.3 for La, 6.5 for Ce, 2.7 for Pr, 2.1 for Nd, 1.7 for Sm, 0.7 for Gd, 2.7 for Dy, 0.5 for Th, and 0.6 for U. Using the present method, we determined the contents of these 23 elements in four rhyolitic and granitic rocks from Japan.     

Concentrations of 239,240Pu and 241Am of marine products in coastal waters of Ibaraki

More than 200 samples of marine products have been collected and analyzed for plutonium and almost 100 samples for americium around Hitachi, Tokai and Oarai in the pacific coast of Ibaraki prefecture. The data have shown that the concentration factor (CF) values for plutonium were 330 for bivalve, 770 for abalone (muscle) and 610 for brown algae. For americium, the CF was calculated as 2400 for bivalve, 1000 for abalone (muscle) and 420 for brown algae.     

Quantitative determination of aflatoxin B1-oxime by column liquid chromatography with ultraviolet detection.

Liquid chromatography was used for the quantification of aflatoxin B1-oxime (AFB1-oxime). The yield of AFB1-oxime in the reaction mixture was 89%, while after purification on silica gel it was 72%. LC analysis of the reaction mixture after silica gel fractionation revealed a retention time of 0.84 min for AFB1-oxime, 8.42 min for AFB1, 1.21 min for unknown 1 and 1.61 min for unknown 2. UV-visible analysis of the reaction mixture after silica gel fractionation showed a lambda(max) of 269 and 361 nm for AFB1-oxime, 263 and 360 nm for AFB1, 273 nm for unknown 1 and 275 nm for unknown 2. Excitation and emission wavelengths were found to be 269 and 368/438 nm for AFB1-oxime, 359/424 nm for AFB1, 270 and 367/450 nm for unknown 1 and 273 and 416/447 nm for unknown 2. The method may find versatile application in monitoring reactions for the preparation of oximes of various analytes for the synthesis of their immunogens.     

Simultaneous determination of major,minor and trace elements in biocarbonates by inductively coupled plasma mass spectrometry

A method was developed for simultaneous determination of major (Ca), minor (Mg and Sr) and trace (Ba and U) elements in biocarbonates by inductively coupled plasma mass spectrometry (ICP-MS). The method precision (RSD%) is 0.73% for Ca, 0.77% for Mg, 0.59% for Sr, 2.02% for Ba, 1.13% for U, 0.67% for Mg/Ca, 0.27% for Sr/Ca, 2.06% for Ba/Ca and 1.23% for U/Ca. The ratio precision suggests that ICP-MS is satisfactory for obtaining multi-ratio data from biocarbonates. This technique was applied to 67 continuous coral samples.     

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.     

加速溶剂萃取-气相色谱-串联质谱法测定茶叶中10种吡唑和吡咯类农药的残留量

建立了加速溶剂萃取(ASE)-气相色谱-串联质谱(GC-MS/MS)法用于测定茶叶中10种吡唑和吡咯类农药残留。ASE萃取压力为1.03×107 Pa,萃取温度为100 ℃,萃取时间为5 min,萃取溶剂为乙酸乙酯-正己烷(1:1, v/v)。萃取循环1次,萃取液浓缩后用Envi-Carb/PSA固相萃取小柱净化,乙酸乙酯-正己烷(1:1, v/v)洗脱。洗脱液浓缩后,用正己烷定容,供GC-MS/MS测定,外标法定量。方法的准确度和精密度均符合残留分析要求。方法的定量限(LOQ)分别为唑螨酯0.003 mg/kg、氟虫腈硫化物0.001 mg/kg、氟虫腈0.002 mg/kg、氟虫腈砜化物0.005 mg/kg、溴虫腈0.002 mg/kg、氟硅唑0.006 mg/kg、野燕枯0.001 mg/kg、吡草醚0.001 mg/kg、吡螨胺0.0003 mg/kg、唑虫酰胺0.005 mg/kg。方法的灵敏度能满足各国有关农药的残留限量要求。     

Determination of low-level agricultural residues in soft drinks and sports drinks by liquid chromatography/tandem mass spectrometry: single-laboratory validation

In this study, sponsored by PepsiCo Inc., a method was validated for measurement of 11 pesticide residues in soft drinks and sports drinks. The pesticide residues determined in this validation were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, paraoxon-methyl, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D) when spiked at 0.100 microg/L (1.00 microg/L for phorate). Samples were filtered (if particulate matter was present), degassed (if carbonated), and analyzed using liquid chromatography with tandem mass spectrometry. Quantitation was performed with matrix-matched external standard calibration solutions. The standard curve range for this assay was 0.0750 to 10.0 microg/L. The calibration curves for all agricultural residues had coefficient of determination (r2) values greater than or equal to 0.9900 with the exception of 2 values that were 0.9285 and 0.8514. Fortification spikes at 0.100 microg/L (1.00 microg/L for phorate) over the course of 2 days (n=8 each day) for 3 matrixes (7UP, Gatorade, and Diet Pepsi) yielded average percent recoveries (and percent relative standard deviations) as follows (n=48): 94.4 (15.2) for alachlor, 98.2 (13.5) for atrazine, 83.1 (41.6) for butachlor, 89.6 (24.5) for isoproturon, 87.9 (24.4) for malaoxon, 96.1 (9.26) for monocrotophos, 101 (25.7) for paraoxon-methyl, 86.6 (20.4) for phorate, 101 (16.5) for phorate sulfone, 93.6 (25.5) for phorate sulfoxide, and 98.2 (6.02) for 2,4-D.     

Economic analysis of ethanol production in California using traditional and innovative feedstock supplies

In this article, we estimate the costs of using alternative feedstocks to produce ethanol in a 40 million-gal facility in California’s San Joaquin Valley. Feedstocks include corn imported from Midwestern states and locally grown agricultural products such as corn, grapes, raisins, oranges, and other tree fruits. The estimated feedstock costs per gallon of ethanol include $0.92 for Midwestern corn, $1.21 for locally grown corn, $6.79 for grapes, $3.36 for raisins, $3.92 for citrus, and $1.42 for other tree fruit. Adjusting for coproduct values lowers the estimated net feedstock costs to $0.67/gal of ethanol for Midwestern corn, $0.96 for locally grown corn, $6.53 for grapes, and $3.30 for raisins. We also examine the potential increases in net revenue to raisin producers, made possible by having an alternative outlet available for selling surplus raisins.     

Traditional medicine in Syria: folk medicine in Aleppo governorate

The use of Traditional Arabic Medicine (TAM) for various diseases has been popular but scarcely studied in Syria. In the present study, we carried out ethnobotanical and ethnopharmacological research on the plants traditionally used to cure various diseases in northern Syria. The information was collected from the city and villages of the Aleppo governorate "Mohaafazah" in the north of Syria, collecting data directly on the basis of a detailed survey of inhabitants and herbalists. In this survey, we found that hundreds of plant species are still in use in TAM for the treatment of various diseases. We selected the most common 100 species, used in the treatment of more than 25 diseases. Among these plants, 53 are used for treating gastrointestinal disorders, 38 for respiratory system diseases, including asthma, bronchitis and cough, 34 for skin diseases, 21 for diabetes, 17 for kidney and urinary disorders, 16 for cardiac disorders, 14 for infertility and sexual impotency, 13 for treating liver diseases, 13 for several types of cancer, 9 for enhancing breast milk excretion, 8 for weight loss, 5 for reducing cholesterol, and three for weight gain. Plants were collected and identified: scientific Latin names, local names, the used parts of the plant, the herbal preparations and the local medical uses are described. Scientific literature concerning the activity of the investigated species is also reported and discussed according to their traditional uses.     

A pilot study for the preparation of a new Reference Material based on antarctic krill

The preparation of new Certified Reference Materials (CRMs) of antarctic matrices forms the backbone of an ongoing project in the framework of the Italian National Program for Antarctic Research. The first CRM of this kind (MURST-ISS-A1 Antarctic Marine Sediment) is already available. The second phase focuses on the certification of antarctic krill, a small shrimp extremely abundant in the Southern Ocean. The total mass of krill available for this purpose is approximately 44 kg and results from the combination of three different catches (Ross Sea, Marguerite Bay and Livingston Island, respectively). The quantification of the following elements in the raw mass appears to be affordable by current analytical techniques, values being in the range of (in μg/g) 0.11–0.30 for As, 0.03–0.12 for Cd, 0.06–0.23 for Cr, 6.1–21 for Cu, 5.7–7.6 for Fe, 0.005–0.008 for Hg, 0.7–1.2 for Mn, 0.013– 0.077 for Ni, 0.04–0.57 for Pb and 12–16 for Zn. On the other hand, the average values ascertained in freeze-dried krill are as a rule one order of magnitude higher, i.e., (in μg/g), 3.2 for As, 0.6 for Cd, 1.8 for Cr, 75 for Cu, 61 for Fe, 0.025 for Hg, 4.6 for Mn, 0.7 for Ni, 2.1 for Pb and 81 for Zn. Information on the pretreatment of krill and details on the planned certification campaign are also given. Received: 10 June 1997 / Revised: 24 September 1997 / Accepted: 28 September 1997     

Modeling thermodynamic properties of natural gas mixtures using perturbed-chain statistical associating fluid theory

Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was employed for predicting thermodynamic properties of natural gas mixture. Thermodynamic properties like density, isobaric and isochoric heat capacity, enthalpy, entropy, and internal energy were calculated with the PC-SAFT. Results are validated against experimental data for natural gas and mixtures similar to natural gas. The validation show that the Average Absolute Deviation (AAD) for density is 1.10% for binary mixture and 1.08% for mixtures similar to natural gas. Also AAD value for enthalpy is 1.42%, for internal energy, 0.77, for entropy, 0.43, for isochoric heat capacity, 1.26%, and for isobaric heat capacity, 2.66%. Results show PC-SAFT to be able to predict all the thermodynamics properties of natural gas and mixtures similar to natural gas with high accuracy in a wide range of temperature and pressure.     

Isotope dilution high-resolution gas chromatography/high-resolution mass spectrometry method for analysis of selected acidic herbicides in surface water

In this work, an isotope dilution method for determination of selected acidic herbicides by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for surface water samples. Average percent recoveries of native analytes were observed to be between 70.8 and 93.5% and average recoveries of labeled quantification standards [(13)C(6)]2,4-D and [(13)C(6)]2,4,5-T were 85.5 and 101%, respectively. Using this method, detection limits of 0.05 ng/L for dicamba, MCPA, MCPP, and triclopyr, and 0.5 ng/L for 2,4-D were routinely achieved. The method was applied to measuring the concentration of these analytes in surface water samples collected from five sampling locations in the Lower Fraser Valley region of British Columbia, Canada. All of the herbicides monitored were detected at varying levels in the surface water samples collected. The highest concentrations detected for each analyte were 345 ng/L for 2,4-D, 317 ng/L for MCPA, 271 ng/L for MCPP, 15.7 ng/L for dicamba, and 2.18 ng/L for triclopyr. Average detection frequencies of the herbicides were 95% for MCPA, 80% for MCPP, 70% for dicamba, 65% for 2,4-D, and 46% for triclopyr. Seasonal variations of herbicide levels are also discussed.     

Optimization of parameters for semiempirical methods II. Applications

MNDO/AM1-type parameters for twelve elements have been optimized using a newly developed method for optimizing parameters for semiempirical methods. With the new method, MNDO-PM3, the average difference between the predicted heats of formation and experimental values for 657 compounds is 7.8 kcal/mol, and for 106 hypervalent compounds, 13.6 kcal/mol. For MNDO the equivalent differences are 13.9 and 75.8 kcal/mol, while those for AM1, in which MNDO parameters are used for aluminum, phosphorus, and sulfur, are 12.7 and 83.1 kcal/mol, respectively. Average errors for ionization potentials, bond angles, and dipole moments are intermediate between those for MNDO and AM1, while errors in bond lengths are slightly reduced.     

高效液相色谱法测定藻类中的类胡萝卜素和叶绿素

提出了用高效液相色谱法测定藻类中类胡萝卜素和叶绿素的方法。采用丙国等有机溶剂提取藻类中的类胡萝卜素和叶绿素,然后在反相C18柱上进行分离。流动相选用二氯甲烷／乙腈／甲醇／水（22.5:9.5:67.5:0.5）,流速为1.0mL／min。用光度检测器检测报长为450um。叶黄素、α-胡萝卜素、β-胡萝卜素、叶绿素a和叶绿素b的平均回收串分别为99.1％,98.5％,99.4％,100.6％和99.9％,相对标准偏差分别为2.4％,5.6％,6.0％,4.1％和4.0％。     

Spent Grain from Malt Whisky: Assessment of the Phenolic Compounds

In order to extract antioxidant phenolic compounds from spent grain (SG) two extraction methods were studied: the ultrasound-assisted method (US) and the Ultra-Turrax method (high stirring rate) (UT). Liquid to solid ratios, solvent concentration, time, and temperature/stirring rate were optimized. Spent grain extracts were analyzed for their total phenol content (TPC) (0.62 to 1.76 mg GAE/g SG DW for Ultra-Turrax pretreatment, and 0.57 to 2.11 mg GAE/g SG DW for ultrasound-assisted pretreatment), total flavonoid content (TFC) (0.6 to 1.67 mg QE/g SG DW for UT, and 0.5 to 1.63 mg QE/g SG DW for US), and antioxidant activity was measured using 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical (25.88% to 79.58% for UT, and 27.49% to 78.30% for UT). TPC was greater at a high stirring rate and high exposure time up to a certain extent for the Ultra-Turrax method, and at a high temperature for the ultrasound-assisted method. P-coumaric acid (20.4 ± 1.72 mg/100 SG DW for UT, and 14.0 ± 1.14 mg/100 SG DW for US) accounted for the majority of the phenolic found compounds, followed by rosmarinic (6.5 ± 0.96 mg/100 SG DW for UT, and 4.0 ± 0.76 mg/100 SG DW for US), chlorogenic (5.4 ± 1.1 mg/100 SG DW for UT, and non-detectable for US), and vanillic acids (3.1 ± 0.8 mg/100 SG DW for UT, and 10.0 ± 1.03 mg/100 SG DW for US) were found in lower quantities. Protocatechuic (0.7 ± 0.05 mg/100 SG DW for UT, and non-detectable for US), 4-hydroxy benzoic (1.1 ± 0.06 mg/100 SG DW for UT, and non-detectable for US), and caffeic acids (0.7 ± 0.03 mg/100 SG DW for UT, and non-detectable for US) were present in very small amounts. Ultrasound-assisted and Ultra-Turrax pretreatments were demonstrated to be efficient methods to recover these value-added compounds.     

Simultaneous quantification of five anthraquinones in rat plasma by high-performance liquid chromatography with fluorescence detection

A sensitive high-performance liquid chromatographic method with fluorescence detection (excitation 435 and emission 515 nm) was established and validated for quantification of five anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) in rat plasma. Following a single-step liquid-liquid extraction, the analytes and internal standard (1,8-dihydroxyanthraquinone) were separated on a reversed-phase C(18) column with water-phosphoric acid-methanol as mobile phase at a flow rate of 1 mL/min. The linear ranges of the calibration curves were 6.5-1300 ng/mL for aloe-emodin, 20-4000 ng/mL for rhein, 40-8000 ng/mL for emodin, 15-3000 ng/mL for chrysophanol and 13-2600 ng/mL for physcion. The lower limit of quantification was 6.5 ng/mL for aloe-emodin, 20 ng/mL for rhein, 40 ng/mL for emodin, 15 ng/mL for chrysophanol and 13 ng/mL for physcion. The mean accuracy was 94.3-105.1% for aloe-emodin, 90.3-108.8% for rhein, 92.6-106.7% for emodin, 95.8-103.8% for chrysophanol and 98.7-101.2% for physcion. The within-batch and between-batch precisions were < or = 5.5% and < or = 13.4%, respectively. This method is suitable for determining the five anthraquinones in plasma simultaneously and thus investigating the pharmacokinetics of anthraquinones from Xiexin decoction in rats.     

Heats of formation and kinetics of decomposition of nitroalkanes

Heats of formation of solid, liquid, and gaseous nitroalkanes have been shown mostly to obey group additivity. Group values have been obtained for carbon atoms attached to one, two, and three nitro groups. The heat of formation of 1,1,1,3,5,5,5,-heptanitropentane, either solid or liquid, cannot be fitted to the scheme, even allowing for gauche effects. The differences between observed and estimated values for 1,1,1-fluorodinitroalkanes and 1,2-dinitroethane are larger than expected and should be further investigated. Activation energies have been calculated for decomposition by five-center elimination of HONO from mononitro- and dinitroalkanes using thermochemistry and estimated activation energies for the reverse reactions. The key data for these estimates were previously reported activation energies for the decomposition of nitroethane and 1,2-dinitropropane. The calculations also gave values for the heats of formation (in kcal/mole) of nitroethylene 12.4, and 1-nitropropylene 5.6, and 2-nitropropylene 1.6. Activation energies were calculated for the competing unimolecular reaction, C? N bond fission, from thermochemistry and previously reported activation energies for the decomposition of 1,1- and 2,2-dinitropropane. Comparison of Arrhenius parameters for the two competing processes, namely, HONO and C? N bond fission, shows that, for the geminate dinitroethanes and dinitropropanes, C? N bond fission is faster about 370°K and, for the mononitroalkanes and for all the mononitroalkanes and dinitroalkanes, C? N bond fission is faster above 770°K.     

High-performance liquid chromatographic determination of hydrocortisone and methylprednisolone and their hemisuccinate esters in human serum

A high-performance liquid chromatographic method is described for the simultaneous determination of methylprednisolone (MP) and methylprednisolone hemisuccinate (MPHS), or hydrocortisone (HC) and hydrocortisone hemisuccinate (HCHS) in human serum. Reversed-phase liquid chromatography was performed on a microparticulate C18 column (Spherisorb, 5 micron) using a mobile phase of 2% glacial acetic acid, 30--35% acetonitrile, 70--65% water with ultraviolet detection (254 nm). The method uses 17 alpha-hydroxyprogesterone as the internal standard for the determination of methylprednisolone and its hemisuccinate ester, or 11-deoxy-17-hydroxycorticosterone as the internal standard for the determination of hydrocortisone and its hemisuccinate ester. The sensitivity is 0.03 microgram/ml for HC, 0.07 microgram/ml for MP, 0.04 microgram/ml for MPHS, and 0.10 microgram/ml for HCHS, with a detection limit of 0.02 microgram/ml for all four steroids. Calibration curves are linear up to 3 micrograms/ml for MP or MPHS (as equivalent MP) and up to 4 micrograms/ml for HC and 7 micrograms/ml (as equivalent HC) for HCHS. The pooled relative standard deviation for replicate for each steroid is less than 7%. Plasma concentration--time curves are reported for MP and MPHS or HC and HCHS of two human subjects following intramuscular administration of 125 mg of methylprednisolone sodium succinate for injection, U.S.P., or 250 mg of hydrocortisone sodium succinate for injection, U.S.P.     

Effects of gamma irradiation on cell-wall constituents of some agricultural residues

The effects of 150 kilogray (kGy) of γ irradiation on cell-wall constituents of cottonwood (CW), lentils straw (LS), apple pruning products (AP) and olive cake (OC) were investigated. Samples were irradiated by γ irradiation at a dose level of 150 kGy under identical conditions of temperature and humidity and analyzed for crude fibre (CF), neutral-detergent fibre (NDF), acid detergent fibre (ADF) and acid-detergent lignin (ADL). The results indicate that γ irradiation decreased CF contents by about 29% for CW, LS and AP and by 17% for OC. NDF values were also decreased by about 4% for CW and OC, and by about 12% for LS and AP. γ Irradiation treatment also decreased ADF values only for CW by 8%. ADL contents decreased by 8% for CW and 5% for OC with no effects for LS and AP. The percentage of cellulose (CL): CF ratio increased by 30, 34, 38 and 20% for CW, LS, AP and OC, respectively. Also, the percentage of hemicellulose (HCL): CF increased by 57% for CW and 16% for OC and decreased by 7% for LS and AP. The percentage of HCL: ADL increased by 22% for CW but decreased by 33% for LS and AP with no changes for OC. There were no changes in CL: ADL ratio for all residues.     

Determination of fumonisins B1 and B2 in corn and corn flakes by liquid chromatography with immunoaffinity column cleanup: collaborative study.

A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 microg/g for FB1 and from <0.05 to 0.56 microg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 microg/g for FB1 and from <0.05 to 0.46 microg/g for FB2. The method involved double extraction with acetonitrile-methanol-water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21 % for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 microg/g and with FB2 at 0.40 microg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.