Determination of lead in the urine of exposed and unexposed adults by extraction and flow-injection/atomic absorption spectrometry

Lead is extracted from urine with ammonium pyrrolidien dithiocrbamate into methyl isobutyl ketone, and 20 μl of the extract is injected into a water carrier stream in a flow-injection/atomic absorption system. The procedure is simple, quick, accurate and reproducible. Recoveries are 96–105%. The mean urine lead contents of 20 unexposed and 20 printing-press lead exposed workers was found to be 39.0 ± 8.3 and 71.7 ± 26.3 μg Pb l^?1, respectively.     

Gas chromatography – inductively coupled plasma – time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples

The application of inductively coupled plasma – time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental waters is described. Construction of the transfer line was achieved by means of a relatively simple and rapid coupling procedure. Derivatization of the ionic lead species was achieved by in-situ propylation with sodium tetrapropylborate; simultaneous extraction of the derivatized compounds in hexane was followed by separation and detection by capillary gas chromatography hyphenated to inductively coupled plasma–time-of-flight mass spectrometry. Detection limits for the different organolead species ranged from 10 to 15 fg (as Pb), corresponding to procedural detection limits between 50 and 75 ng L^–1, on the basis of a 50 mL snow sample, extraction with 200 μL hexane, and subsequent injection of 1 μL of the organic extract on to the column. The accuracy of the system was confirmed by additional analysis of the water samples by capillary gas chromatography coupled with microwave-induced plasma–atomic-emission spectrometry and the analysis of a standard reference material CRM 605 (road dust) with a certified content of trimethyllead.     

用水溶性四苯基乙烯基荧光探针检测ctDNA

设计合成了一种水溶性的四苯基乙烯(TPE)衍生物TPEDPyMe,研究了该化合物的吸收和发射特性,发现TPEDPyMe具有聚集诱导发光(AIE)性能.在pH值为7.2的三羟甲基氨基甲烷-盐酸(tris-HCl)缓冲溶液中用TPEDPyMe检测小牛胸腺DNA(ctDNA)时观察到,随着ctDNA的浓度从0μg/mL增大到...     

Development of a continuous flow hydride generation laser-induced breakdown spectroscopic system: Determination of tin in aqueous environments

The design, construction and optimization studies of a continuous flow hydride generation laser-induced breakdown spectroscopic system, HG-LIBS, for the determination of tin in aqueous environments is presented. Optimization of the Laser Induced Breakdown Spectroscopy (LIBS) signal with respect to carrier gas flow rate, analyte, acid (HCl) and reductant (NaBH₄) concentrations and flow rates was performed by using spectral emission intensity from the neutral Sn(I) line at 284.0 nm under atmospheric pressures. With flow rates of 5.0 mL/min for NaBH₄ and 2.5 mL/min for HCl, optimum NaBH₄ and HCl concentrations were determined as 2.0% (w/v) and 1.0% (v/v), respectively. The hydride generation efficiency of the system was tested for tin hydride, stannane (SnH₄), by inductively coupled plasma mass spectrometer (ICP-MS). It was found that higher than 99% of the analyte was released into the gaseous phase. Upon optimization, the minimum detectable Sn concentration was found as 0.3 mg/L in water samples. That corresponds to more than two orders of increase in sensitivity compared to methods that employ common sample introduction techniques in liquids analysis by LIBS. Over 90% recoveries were obtained from spiking experiments with river, tap and drinking water samples. Results illustrate potential use of the continuous flow HG-LIBS system for monitoring of Sn concentrations in aqueous environments.     

Determination of tamarixetin and kaempferide in rat plasma and urine by high-performance liquid chromatography

Tamarixetin and kaempferide, the major bioactive constituents of Xiheliu extract, have been simultaneously/quantitatively determined in rat plasma and urine by a sensitive high performance liquid chromatography method after oral administration the total flavonoids from Xiheliu. In this study, the biological samples were prepared by solid-phase extraction, then simultaneously detected at 254 nm and successfully separated and quantified using a reversed-phase C₁₈ column with methanol-formic acid aqueous gradient solution, at a flow rate of 1 mL/min. Good linearity (r > 0.989) of tamarixetin was observed in plasma and urine with the calibration ranges both at 1.6–80 μg/mL. For kaempferide, the correlation coefficient reached 0.994 in plasma at 1.4–70 μg/mL. The RSD of intra- and inter-day were 1.9–6.5% for tamarixetin and 1.3–9.0% for kaempferide in plasma; in urine, the intra- and inter-day RSD for not only tamarixetin but also kaempferide was no more than 7.4 and 5.8%, respectively. The lowest extraction recovery was 87.6% for kaempferide and 93.2% for tamarixetin in plasma and urine for both low and high concentrations. Due to the high sensitivity (the LOQ for tamarixetin was 1.2 μg/mL and for kaempferide 1.4 μg/mL), accuracy, precision, and good selectivity, the assay was successfully applied to pharmacokinetic studies of both flavonols in rats. The half-lives of tamarixetin and kaempferide were 17.8 ± 1.4 and 92.5 ± 1.6 min, and the c _max were 3.1 ± 0.2 and 2.5 ± 0.4 μg/mL, respectively.     

Hollow‐fiber‐supported liquid membrane microextraction of amlodipine and atorvastatin

A simple, environmentally friendly, and efficient method, based on hollow‐fiber‐supported liquid membrane microextraction, followed by high‐performance liquid chromatography has been developed for the extraction and determination of amlodipine (AML) and atorvastatin (ATO) in water and urine samples. The AML in two‐phase hollow‐fiber liquid microextraction is extracted from 24.0 mL of the aqueous sample into an organic phase with microliter volume located inside the pores and lumen of a polypropylene hollow fiber as acceptor phase, but the ATO in three‐phase hollow‐fiber liquid microextraction is extracted from aqueous donor phase to organic phase and then back‐extracted to the aqueous acceptor phase, which can be directly injected into the high‐performance liquid chromatograph for analysis. The preconcentration factors in a range of 34–135 were obtained under the optimum conditions. The calibration curves were linear (R² ≥ 0.990) in the concentration range of 2.0–200 μg/L for AML and 5.0–200 μg/L for ATO. The limits of detection for AML and ATO were 0.5 and 2.0 μg/L, respectively. Tap water and human urine samples were successfully analyzed for the existence of AML and ATO using the proposed methods.     

ICP-AES法测定锡精矿中锡、铜、铅、铁的含量

建立了过氧化钠熔融分解样品、电感耦合等离子发射光谱法（ICP-AES）测定锡精矿中锡、铜、铅、铁的新方法。对试样分解方法、过氧化钠用量、元素分析谱线等进行了讨论。选择过氧化钠用量为2．0g,样品熔融温度为850~C,锡、铜、铅、铁分析谱线分别为189．991,324．754,220．353,259．940nm。将该方法应用于标准样品（BY0107—1）中Sn,Cu,Pb,Fe的测定,待测元素的回收率在92．0％-101．6％之间,检出限为分别为0．006,0．002,0．005,0．001μg／mL,测定结果的相对标准偏差为0．16％～2．11％（n=5）。     

Determination of tin and lead in sediment slurries by graphite furnace atomic absorption spectrometry

Methods were determined for lead and tin determinations in river, marine and lake sediments by slurry sampling and graphite furnace atomic absorption spectrometry. The optimizations were carried out using River Sediment BCR 320 and Marine Sediment PACS-2 for Pb and Sn, respectively. For Pb determination, the parameters studied included inorganic acid mixture, stabilizing agent, sample mass and sonication time. The influence of diluents and the extraction to the liquid phase for two different matrices was evaluated for Sn. The Pb content in the slurry liquid phase was ca. 56%, and ranged from 75% to 100% for Sn. Representative masses of 34 and 45 mg, and effective masses of 12 and 48 μg for Pb and Sn, respectively, were obtained under optimized conditions. Detection and quantification limits of 0.2 and 0.7 μg g⁻¹ for Pb, and 1.5–2.6 and 4.5–7.6 μg g⁻¹ for Sn were obtained.

     

Speciation of mercury,tin, and lead compounds by gas chromatography with microwave-induced plasma and atomic-emission detection (GC–MIP–AED)

Because of their high toxicity and widespread distribution, the reliable selective quantification of alkyl and aryl species containing mercury, tin, or lead has been one of the goals of speciation analysis in recent years. Since becoming commercially available, GC-MIP-AED has been one of the most-used tools in this work. In this paper, the value and limitations of GC-MIP-AED for the speciation of Hg, Sn, and Pb compounds in environmental samples are reviewed and compared with the analytical characteristics of other hyphenated GC-based techniques. Because quantification of Hg, Sn, and Pb species by GC techniques normally requires complex sample preparation involving several steps, the effect of sample-preparation methods on the accuracy and precision of the results is discussed. Finally, we describe the current status of a rapid, low-cost GC-MIP-PED system specifically designed for routine quantification of Hg, Sn, and Pb species in environmental control laboratories.     

高效液相色谱-荧光分析法同时测定人体尿液中黄蝶呤与异黄蝶呤

建立了高效液相色谱-荧光法同时测定癌症病人尿液中黄蝶呤及异黄蝶呤的新方法。选择荧光检测波长λex=345nm,λem=420nm。以磷酸盐缓冲溶液(pH=7.5)-甲醇(体积比为98∶2)为流动相,流速1.0mL/min,黄蝶呤与异黄蝶呤含量分别在0.0013～0.945μg/mL及0.00017～0.118μg/mL范围内与色谱峰面积呈良好的线性关系,线性相关系数分别为0.9999和0.9996,检出限分别为0.5ng/mL和0.05ng/mL,加标平均回收率在86.2%～107.5%之间。方法应用于癌症病人尿样分析,取得了较好的结果。     

Extraktions-spektrophotometrische Bestimmung von Zinn in Fein- und Hüttenblei

A method suitable for the determination of 0.001–0.2% of tin in lead is described. Quadrivalent tin is extracted from the sample solution (6–8 N in hydrochloric acid) by a solution of Amberlite LA-2 in xylene and back-extracted into the aqueous phase by dilute nitric acid. After evaporation of the acidic extract and destruction of the organic matter tin is determined in the residue by Lukes method with 9-phenylfluorone as reagent.     

微波消解样品-电感耦合等离子体原子发射光谱法测定铅精矿中铅、砷、镉、汞

采用微波消解样品-电感耦合等离子体原子发射光谱法同时测定铅精矿中主体元素铅及有毒有害元素砷、镉、汞的含量。0.20g试样置于消解罐中,先后加入硝酸9mL、盐酸3mL、氟硼酸2mL及过氧化氢2.5mL,密闭罐盖按设定的微波消解程序进行消解。试验选择铅、砷、镉和汞的分析线分别为220.351,189.042,228.802,184.950nm以消除基体干扰。铅、砷、镉、汞的检出限分别为16.0,2.2,0.4,0.8μg.g-1。方法用于铅精矿标准样品(GBW 07617)和铅精矿实际样品分析,此方法的测定值与认定值及原子吸收光谱法或原子荧光光谱法的测定值相一致。方法的相对标准偏差(n=10)在0.15%～3.9%之间。     

Preconcentration and determination of trace amounts of lead (II) as thenoyltrifluoroacetone complex with dibenzo-18-crown-6 by synergistic extraction and atomic absorption spectrometry

A new method for the preconcentration and determination of trace amounts of lead at the μg/L level in natural waters has been established based on the formation of the thenoyltrifluoroacetone (TTA) complex with dibenzo-18-crown-6 (DB18C6) by means of synergistic extraction and back-extraction combined with atomic absorption spectrometry (AAS). The effect of various factors (synergism with TTA and DB18C6, shaking time, preconcentration factor, composition of the extracted species, and foreign ions etc.) on the extraction and back-extraction of lead has been investigated in detail. The lead-TTA chelate in o-dichlorobenzene forms a stable adduct with DB18C6 as Pb(TTA)₂ DB18C6. The stability constant (β) of the adduct determined by curve fitting method was log β = 4.2. The amount of lead in natural waters such as tap water (Kanazawa University) and Kakehashi river (Komatsu City) determined by the present method was found to be 0.64 ± 0.02 μg/L and 5.10 ± 0.03 μg/L, respectively.     

Water‐compatible molecularly imprinted polymer as a sorbent for the selective extraction and purification of adefovir from human serum and urine

A molecularly imprinted polymer has been synthesized to specifically extract adefovir, an antiviral drug, from serum and urine by dispersive solid‐phase extraction before high‐performance liquid chromatography with UV analysis. The imprinted polymers were prepared by bulk polymerization by a noncovalent imprinting method that involved the use of adefovir (template molecule) and functional monomer (methacrylic acid) complex prior to polymerization, ethylene glycol dimethacrylate as cross‐linker, and chloroform as porogen. Molecular recognition properties, binding capacity, and selectivity of the molecularly imprinted polymers were evaluated and the results show that the obtained polymers have high specific retention and enrichment for adefovir in aqueous medium. The new imprinted polymer was utilized as a molecular sorbent for the separation of adefovir from human serum and urine. The serum and urine extraction of adefovir by the molecularly imprinted polymer followed by high‐performance liquid chromatography showed a linear calibration curve in the range of 20–100 μg/L with excellent precisions (2.5 and 2.8% for 50 μg/L), respectively. The limit of detection and limit of quantization were determined in serum (7.62 and 15.1 μg/L), and urine (5.45 and 16 μg/L). The recoveries for serum and urine samples were found to be 88.2–93.5 and 84.3–90.2%, respectively.     

Rhodium as permanent modifier for atomization of lead from biological fluids using tungsten filament electrothermal atomic absorption spectrometry

Rhodium (Rh) was investigated as a permanent modifier for the atomization of Pb from biological fluids in W-filament atomic absorption spectrometry (AAS). Heating the W-filament with a Rh solution provided a protective coating for subsequent determinations of Pb in blood and urine matrices. The W-filament AAS instrumentation used was based on a prototype design that utilized self-reversal background correction scheme and peak area measurements. We found that Rh not only stabilized Pb during the pyrolysis step, but also facilitated the removal of carbonaceous residues during the cleaning step, requiring much less power than with phosphate modifier. Thus, the filament lifetime was greatly extended to over 300 firings. Periodic reconditioning with Rh was necessary every 30 firings or so. Conditioning the filament with Rh also permitted direct calibration using simple aqueous Pb standards. The method detection limit for blood Pb was approximately 1.5 μg dl⁻¹, similar to that reported previously. Potential interferences from concomitants such as Na, K, Ca and Mg were evaluated. Accuracy was verified using lead reference materials from the National Institute of Standards and Technology and the New York State Department of Health. Blood lead results below 40 μg dl⁻¹ were within ±1 μg dl⁻¹ of certified values, and within ±10% above 40 μg dl⁻¹; within-run precision was ±10% or better. Additional validation was reported using proficiency test materials and human blood specimens. All blood lead results were within the acceptable limits established by regulatory authorities in the US. When measuring Pb in urine, sensitivity was reduced and matrix-matched calibration became necessary. The method of detection limit was 27 μg l⁻¹ for urine Pb. Urine lead results were also validated using an acceptable range comparable to that established for blood lead by US regulatory agencies.     

顺序注射氢化物发生-原子荧光光谱法同时测定中草药中的铅和锡

建立了一种顺序注射氢化物发生一原子荧光光谱法同时测定中草药中的铅和锡含量的方法,同时讨论了共存离子的干扰情况。结果表明,在最佳实验条件下,铅和锡的检出限分别为0．0253μg／L和0．0425μg／L,加标回收率为95．5％～103．1％,相对标准偏差小于5．2％,被测试样中共存的离子对铅和锡的测定没有干扰。该法操作方便、快速,用于中草药试样中铅和锡的同时测定,具有很好的可行性和实用性。     

Transmethylation of metals in aquatic systems

Transmethylation reactions between organometals and metal ions in aqueous solutions in biotic and abiotic systems, with and without the presence of sediment, were investigated. It was found that alkyllead compounds can transfer their alkyl groups to Sn(II) and Sn(IV) ions to form various methyltin compounds in biotic and abiotic systems. The presence of sediment enhanced the transmethylation reactions. Methyltin compounds do not transfer their methyl groups of Pb(II). Methylarsenic acids transfer their methyl groups to Sn(II) and Sn(IV) in an abiotic system, but not in a biotic system containing sediment. The strong adsorption of tin onto sediment was the reason for the non-availability of tin ions for methylation. Methylarsenic acids do not transmethylate Pb(II). Other alkyllead compounds, such as ethyllead and butyllead species were also able to transfer their alkyl groups to tin. When both trimethyllead and triethyllead species are present in the same system, only the individual monoalkyl tin species were formed in both the Sn(II) and Sn(IV) solutions. No mixed alkyltin was produced. The findings of this study suggest that alkyllead compounds, if present in the environment, could be potential methylating agents for the formation of other methylmetals, such as methyltins. Methyltin compounds have already been documented to methylate mercuric ions in aqueous solution. Thus the study of transmethylation reactions opens up a new area of research that is essential in predicting the fate of organometals in the environment.     

Electrochemiluminescence determination of heavy metals in aqueous solutions using a wall-jet detector

The use of a wall-jet detector for determining heavy metals by their intrinsic electrochemiluminescence at an aluminum electrode is described. The possibility of rapidly determining tin, lead, mercury, and thallium with detection limits from 1 μg/L for Pb(II) to 5 ng/L for Hg(II) by the intensity of luminescence that appears during cathodic pulses is demonstrated.     

Simultaneous determination of heavy metals in waters by inductively-coupled plasma atomic emission spectrometry after extraction into diisobutyl ketone

Nebulization of more than thirty aliphatic and aromatic liquids into a low power (<1.6 kW) argon inductively-coupled plasma (i.c.p.) was evaluated. Diisobutyl ketone (DIBK) was best owing to the ease of its introduction into the i.c.p. and low aqueous solubility. Dichloro-8-quinolinol, hexamethyleneammonium hexamethylenedithiocarbamate and ammonium pyrrolidinedithiocarbamate were tested for extraction ; the last was preferred as chelating reagent because it formed complexes with Cd, Pb, Zn, Fe, Cu, Ni, Mo and V at pH 2.4. These metals at μg l^-1 levels in river and sea water were extracted into DIBK and determined simultaneously by i.c.p. atomic emission spectrometry. The optimum observation height for the DIBK extract was higher than that for an aqueous solution.     

Evaluation of a tungsten coil atomization-laser-induced fluorescence detection approach for trace elemental analysis

The analytical utility of a tungsten (W)-coil atomization-laser-induced fluorescence (LIF) approach has been evaluated for trace level measurements of elemental chromium (Cr), arsenic (As), selenium (Se), antimony (Sb), lead (Pb), tin (Sn), copper (Cu), thallium (Tl), indium (In), cadmium (Cd), zinc (Zn) and mercury (Hg). Measurements of As, Cr, In, Se, Sb, Pb, Tl, and Sn were performed by laser-induced fluorescence using a single dye laser operating near 460 nm whose output was converted by frequency doubling and stimulated Raman scattering to wavelengths ranging from 196 to 286 nm for atomic excitation. Absolute limits of detection (LODs) of 1, 0.3, 0.3, 0.2, 1, 6, 1, 0.2 and 0.8 pg and concentration LODs of 100, 30, 30, 20, 100, 600, 100, 20, and 80 pg/mL were achieved for As, Se, Sb, Sn, In, Cu, Cr, Pb and Tl, respectively. Determinations of Hg, Pb, Zn and Cd were performed using two-color excitation approaches and resulted in absolute LODs of 2, 30, 5 and 0.6 pg, respectively, and concentration LODs of 200, 3000, 500 and 60 pg/mL, respectively. The sensitivities achieved by the W-coil LIF approaches compare well with those reported by W-coil atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and graphite furnace electrothermal atomization-LIF approaches. The accuracy of the approach was verified through the analysis of a multielement reference solution containing Sb, Pb and Tl which each had certified performance acceptance limits of 19.6-20.4 μg/mL. The determined concentrations were 20.05 ± 2.60, 20.70 ± 2.27 and 20.60 ± 2.46 μg/mL, for Sb, Pb and Tl, respectively. The results demonstrate that W-coil LIF provides good analytical performance for trace analyses due to its high sensitivity, linearity, and capability to measure multiple elements using a single tunable laser and suggest that the development of portable W-coil LIF instrumentation using compact, solid-state lasers is feasible.