Laboratory guidelines and standards in clinical and forensic toxicology

An overview is given of the existing standards and guidelines for analytical toxicology. Details about guidelines concerning forensic toxicology, clinical toxicology, point-of-care testing, and an area of overlap are provided. Guidelines and standards exist for forensic toxicological analysis in general and for specific situations, e.g., workplace drug testing and driving under the influence of drugs and alcohol. For workplace drug testing, detailed guidelines exist in the U.S.A., Australia, and Europe describing for example the methods used, their cut-off and the process of sample handling. Some governments describe the methods and quality requirements for blood alcohol testing for driving under the influence of alcohol in detail in their laws. In the area of clinical toxicology, guidelines not only focus on the analytical aspects of analysis but also on the timeliness of results. According to the US- and UK-based practice guidelines for the emergency department, the turn-around time should be 1 or 2 h, respectively, for a specific set of analytes. Guidelines are either being developed now or already available (e.g., workplace drug testing, breath alcohol analysis) for point-of-care testing in analytical toxicology. In the context of brain death and sexual assault cases, specific demands need to be imposed because of the unique aspects of drug analysis in these situations (variety of drugs used, low concentrations). Many guidelines and standards are available and it is up to every laboratory to choose the best ones depending on the area of activity and the legal and regulatory environment.Presented at the 10th Conference Quality in the Spotlight, March 2005, Antwerp, Belgium     

Tune-out and magic wavelengths for hydrogenlike and screened-hydrogenlike atoms

The tune-out and magic wavelengths (TMWs) for the hydrogenlike and screened-hydrogenlike atoms (Z = 1-8) are calculated using a variational method. The first three tune-out wavelengths for each of the nS (n = 1, 2, 3) states and the first three magic wavelengths for each of the 1S-nS (n = 2, 3) transitions of the hydrogenlike atoms in terms of nuclear charge Z, and the first TMWs for the above mentioned states or transitions of the screened-hydrogenlike atoms in terms of the screening parameter μ and Z are presented. All the results for the TMWs are reported for the first time in the literature except the magic wavelengths for the hydrogen atom. The magic wavelengths for hydrogen atom are in agreement with the available data. The precise estimation of the TMWs would be helpful for the design of the ion-trapping experiment of the hydrogenic systems. Our study is expected to be useful for the measurements of the hydrogenic 1S-2S and 1S-3S transitions spectroscopy for the improved accuracy.     

Circular dichroism and conformational dynamics of cephams and their carba and oxa analogues

The biological activity of bicyclic beta-lactam antibiotics depends strongly on the absolute configuration of the bridgehead carbon atom. Frelek and co-workers proposed an empirical helicity rule relating the configuration of the bridgehead carbon atom to the sign of the 220 nm band in the electronic circular dichroism (CD) spectrum of beta-lactams. Here we use synthetic organic chemistry, CD spectroscopy, and time-dependent density functional theory (TDDFT) to investigate the validity of this structure-property relationship for eight model compounds. For conformationally flexible beta-lactams, substantial thermal effects are found which must be included in calculations. To this end, we combine TDDFT calculations of CD with full quantum-mechanical Born-Oppenheimer molecular dynamics (MD) simulations for the first time. The CD spectra are sampled with ground-state density functional trajectories of up to 60 ps. The MD simulations show a surprisingly high sensitivity of the CD to the molecular conformation. On the other hand, the relation between CD and thermally averaged structural parameters is much less complex. While the helicity rule does not seem to hold for individual conformers, it is confirmed by the calculations for seven out of eight systems studied if thermally averaged CD spectra and structures are considered. Since thermal effects on CD can be larger than typical inherent inaccuracies of TDDFT, our results emphasize the need for a systematic treatment of conformational dynamics in CD calculations even for moderately flexible systems. Temperature-dependent CD measurements are very useful for this purpose. Our results also suggest that CD spectroscopy may be used as a sensitive probe of conformational dynamics if combined with electronic structure calculations.     

NaP4及其正负离子的结构和光谱性质

用密度泛函理论(DFT)分析了NaP4及其正负离子的低级电子态的平衡结构、振动频率、能量、原子化能、绝热电子亲合能、绝热离子势等, 并与实验所得的阴离子光电子能谱进行比较. 根据计算结果与实验所得的激发能进行比较, 对NaP-4的阴离子光电子能谱中的峰进行了合理的归属.     

Efficient and Sensitive Method for Quantitative Determination and Validation of Umbelliferone, Carvone and Myristicin in Anethum graveolens and Carum carvi Seed

An efficient HPTLC method for the analysis of umbelliferone, carvone and myristicin in Anethum graveolens and Carum carvi seed was developed. The method employed HPTLC plates precoated with silica gel 60 F₂₅₄ as the stationary phase. Methanol extracts of seeds from three different sources were used. The calibration plot for umbelliferone, carvone and myristicin were linear with the correlation coefficient of 0.997 ± 0.016, 0.999 ± 0.009 and 0.999 ± 0.013, respectively, which were indicative of good linear dependence of peak area on concentration. The method permits reliable quantification of umbelliferone, carvone and myristicin and showed good resolution and separation. The method was validated as per ICH guidelines. To study the accuracy of the method, recovery studies were performed by the method of standard addition at three different levels and the average percentage recovery was found to be 99.05% for umbelliferone, 100.28% for carvone and 99.8% for myristicin. The proposed HPTLC method for quantitative monitoring of umbelliferone, carvone and myristicin in A. graveolens and C. carvi seed can be used for routine quality testing of these extracts.     

Interactions between temozolomide and guanine and its S and Se‐substituted analogues

Temozolomide was paired with guanine, 6‐selenoguanine, and 6‐thioguanine, as well as the SH tautomer of the latter. The potential energy surface of each heterodimer was searched for all minima, using Dispersion‐Corrected Density Functional Theory and MP2 methods. Among the dozens of minima, three categories were observed. Stacked geometries place the aromatic systems of the two molecules parallel to one another, while the two systems are roughly perpendicular to one another in a second category. Also found are coplanar structures held together by H‐bonds. Dispersion proves to be a dominating attractive force for the stacked structures, less so for perpendicular, and smallest for the coplanar dimers. Geometries and energetics are relatively insensitive to S and Se substitution, but tautomerization reverses relative stabilities of different geometries.     

Industrial development and applications of plant oils and their biobased oleochemicals

In the concepts for new products, performance, product safety, and product economy criteria are equally important. They are taken into account already when the raw materials base for a new industrial product development is defined. Here, renewable resources gain-again after the earlier “green trend” in the 1980s—increasing attention as an alternative raw materials source compared to fossil feedstock. The industrial use of carbohydrates, proteins, and plant oils aligns perfectly with the principles of Responsible Care and is an important part of green chemistry and sustainability in general. Since the 1950s, oleochemistry has grown to a major research and technology area in several institutions and industries. A large variety of products based on fats and oils have been developed since then for different uses, such as specialties for polymer applications, biodiesel, surfactants, emollients for home and personal-care industries, pesticides and biodegradable mineral oil replacements for lubricants. However, at present it seems that the use of renewable resources, especially plant oils, has to compete more and more with the increasing demand for bioenergy, which could cause an unbalanced supply and demand in the future or even a threat for the increasing demand for food in certain areas of the world.     

Structures and Spectroscopic Properties of NaAs4 and Its Anions and Cations

The equilibrium geometries, vibrational frequencies, atomization energies, adiabatic electron separations, adiabatic detachment energies （ADE）, and adiabatic ionization potentials of the low-lying electronic states for the NaAs4 clusters and its ions were investigated employing the DFT method, and then compared with the photoelectron spectra. According to the computed results, reasonable assignments for the photoelectron spectra of NaAs4^- were suggested.     

哺乳母婴及非哺乳母婴全血中三种元素含量分析研究

通过对西安地区哺乳母婴及非哺乳母婴三种元素含量检测的对比观察，研究了哺乳期母婴体内锌、铁、钙三种重要必需元素情况，为今后儿童营养指导，儿童营养品的生产和加工提供参考。     

Identification and quantification of nucleosides and nucleobases in Geosaurus and Leech by hydrophilic-interaction chromatography

A simple hydrophilic-interaction chromatography (HILIC) method was developed for the identification and quantification of 14 nucleosides and nucleobases, namely cytosine, uracil, cytidine, guanine, hypoxanthine, xanthine, uridine, thymine, inosine, guanosine, thymidine, 2′-deoxyadenosine, 2′-deoxyinosine and 2′-deoxyuridine in two traditional Chinese medicines, Geosaurus and Leech. The separation was achieved on a TSKgel Amide-80 column (150 mm × 2.0 mm, 3.0 μm) with a mixture of acetonitrile and 10 mM aqueous ammonium acetate as the mobile phase at a flow rate of 0.2 mL/min. The temperature was set at 30 °C and UV detection wavelength was set at 260 nm. All calibration curves showed good linearity (R² > 0.9957) within the test ranges. The overall intra- and inter-day RSD ranged from 0.4 to 3.4% and from 0.7 to 3.3%, respectively. The LOD and LOQ were in the range of 0.07-30.49 ng/mL and 0.26-60.98 ng/mL, respectively. The repeatability of the method was in the range of 2.2-5.8% for Geosaurus and 1.4-5.5% for Leech. The recoveries of the samples were in the range of 91.4-100.9% for Geosaurus, and 91.9-99.3% for Leech. The established method was applied successfully for the analysis of nucleosides and nucleobases in 22 commercially available samples collected from different regions in China and Japan. Our data showed that HILIC had advantages as a useful tool for the study of the bioactive components in Geosaurus and Leech as well as their quality control, and could therefore be used for the determination of the analytes in pharmaceutical products and biological fluids.     

Spectrophotometric study of the reaction mechanism between DDQ as pi-acceptor and potassium iodate and flucloxacillin and dicloxacillin drugs and their determination in pure and in dosage forms

Two simple and accurate spectrophotometric methods are presented for the determination of beta-lactam drugs, flucloxacillin (Fluclox) and dicloxacillin (Diclox), in pure and in different pharmaceutical preparations. The charge transfer (CT) reactions between Fluclox and Diclox as electron donors and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) pi-acceptor and potassium iodate via oxidation reduction reaction where the highly coloured complex species or the liberated iodine have been spectrophotometrically studied. The optimum experimental conditions have been studied carefully. Beer's law is obeyed over the concentration range of 2-450 microg ml(-1) for Fluclox and 10-450 microg ml(-1) for Diclox using DDQ reagent and at 50-550 microg ml(-1) for Fluclox and 50-560 microg ml(-1) for Diclox using iodate method, respectively. For more accurate results, Ringbom optimum concentration range is calculated and found to be 6-450 and 15-450 microg ml(-1) for Fluclox and Diclox using DDQ, respectively, and 65-550 and 63-560 microg ml(-1) for Fluclox and Diclox using iodine, respectively. The Sandell sensitivity is found to be 0.018 and 0.011 microg cm(-2) for DDQ method and 0.013 and 0.011 microg cm(-2) for iodate method for Fluclox and Diclox, respectively, which indicates the high sensitivity of both methods. Standard deviation (S.D.=0.01-0.80 and 0.07-0.98) and relative standard deviation (R.S.D.=0.13-0.44 and 0.11-0.82%) (n=5) for DDQ and iodate methods, respectively, refer to the high accuracy and precision of the proposed methods. These results are also confirmed by between-day precision of percent recovery of 99.87-100.2 and 99.90-100% for Fluclox and Diclox by DDQ method and 99.88-100.1 and 99.30-100.2% for Fluclox and Diclox by iodate method, respectively. These data are comparable to those obtained by British and American pharmacopoeias assay for the determination of Fluclox and Diclox in raw materials and in pharmaceutical preparations.     

Monte Carlo simulations and analysis of scattering from neutral and polyelectrolyte polymer and polymer-like systems

Methods for analyzing small-angle scattering data from complex liquids with particles with many internal degrees of freedom have progressed substantially during the past years. This is mainly due to the use of Monte Carlo simulation techniques for obtaining scattering functions and the use of an approach in which the obtained scattering functions are subsequently parameterized, so that they can be used for data fitting. The present paper reviews recent applications of the Monte Carlo technique for obtaining parameterized scattering functions, and the application of these with emphasis on semiflexible polymers and wormlike micelle systems with and without electrostatic interactions.     

Prospects and crucial problems in oligomerization and polymerization with iron and cobalt complex catalysts

<正>The discovery of highly active 2,6-bis(imino)pyridyl iron and cobalt complexes provided a milestone of latetransition metal catalysts for ethylene oligomerization and polymerization with being currently investigated for the scale-up process.The crucial problems are remaining in the catalytic systems:the catalytic systems targeting ethylene polymerization produce more oligomers at elevated reaction temperatures,however,there is a recognizable amount of high-molecular-weight polyethylene remained in the modified catalytic system for the oligomerization process.Beyond the modification of bis(imino)pyridyl metal complexes,several alternative procatalysts' models have been developed in our group.This review highlighted the achievements in exploring new iron and cobalt complexes with tridentate NNN ligands as procatalysts for ethylene oligomerization and polymerization.     

Plasma homo- and copolymerizations of tetrafluoroethylene and chlorotrifluoroethylene

The plasma homo- and copolymerizations of tetrafluoroethylene (TFE) and chlorotrifluoroethylene (CTFE) in a capacitively coupled tubular reactor (TR) with external electrodes were studied by means of microgravimetry and FT-IR and XPS analyses. The deposition rates for CTFE/TFE plasma copolymers, as well as the ratios of IR absorbances at 1180 and 1225 cm⁻¹, and the XPS-derived Cl/C and F/C ratios, varied regularly with mol % CTFE in the feed, all of which results were dependent upon the rf power at which the plasma copolymerizations were conducted. The deposition rates for the plasma homopolymers of TFE (PPTFE) and CTFE (PPTCFE) depended markedly on rf power (W) and monomer molar flow rate (F). The F/C ratio for PPTFE was nearly independent of the composite parameter,W/FM (whereM is the monomer molecular weight), while for PPCTFE, the F/C ratio decreased significantly and the Cl/C ratio increased slightly with increase inW/FM. The percentage of carbon as CF₃ was 20–24% in PPTFE and 7–14% in PPCTFE. Plots of deposition rate versusW/FM for PPTFE and PPCTFE obtained in a TR differed considerably from corresponding plots in the literature for the same homopolymers prepared in a glass-cross or bell-jar reactor.     

Correlation and prediction of partition coefficient between the gas phase and water, and the solvents dry methyl acetate, dry and wet ethyl acetate, and dry and wet butyl acetate

Experimental partition coefficient data have been compiled from the published literature for the water/methyl acetate, water/ethyl acetate and water/butyl acetate partition systems, log P data, and for the gas/methyl acetate, gas/ethyl acetate and gas/butyl acetate partition systems, log K data. Application of the Abraham solvation parameter model to the sets of partition coefficients leads to equations that correlate the log P data and log K data to 0.18 log units for the three dry alkyl acetate solvents. Slightly larger deviations were noted for solute partition into both wet ethyl acetate and wet butyl acetate. The derived correlations were validated using training set and test set analyses.     

Rapid and Highly Sensitive HPLC and TLC Methods for Quantitation of Amlodipine Besilate and Valsartan in Bulk Powder and in Pharmaceutical Dosage Forms and in Human Plasma

Two simple, sensitive, and specific high-performance liquid chromatography and thin-layer chromatography methods were developed for the simultaneous estimation of Amlodipine besilate (AM) and Valsartan (VL). Separation by HPLC was achieved using a xTerra C18 column and methanol /acetonitrile /water/ 0.05% triethylamine in a ratio 40:20:30:10 by volume as mobile phase, pH was adjusted to 3 ± 0.1 with o-phosphoric acid. The flow rate was 1.2 mL min^?1. The linearity range was 0.2 to 2 µg mL^?1 for amlodipine besilate and 0.4 to 4 µg mL^?1 for Valsartan with a mean percentage recovery of 99.59 ± 0.523% and 100.61 ± 0.400% for amlodipine besilate and valsartan, respectively. The TLC method used silica gel 60 F₂₅₄ plates; the optimized mobile phase was ethyl acetate/ methanol / ammonium hydroxide (55:45:5 by volume). Quantitatively, the spots were scanned densitometrically at 237 nm. The range was 0.5–4.0 µg spot^?1 for amlodipine besilate and 2.0–12.0 µg spot^?1 for valsartan. The mean percentages recovery was 99.80 ± 0.451% and 100.61 ± 0.363% for amlodipine besilate and valsartan, respectively. The HPLC method was found to be simple, selective, precise, and reproducible for the estimation of both drugs from spiked human plasma.     

Rapid and simple determination of aldose reductase and sorbitol dehydrogenase

Rapid and well-reproducible methods were developed for the determination of aldose reductase and sorbitol dehydrogenase. The aldose reductase activity measurement is based on photometric o-toluidine aldose back-measurement, which is widely used in laboratories for the quantitative determination of glucose. The spectrophotometric method based on the quantitative decrease in NADH proved suitable for the measurement of sorbitol dehydrogenase activity.Both methods could well be employed for the measurement of the aldose reductase and sorbitol dehydrogenase activities of normal and diabetic tissue homogenizates, and for the comparison of the measured values.     

Spectrophotometric study of the reaction mechanism between DDQ Pi- and iodine sigma-acceptors and chloroquine and pyrimethamine drugs and their determination in pure and in dosage forms

Two simple and accurate spectrophotometric methods are presented for the determination of anti-malarial drugs, chloroquine phosphate (CQP) and pyrimethamine (PYM), in pure and in different pharmaceutical preparations. The charge transphere (CT) reactions between CQP and PYM as electron donors and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) pi-acceptor and iodine sigma-acceptor reagents to give highly coloured complex species have been spectrophotometrically studied. The optimum experimental conditions have been studied carefully. Beer' law is obeyed over the concentration range of 1.0-15 microg ml(-1) for CQP and 1.0-40 microg ml(-1) for PYM using I(2) and at 5.0-53 microg ml(-1) for CQP and 1.0-46 microg ml(-1) for PYM using DDQ reagents, respectively. For more accurate results, Ringbom optimum concentration range is calculated and found to be 10-53 and 8-46 microg ml(-1) for CQP and PYM using DDQ, respectively and 5-15 and 8-40 microg ml(-1) for CQP and PYM using iodine, respectively. The Sandell sensitivity is found to be 0.038 and 0.046 g cm(-2) for DDQ method and 0.0078 and 0.056 g cm(-2) for I(2) method for CQP and PYM, respectively which indicates the high sensitivity of both methods. Standard deviation (S.D.=0.012-0.014 and 0.013-0.015) and relative standard deviation (R.S.D.=0.09-1.4 and 1.3-1.5%) (n=5) for DDQ and I(2) methods respectively, refer to the high accuracy and precision of the proposed methods. These results are also confirmed by between day precision of percent recovery of 99-100.6%, and 98-101% for CQP and PYM by DDQ method and 99-102% and 99.2-101.4% for CQP and PYM by I(2) method respectively. These data are comparable to those obtained by British and American pharmacopoeias assay for the determination of CQP and PYM in raw materials and in pharmaceutical preparations.     

基因传感技术及目前存在的问题和发展对策

对最近几年报道的比较有特色的光学、压电、电化学等基因(DNA)传感器方面的研究工作进行介绍,并就目前基因传感器研究中存在的问题进行了分析讨论,提出了相应的发展对策.     

Epoxy and polyurethane adhesive materials of elad,aquapol, and acrolat brands and their components

Different groups of chemical products developed and produced at the Macromer Scientific and Manufacturing Company are described and recommended for use in adhesive compositions, including reactive diluents for epoxy compositions, urethane prepolymers, binders for photocurable materials, aqueous polyurethane dispersions. The main characteristics of binders for glues are presented, as well as the prospects for their application in formulas of adhesive compositions.