Analytical performance of a multi-element ICP-AES method for Cd, Co, Cr, Cu, Mn, Ni and Pb determination in blood fraction samples

An analytical method using inductively coupled plasma atomic emission spectrometry (ICP-AES) for rapid simultaneous determination of seven heavy metals (Cd, Co, Cr, Cu, Mn, Ni and Pb) in human blood fractions, like plasma, cells fraction and whole blood, is performed. The optimum wavelength was selected using as criterions the sensitivity, the linearity and recovery of aqueous standard solutions. The pretreatment of the sample, the centrifugal conditions, the necessity of digestion and the dilution of the digests were also studied. For plasma it was possible to avoid digestion of the sample, but for cells fractions and whole blood the digestion is necessary. The samples were acid-digested by HNO₃ in closed Teflon tubes under high temperature and pressure conditions and were diluted before injection into ICP-AES. Also, optimization of the inductively coupled plasma conditions like nebulizer argon flow rate, sample flow rate and power of radio frequency was performed for each analyte. Finally, the effect of the type of the employed calibration technique on the total variation of the method was examined. Calibration using the standard addition technique was proved more accurate for the determination in terms of analyte recovery. The sensitivity and recovery (Cd 99%, Co 101%, Cr 100%, Cu 99%, Mn 101%, Ni 100% and Pb 97%) of the developed method are presented for all examined blood fractions. Correspondence: George A. Zachariadis, Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, Thessaloniki 54124, Greece     

Plasma deposition of thin films from a fluorine-containing cyclosiloxane

Thin films have been deposited from radio-frequency glow discharges fed with vapors of a silicon- and fluorine-containing organic compound, namely 2,4,6-tris[(3,3,3-trifluoropropyl) (methyl)] cyclotrisiloxane, in mixture with argon. 2,4,6-tris[(3,3,3-trifluoropropyl)(methyl)]cyclotrisiloxane A triode reactor has been utilized to deposit films by independently changing substrate temperature and bias-induced ion-bombardment. Laser interferometry, electron spectroscopy for chemical analysis and Fourier-transform infrared spectroscopy have been used to monitor film growth rate and composition. Results unambiguously show an activating effect of the ion-bombardment, which confirm the validity of the ion-assisted deposition model utilized for the plasma deposition of both teflon- and silicone-like films. In our experiments, low substrate temperature and bias conditions results in films with a “monomer-like” stoichiometry, while drastic conditions give origin to materials with a completely different composition and a markedly increased hardness. © 1994 John Wiley & Sons, Inc.     

Comparison of plasma pharmacokinetics of Tanreqing solution between intratracheal aerosolization and intravenous injection in rats

A rapid ultra high performance liquid chromatography tandem mass spectrometry method was developed for the simultaneous analysis of baicalin, oroxylin A‐7‐O‐β‐d ‐glucoronide and chlorogenic acid in rats plasma, and applied to comparison of pharmacokinetics of Tanreqing solution between intratracheal aerosolization and intravenous injection. Results of the analytical method validation assay showed high sensitivity, accuracy and suitable recovery. Results of pharmacokinetics showed similar decline phases for baicalin, oroxylin A‐7‐O‐β‐d ‐glucoronide and chlorogenic acid in two different delivery routes. The half‐lives of intratracheal aerosolization and intravenous injection were 0.90 and 1.22 h for baicalin, 0.47 and 0.17 h for oroxylin A‐7‐O‐β‐d ‐glucoronide and 0.22 and 0.13 h for chlorogenic acid, and this implies that compounds were retained in the lung for a relatively short time. This study was the first to provide important pharmacokinetics information for traditional Chinese medicine delivery to the lung.     

Spatially and time-resolved element-specific in situ corrosion investigations with an online hyphenated microcapillary flow injection inductively coupled plasma mass spectrometry set-up

A novel technique for in situ spatial, time-resolved element-specific investigations of corrosion processes is developed. The technique is based on an online hyphenation of a specially designed microflow-capillary set-up to inductively coupled plasma mass spectrometry (ICP-MS) using flow injection sample introduction. Detailed aspects of the method development, optimization of the sample microflow introduction and flow injection characteristics for the localized corrosion analysis are described. Moreover, specific challenges of the ICP-MS analysis as applied to the analysis of corrosion sample probes, e.g. high matrix load and limited sample volume, are discussed.     

Simultaneous determination of rosiglitazone and metformin in plasma by gradient liquid chromatography with UV detection

A novel, fast and simple liquid chromatographic method was developed and validated for the simultaneous determination of rosiglitazone and metformin in human plasma. The analysis was performed on a phenyl column (250 mm × 4.6 mm i.d., 5 μm) using a gradient method starting with mobile phase composed of acetonitrile:5 mM acetate buffer pH 5.5 (75:25, v/v). The flow rate was 1 mL min⁻¹. UV detection was performed at 245 nm and verapamil was used as internal standard. The total run time was less than 10 min. Sample preparation included a simple protein precipitation step with acetonitrile. Validation experiments were performed to demonstrate stability, specificity, sensitivity, linearity, accuracy, precision and robustness. The limit of quantification was 100 ng mL⁻¹ for rosiglitazone and 250 ng mL⁻¹ for metformin. The extraction recoveries were 100.02-105.0% for rosiglitazone and 105.64-103.88% for metformin. The method was applied with success to plasma samples obtained from diabetic patients undergoing treatment with rosiglitazone and metformin.     

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

We report the charge state distributions of the pure, 25% and 50% oxygen mixed krypton plasma to shed more light on the understanding of the gas mixing and the isotope anomaly [A. G. Drentje, Rev. Sci. Instrum. 63 (1992) 2875 and Y Kawai, D Meyer, A Nadzeyka, U Wolters and K Wiesemann, Plasma Sources Sci. Technol. 10 (2001) 451] in the electron cyclotron resonance (ECR) plasmas. The krypton plasma was produced using a 10 GHz all‐permanent‐magnet ECR ion source. The intensities of the highly abundant four isotopes, viz. ⁸²Kr (~11.58%), ⁸³Kr (~11.49%), ⁸⁴Kr (~57%) and ⁸⁶Kr (17.3%) up to ~ +14 charge state have been measured by extracting the ions from the plasma and analysing them in the mass and the energy using a large acceptance analyzer‐cum‐switching dipole magnet. The influence of the oxygen gas mixing on the isotopic krypton ion intensities is clearly evidenced beyond +9 charge state. With and without oxygen mixing, the charge state distribution of the krypton ECR plasma shows the isotope anomaly with unusual trends. The anomaly in the intensities of the isotopes having quite closer natural abundance, viz. ⁸²Kr, ⁸⁶Kr and ⁸³Kr, ⁸⁶Kr is prominent, whereas the intensity ratio of ⁸⁶Kr to ⁸⁴Kr shows a weak signature of it. The isotope anomaly tends to disappear with increasing oxygen mixing in the plasma. The observed trends in the intensities of the krypton isotopes do not follow the prediction of linear Landau wave damping in the plasma. Copyright © 2016 John Wiley & Sons, Ltd.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定锡精矿中8种杂质元素

应用电感耦合等离子体原子发射光谱(ICP-AES)法同时测定锡精矿中钙、镁、铜、铅、锌、砷、锑、铋8种杂质元素。对锡精矿样品的分解方法进行了合理选择,并对测定时的元素分析谱线、基体及各测定元素间干扰情况等进行了讨论。采用硝酸、盐酸、氢氟酸、高氯酸溶样,盐酸浸取。基体效应较小,各待测元素之间基本无干扰。测定结果与国家标准方法比对结果基本一致,相对标准偏差为1.3%~3.3%(n=11),方法加标回收率为96.0%~105%,能满足实际工作中准确、高效地分析锡精矿中杂质元素的需要。     

A simple LC‐MS method for determination of cyasterone in rat plasma: application to a pilot pharmacokinetic study

A simple, specific, and sensitive liquid chromatography–mass spectrometry (LC‐MS) method for determination of cyasterone in rat plasma was developed in our laboratory. Cucurbitacin B was used as an internal standard (IS). After protein precipitation with twofold volume of acetonitrile, the analyte and IS were separated on a Luna C₁₈ column (100 × 4.6 mm, i.d., 3.0 µm; Phenomenex) by isocratic elution with acetonitrile–water (80:20, v/v) as the mobile phase at a flow rate of 0.4 mL/min. An electrospray ionization source was applied and operated in the positive ion mode; selected ion monitoring scan mode was used for quantification, and the target ions m/z 543.3 for cyasterone and m/z 581.3 for IS were chosen. Good linearity was observed in the concentration range of 0.40–400 ng/mL for cyasterone in rat plasma. Intra‐day and inter‐day precision were both <7.4%. This method was proved to be suitable for pharmacokinetic studies after oral (5.0 mg/kg) or intravenous (0.5 mg/kg) administration of cyasterone in rats. Copyright © 2015 John Wiley & Sons, Ltd.     

Application of LC/MS and ICP/MS for establishing the fingerprint spectrum of the traditional Chinese medicinal preparation Gan-Lu-Yin

We developed a method to analyze the fingerprint spectrum qualitatively and quantitatively for the traditional Chinese herbal medicinal preparation Gan-Lu-Yin with HPLC combined with photodiode array detection, and MS, and to identify the preparation's 14 main components including baicalin, baicalein, oroxylin A-7-O-glucuronide, wogonin-7-O-glucuronide, wogonin, and oroxylin A in Radix Scutellariae; naringin and neohesperidin in Aurantii fructus; liquiritigenin, liquiritin, and glycyrrhizic acid in Radix Glycyrrhizae. In LC/UV assay, a Cosmosil 5C18-MS-II column was used as the stationary phase, and a gradient of potassium dihydrogen phosphate, ACN, and water as the elute solution. The UV detection wavelengths were 250 and 280 nm. In LC/MS assay, a gradient of phosphoric acid, ACN, and water was used as the elute solution, and electrospray positive ion mode ((+)-ESI) as the analytic mode. In order to explore the distribution of trace metal elements effectively in Gan-Lu-Yin, a microwave digestion method was used for sample treatment, and an inductively coupled plasma MS assay was used to analyze fingerprint spectra of the inorganic metals in Gan-Lu-Yin. Combined with fingerprint spectra of organic compounds by LC/UV and LC/MS, it was expected to provide effective quality control in the production of Gan-Lu-Yin.     

Quantification and pharmacokinetic property of verubecestat an BACE1 inhibitor in rat plasma

In the present study, an ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) approach was designed to measure the rat plasma levels of verubecestat with diazepam as the internal standard. Acetonitrile-based protein precipitation was applied for sample preparation, then the analyte verubecestat was subjected to gradient elution chromatography with a mobile phase composed of acetonitrile (A) and 0.1% formic acid in water (B). Verubecestat was monitored by m/z 410.1 → 124.0 transition for quantification by multiple reaction monitoring (MRM) in positive ion electrospray ionization (ESI) source. When the concentration of verubecestat ranged from 1 to 2500 ng/mL, the method exhibited good linearity. For verubecestat, the intra- and inter-day precision were determined with the values of 2.9–9.0% and 0.4–6.5%, respectively; and the accuracy ranged from −2.2% to 10.4%. Matrix effect, extraction recovery, and stability data were in line with the standard FDA guidelines for validating a bioanalytical method. The validity of the developed method was confirmed through the pharmacokinetic study.