Characterization of Portuguese geomaterials,the clay component of <Emphasis Type="Italic">rañas</Emphasis>, as potential liners for low and intermediate radioactive disposal sites

This paper describes the development of a separation method for americium from the effluents emanating from anion exchange column, used for the recovery of plutonium from analytical waste solutions. The waste contained uranium, sodium, calcium and iron as the major impurities as estimated by ICP-AES method. ~99% pure americium was obtained by three separation steps using solvent extraction and extraction chromatography techniques. In the first step, uranium was quantitatively separated by giving five contacts of equal volumes of 30% TBP in n-dodecane. Fe and Na were separated in the next step using 0.1 M TODGA + 0.5 M DHOA as the extractant. In the last step, Am was separated from the co-extracted Ca (about 76%) using CMPO loaded extraction chromatographic column. The overall recovery was >80% with decontamination factor (D.F.) from the impurities being >3000 while the purity of the product was 99%.     

超高效液相色谱-串联质谱法同时测定食用油中痕量的δ-9-四氢大麻酚、大麻酚和大麻二酚

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定食用油中δ-9-四氢大麻酚(THC)、大麻酚(CBN)和大麻二酚(CBD)的方法。目标分析物经甲醇提取、中性氧化铝固相萃取柱净化后,采用UPLC-MS/MS分离和检测。实验以氘代四氢大麻酚(THC-D3)为内标物,采用同位素内标法定量。在3个添加水平下,目标物的平均回收率为68.0%～101.6%,相对标准偏差为7.0%～20.1%。方法检出限为0.06～0.17 μg/kg,定量限为0.20～0.52 μg/kg。该方法能够满足食用油中痕量四氢大麻酚、大麻酚和大麻二酚检测的需要。     

Determination of biogenic amines as dansyl derivatives in intestinal digesta and feces by reversed phase HPLC

Summary A new method was developed for the determination of fifteen biogenic amines in the intestinal digesta and feces of animal or human origin. The method involves the addition of an internal standard (heptylamine), extraction of the amines, and precipitation of the proteins with perchloric acid. The amines are derivatised with dansyl chloride, separated on a C18 column using gradient elution with 0.2M ammonium acetate at pH 5, water and acetonitrile, and detected with a fluorescence detector. The separation was achieved in a 40 min run. Recoveries ranged from 67 to 110%, the relative standard deviation for intra-assay precision being <5% and the limit of determination 1–5 mg kg⁻¹. The method is specific for biogenic amines in intestinal and fecal samples.     

Detection of albiflorin and paeoniflorin in Paeoniae Radix by reversed-phase high-performance liquid chromatography with pulsed amperometric detection

We have developed a reversed-phase high-performance liquid chromatography-pulsed amperometric detection (RP-HPLC-PAD) method for the detection of albiflorin and paeoniflorin in Paeoniae Radix and Wu-ji-san. Albiflorin and paeoniflorin were completely separated using 10% acetonitrile in 5 mM sodium phosphate buffer (pH 3.0) as an eluent and detected by PAD under alkaline conditions after using a post-column delivery system. The limit of detection (S/N = 3) and the limit of quantification (S/N = 10) were 0.10 and 0.35 ng for albiflorin, and 0.20 and 0.50 ng for paeoniflorin, respectively. The coefficients of linear regression were 0.9995 and 0.9999 for concentrations between 0.035 and 100 μg/mL. The intra- and inter-day precision (RSDs) was less than 3.56% in Paeoniae Radix and Wu-ji-san. The average recoveries from Paeoniae Radix and Wu-ji-san were 99.01–100.94% and 99.46–100.64%. This method shows higher selectivity than HPLC–UV method for analyzing albiflorin and paeoniflorin in Chinese medicinal preparation.     

Determination of ethyl glucuronide in urine using reversed-phase HPLC and pulsed electrochemical detection (Part II)

A direct, versatile method for the determination of ethyl glucuronide (EtG), a biomarker of ethanol consumption, in urine has been developed using reversed-phase liquid chromatography with pulsed electrochemical detection (PED). EtG and methyl glucuronide (MetG), which serves as an internal standard, are readily separated using a mobile phase consisting of 1% acetic acid/acetonitrile (98/2, v/v). Post-column addition of NaOH allows for the detection of all glucuronides using PED at a gold working electrode. Upon optimization, EtG was found to have a limit of detection of 0.03 μg/mL (7 pmol; 50 μL injection volume) and repeatability at the limit of quantitation of 1.7%R.S.D. (relative standard deviation). Solid-phase extraction (SPE) using an aminopropyl phase was used to remove interferents in urine samples prior to their analysis. Compound recovery following SPE was approximately 50 ± 2%. The forensic utility of this method was further validated by the analysis of 29 post-mortem urine specimens, whose results agreed strongly with certified determinations.     

Separation of no-carrier-added Tl and Pb radionuclides using poly(N-vinylpyrrolidone)

No-carrier-added (nca) ^199–201Tl has been separated from nca ^199–201Pb using an environmentally friendly biocompatible polymer, poly(N-vinylpyrrolidone). The method uses no harmful chemicals and is based on the process of dialysis of PVP-Pb and PVP-Tl complexes against triple-distilled water. It has been observed after one hour of dialysis that 75–85% Tl (in both +3 and +1 oxidation states) comes out of dialysis sack without any contamination from lead.     

Separated internal force constants for the ethylene and ethane molecules and their use for calculation of the force field for the propylene molecule

We consider the question of separation of linear combinations of force constants for ethylene and ethane. Introduction of a perturbation into the matrix of the kinematic coefficients allows us to solve the inverted vibrational problem using the matrix method of successive approximations without eliminating dependent coordinates. Such an approach makes it possible to obtain a sufficient system of equations for determining the separated internal force constants. The separated internal force constants determined for ethylene and ethane are used to calculate the force field for propylene. The calculated separated internal force constants for propylene reproduce its vibrational spectrum and the spectrum or propylene-d₆ with average deviation from experimental frequencies of 8 cm^–1. The numerical influence coefficients for stretching vibrations of the C-H bond are linearly related to the lengths of these bonds.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 1, pp. 118–122, Janauary–February, 1986.     

On-line purge and trap gas chromatography for monitoring of trihalomethanes in drinking water distribution systems

A method using an automated on-line purge and trap gas chromatograph with a dry electrolytic conductivity detector (DELCD) has been developed for monitoring four regulated trihalomethanes in drinking water distribution systems. This analyzer samples trihalomethanes from drinking water by pervaporation through a silicone capillary membrane contained within a gas extraction cell (GEC) followed by preconcentration using an adsorbent trap. Trihalomethanes are subsequently desorbed from the trap onto a capillary column, separated and detected. The analyzer operates in real-time, samples directly from the drinking water distribution system and is fully automated. The optimization, operation, and evaluation of the analyzer and method are discussed. Method detection limits (MDL) are less than 1.0 μg L⁻¹ with acceptable estimates for accuracy, and precision. The results from two on-line monitoring studies in chlorinated and chloraminated distribution systems are presented. The performance of the method is compared directly to United Stated Environmental Protection Agency Method 502.2 and shows a very slight, but acceptable bias.     

Plutonium and uranium determination in environmental samples: combined solvent extraction-liquid scintillation method

A method for the determination of uranium and plutonium by a combined high-resolution liquid scintillation-solvent extraction method is presented. Assuming a sample count equal to background count to be the detection limit, the lower detection limit for these and other alpha-emitting nuclides is 1·0 dpm with a Pyrex sample tube, 0·3 dpm with a quartz sample tube using present detector shielding or 0·02 d.p.m. with pulse-shape discrimination. Alpha-counting efficiency is 100%. With the counting data presented as an alpha-energy spectrum, an energy resolution of 0·2–0·3 MeV peak half-width and an energy identification to ±0·1 MeV are possible. Thus, within these limits, identification and quantitative determination of a specific alpha-emitter, independent of chemical separation, are possible. The separation procedure allows greater than 98% recovery of uranium and plutonium from solution containing large amounts of iron and other interfering substances. In most cases uranium, even when present in 10⁸-fold molar ratio, may be quantitatively separated from plutonium without loss of the plutonium. Potential applications of this general analytical concept to other alpha-counting problems are noted. Special probelems associated with the determination of plutonium in soil and water samples are discussed. Results of tests to determine the pulse-height and energy-resolution characteristics of several scintillators are presented. Construction of the high-resolution liquid scintillation detector is described.     

Simultaneous determination of sex hormones in egg products by ZnCl2 depositing lipid, solid-phase extraction and ultra performance liquid chromatography/electrospray ionization tandem mass spectrometry

A method was developed for simultaneous determination of residues of 17 sex hormones in egg products. Target compounds were extracted from samples with methanol in an ultrasonic bath, effectively separated from lipids in the extracts by ZnCl₂ depositing filtration and purified using a C₁₈ solid-phase extraction (SPE) and followed by NH₂ SPE cartridge. The analytes were quantified by liquid chromatography using a BEH C₁₈ column coupled to an electrospray ionization tandem mass spectrometer (LC-ESI-MS/MS) operating in negative mode for estrogens and in positive multiple reaction monitoring mode for androgens. The parameters of the mass spectrometer and the composition of mobile phase and additives were also optimized to enhance detection sensitivity. Average recoveries of the target compounds varied from 70.0% to 121.0% with relative standard deviations ranging from 2.3% to 11.2% at two fortification levels. The limits of detection (LOD) of the method were from 0.002 μg kg⁻¹ to 0.23 μg kg⁻¹ and the limits of quantification (LOQ) were in the range of 0.007-0.76 μg kg⁻¹.     

Multiresidue analysis of three groups of pesticides in washing waters from olive processing by solid-phase extraction-gas chromatography with electron capture and thermionic specific detection

A multiresidue solid phase extraction-gas chromatography (SPE-GC) method is developed for the analysis of 28 organochlorine (OCPs), organophosphorus (OPPs) and organonitrogen (ONPs) pesticides at ng l^− 1 levels in washing water from olive processing. Pesticides are separated from the water matrix, containing estimable amounts of olive oil, by eluting them from a C₁₈ SPE cartridge using dichloromethane. The target compounds are determined in the final extract by gas chromatography using thermionic specific (TSD) and electron capture (ECD) detection. Recoveries range from 79% to 129% in spiked washing water samples and detection limits are between 1 and 4 ng l^− 1. The method was successfully applied to determine OCPs, OPPs and ONPs in 25 samples of water collected directly in the inlet and outlet of the washing devices of three olive mills at different locations in Jaén (Spain). The most frequently encountered pesticide residues were terbuthylazine, simazine and diuron. In some of the water samples coming from the inlet of the washing devices, terbuthylazine and diuron measured concentrations were above the concentration limits scheduled by law.     

Trennung von V,Cr und Mn aus Stahl und Aktivierungsanalyse der Legierungselemente mit 14 MeV-Neutronen

The elements are separated from iron by solvent-extraction. Cr, V and Mn are separated by ion-exchange chromatography with a strong acidic cation-exchanger. The elements are determined by 14 MeV-neutron activation analysis using γ-spectroscopy. The method is suitable for a concentration range of 0.05 to 5%.     

Radiochemical separation and determination of europium by Ge(Li) detector in biological tissues

A simple neutron activation method has been developed for the determination of europium in biological tissues and applied in the analysis of marine organism samples with ±9% precision at the nanogram level. The method is based on the separation, by ion-exchange, of the rare earth group from dry or ashed irradiated tissues and subsequent determination of^152mEu, by γ-spectrometry using a lithium drifted germanium detector.^152mEu, separated almost completely from other than rare earth elements, with better than 98% chemical yield, is counted on the 121.8 keV photopeak which then is practically free from any other γ-ray energy interfering in this counting.     

Eco-Friendly,Simple, Fast,and Sensitive UPLC-MS/MS Method for Determination of Pexidartinib in Plasma and Its Application to Metabolic Stability

Pexidartinib is the first drug approved by the U.S. Food and Drug Administration specifically to treat the rare joint tumor tenosynovial giant cell tumor. In the current study, a validated, selective, and sensitive UPLC-MS/MS assay was developed for the quantitative determination of pexidartinib in plasma samples using gifitinib as an internal standard (IS). Pexidartinib and IS were extracted by liquid-liquid extraction using methyl tert-butyl ether and separated on an acquity BEH C₁₈ column kept at 40 °C using a mobile phase of 0.1% formic acid in acetonitrile: 0.1% formic acid in de-ionized water (70:30). The flow rate was 0.25 mL/min. Multiple reaction monitoring (MRM) was operated in electrospray (ESI)-positive mode at the ion transition of 418.06 > 165.0 for the analyte and 447.09 > 128.0 for the IS. FDA guidance for bioanalytical method validation was followed in method validation. The linearity of the established UPLC-MS/MS assay ranged from 0.5 to 1000 ng/mL with r > 0.999 with a limit of quantitation of 0.5 ng/mL. Moreover, the metabolic stability of pexidartinib in liver microsomes was estimated.     

Determination of baicalin, chlorogenic acid and caffeic acid in traditional chinese medicinal preparations by capillary zone electrophoresis

Summary A capillary zone electrophoresis (CZE) method was developed for the simultaneous assay of three bioactive components—baicalin, chlorogenic acid and caffeic acid—in seven traditional Chinese medicinal preparations. The analytes were separated successfully within 3.5 min using 10 mM borate buffer (pH8.6). Regression equations revealed linear relationships (correlation coefficients 0.9942–0.9996) between the peak area and concentration of the three analytes. The relative standard deviations of the migration times and the peak areas of the three constituents were 1.12–2.68% and 1.62–5.73%, respectively. Recovery of the three constituents ranged from 89 to 107%. The extraction efficiencies of different extraction solutions are also discussed. The contents of the three components in seven different Chinese medicinal preparations containing Honeysuckle flower and/orScutellariae radix were determined by the CZE method with satisfactory results.     

Separation and determination of organic acids and inorganic anions in Bayer liquors by ion chromatography after solid-phase extraction

An ion chromatographic (IC) method for the determination of six organic acids and three inorganic anions in Bayer liquors was proposed. Formic, acetic, propionic, oxalic, succinic, glutaric acid, F⁻, Cl⁻, and SO ₄ ²⁻ were separated and determined within 33 min. For the first time, repeatability, reproducibility, and recoveries for the determination of these acids in Bayer liquors were estimated. The analytes were removed from a Bayer liquor by using an ion-exchange resin column. The chromatographic separation was achieved with only one IonPac AS11-HC column thermostated at 30°C. Organic acids and inorganic anions were detected with a suppressed conductance detector. The precision results showed that the relative standard deviations of the repeatability and reproducibility were <2.94 and <1.37%, respectively. The accuracy of the method was confirmed with an average recovery ranging between 86.3 and 105.6%. Under optimum conditions the detection limits ranged from 0.008 to 0.053 mg/L. The text was submitted by the authors in English.     

Capillary electrophoresis method for analysis of inorganic and organic anions related to habitability and the search for life

In situ missions of exploration require analytical methods that are capable of detecting a wide range of molecular targets in complex matrices without a priori assumptions of sample composition. Furthermore, these methods should minimize the number of reagents needed and any sample preparation steps. We have developed a method for the detection of metabolically relevant inorganic and organic anions that is suitable for implementation on in situ spaceflight missions. Using 55 mM acetic acid, 50 mM triethylamine, and 5% glycerol, more than 21 relevant anions are separated in less than 20 min. The method is robust to sample ionic strength, tolerating high concentrations of background salts (up to 900 mM NaCl and 300 mM MgSO₄). This is an important feature for future missions to ocean worlds. The method was validated using a culture of Escherichia coli and with high salinity natural samples collected from Mono Lake, California.     

Preparation of magnetic molecularly imprinted polymer for the separation of tetracycline antibiotics from egg and tissue samples

Magnetic molecularly imprinted polymers were prepared using hydrophobic Fe₃O₄ magnetite as the magnetically susceptible component, oxytetracycline as template molecule, methacrylic acid as functional monomer, and styrene and divinylbenzene as polymeric matrix components. The polymers were applied to the separation of tetracycline antibiotics from egg and tissue samples. The extraction and clean-up procedures were carried out in a single step by blending and stirring the sample, extraction solvent and polymers. The analytes can be transferred from the sample matrix to the polymers directly or through the extraction solvent as medium. When the extraction was complete, the polymers adsorbing the analytes were easily separated from the sample matrix by an adscititious magnet. The analytes eluted from the polymers were determined by liquid chromatography–tandem mass spectrometry. The recoveries ranging from 72.8% to 96.5% were obtained with relative standard deviations in the range of 2.9–12.3%. The limit of detection was less than 0.2 ng g⁻¹. The feasibility of this method was validated by analysis of incurred egg and tissue samples, and the results were compared with those obtained by the classical method in which solvent extraction, centrifugation, and subsequent clean-up and concentration by solid-phase extraction were applied. The proposed method reduced the complicacy of classical method and improved the reliability of method.     

Extraction and isolation of diphenylheptanes and flavonoids from Alpinia officinarum Hance using supercritical fluid extraction followed by supercritical fluid chromatography

In this paper, an off-line combination method of supercritical fluid extraction and supercritical fluid chromatography was developed for the selective extraction and isolation of diphenylheptanes and flavonoids from Alpinia officinarum Hance. The enrichment of target components was successfully achieved using supercritical fluid extraction with the following conditions (8% ethanol as co-solvent at 45°C and 30 MPa for 30 min). Taking full advantage of the complementarity of supercritical fluid chromatography stationary phases, a two-step preparative supercritical fluid chromatography strategy was constructed. The extract was firstly divided into seven fractions on a Diol column (250 × 20 mm internal diameter, 10 μm) within 8 min by gradient elution increasing from 5% to 20% modifier (methanol) at 55 ml/min and 15 MPa. Then the seven fractions were separated by using a 1-AA or a DEA column (250 × 19 mm internal diameter, 5 μm) at 50 ml/min and 13.5 MPa. This two-step strategy showed superior separation ability for structural analogs. As a result, seven compounds, including four diphenylheptanes and three flavonoids with high purity, were successfully obtained. The developed method is also helpful for the extraction and isolation of other structural analogs of traditional Chinese medicines.     

Fast and selective extraction of nicotine from human plasma based on magnetic strong cation exchange resin followed by liquid chromatography-tandem mass spectrometry

In the study, a fast and selective method based on magnetic separation has been developed for the extraction of nicotine from human plasma using magnetic strong cation exchange (MSCX) resins as adsorbent. MSCX resins were prepared using hydrophobic Fe₃O₄ magnetite as magnetically susceptible component, styrene and acrylic acid as polymeric matrix components, and acetyl sulfonate as the sulfonation agent. The extraction procedure was carried out in a single step by stirring the mixture of diluted plasma sample and MSCX resins in the vortex for 5 min. Then, the resins with adsorbed nicotine were separated from the sample matrix by applying an appropriate magnetic field. Main factors affecting the extraction of nicotine such as the amount of MSCX resins, pH value of the extraction solvent, extraction time, and washing and eluting conditions were optimized. The nicotine eluted from the resins was determined by liquid chromatography–tandem mass spectrometry. The calibration curve obtained by analyzing matrix-matched standards shows excellent linear relationship (r ² = 0.9998) in the concentration range of 10–2,500 ng mL⁻¹. The limit of detection and quantification obtained are 2.9 and 9.7 ng mL⁻¹, respectively. The relative standard deviations of intra- and inter-day obtained are in the range of 1.9–6.9% and 2.5–7.8% with the recoveries ranging from 78.7% to 99.1%. The proposed method was successfully applied to determine nicotine in human plasma phlebotomized from ten male smokers. Nicotine was detectable with the contents ranging from 44.4 to 221.9 ng mL⁻¹ in five samples.