A new approach for determination of crustal and trace elements in airborne particulate matter

An ICP-OES procedure was developed for fast and accurate determination of various crustal (Al, Ca, Fe, Mg, Si) and trace elements (Ba, Cu, Mn, Na, K, Sr, Ti, Zn) in airborne particulate matter. The method is based on a preliminary treatment of the aerosol samples with a mixture of nitric acid and hydrogen peroxide at elevated temperature leading to a mineralization of the organic sampling substrate, dissolution of soluble material and homogeneous suspension of the remaining non-soluble fraction. After dilution the derived slurry solutions were measured using ICP-OES. The reproducibility of analysis given as the relative standard deviation (% RSD) varied between 3.2 and 6.8% for bulk constituents such as Al, Ca, Fe, Mg and Si whereas values ranging from 3.5 to 9.1% were obtained for trace metals present with distinctly lower abundance in PM10 (e.g. Ba, Cu, Mn, Sr, Zn). The limits of detection (LOD) calculated as three times the standard deviation (3σ) of the signal derived from filter blank samples ranged from approximately 1?ng?m^?3 (Sr) to 71?ng?m^?3(Ca). The developed procedure was evaluated by comparing the obtained results with the findings derived for the same set of aerosol samples analyzed using a microwave procedure for sample dissolution with subsequent ICP-OES analysis. Finally the developed procedure was applied for the analysis of crustal and trace elements in PM10 samples collected at an urban site (Getreidemarkt, Vienna) and a rural site (Hartberg, Styria), in Austria. The concentrations of the investigated crustal elements varied between some hundred ng?m^?3 and few µg?m^?3 with highest concentrations for Fe and Si, distinctly reduced concentrations ranging from some ng?m^?3 (Sr) to more than hundred ng?m^?3 (K) were found for trace elements. Observed PM10 concentrations were found to be in accordance to literature findings from urban sites in central Europe.     

High-performance anion-exchange chromatography–mass spectrometry method for determination of levoglucosan, mannosan, and galactosan in atmospheric fine particulate matter

Biomass burning has a strong influence on the atmospheric aerosol composition through particulate organic, inorganic, and soot emissions. When biomass burns, cellulose and hemicelluloses degrade, producing monosaccharide anhydrides (MAs) such as levoglucosan, mannosan, and galactosan. Therefore, these compounds have been commonly used as tracers for biomass burning. In this study, a fast water-based method was developed for the routine analysis of MAs, based on high-performance anion-exchange chromatography with electrospray ionization mass spectrometry detection. This method combines simple sample preparation, fast separation, and the advantages of the selective detection with MS. Analysis run was optimized to the maximum separation of levoglucosan, mannosan, and galactosan with 15-min analysis. The validation results indicated that the method showed good applicability for determination of MA isomer concentrations in ambient samples. The limit of detection was 100 pg for levoglucosan and 50 pg for mannosan and galactosan. Wide determination ranges enabled the analysis of samples of different concentration levels. The method showed good precision, both for standard solutions (3.9–5.9% RSD) and for fine particle samples (4.3–8.5% RSD). Co-elution of internal standard (carbon-13-labeled levoglucosan) and sugar alcohols with levoglucosan decreased the sensitivity of levoglucosan determination. The method was used to determine the MA concentrations in ambient fine particle samples from urban background (Helsinki) and rural background (Hyytiälä) in Finland. The average levoglucosan, mannosan, and galactosan concentrations were 77, 8.8, and 4.2 ng?m^?3 in Helsinki (winter 2008–2009) and 17, 2.3, and 1.4 ng?m^?3 in Hyytiälä (spring 2007), respectively. The interrelation of the three MA isomers was fairly constant in the ambient fine particle samples.     

The determination of hydrogen chloride in ambient air with diffusion/denuder tubes

A manual method for the determination of hydrogen chloride in air, based on diffusion/denuder tube separation from particulate chloride aerosol is described. When air is drawn through a tube coated with a selective absorbent (sodium fluoride), separation is achieved because gaseous hydrogen chloride diffuses much more rapidly to the tube walls than particulate chloride aerosol, which passes through virtually unabsorbed. After the sampling period (the length of which depends on the concentration of gaseous hydrogen chloride expected), the sorbed hydrogen chloride is washed from the tube and measured with a highly sensitive chloride ion-selective electrode with a mercury (I) chloride membrane. The method is examined theoretically and experimentally. The experimentally derived absorption efficiencies of the diffusion/denuder tubes were > 90% and the standard deviation of the method was 0.023 μg m^?3 for hydrogen chloride concentrations of 0.16–0.55 μg m^?3. Interference from particulate chloride salts was negligible; this was confirmed by tests with artificially generated aerosol particles from an aerosol generator. The diffusion/denuder tubes have high capacity; level as high as 330 μg m^?3 hydrogen chloride can be sampled for 60 min without affecting performance. A detection limit of (50/t) μg m^?3 can be achieved, where t is the sampling rime (min); e.g., 1μg m^?3 hydrogen chloride can be detected with a sampling period of 50 min.     

Determination of ultra-trace levels of cobalt by ion chromatographic separation and chemiluminescence detection

A luminol chemiluminescence detection/flow injection analysis technique coupled with ion chromatography (IC) has been examined for the selective determination of cobalt (II) at pg ml^?1 levels. A barium chloride solution was used as an eluent in the IC to separate cobalt(II) from interferents. When a 100-μ1 sample injection volume was used, the detection limit was 1.0 pg ml^?1 cobalt; the minimum detectable amount of cobalt was 100 fg. The calibration graph was linear above 10 pg ml^?1 and the linear dynamic range extended over six orders of magnitude. The relative standard deviation for ten replicate measurements of 30 pg ml^?1 cobalt was 3.8%. The results of the analysis of a synthetic sample corresponding to a boiling-water reactor coolant and some commercially available copper(II) standard solutions are given.     

Evolution of anthropogenic aerosols in the coastal town of Salina Cruz,Mexico: part III size-segregated elemental composition analysed by total-reflection X-ray fluorescence spectrometry

Heavy metals in various size modes of the atmospheric aerosol are a concern for human health. Their and other elements’ concentrations are indicative for anthropogenic and natural aerosol sources. Si, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Hg, and Pb were determined as a complementary contribution to a study on aerosol cycling during the wet season, June 2004, in a humid, subtropical climate, i.e. in the city of Salina Cruz, situated on the Pacific coast of the Isthmus of Tehuantepec (16.2°N, 95.2°W), Mexico. For mass (gravimetry) and elemental analyses, particles were collected by a Berner low-pressure round nozzle cascade impactor using four stages corresponding to 0.1–0.25, 0.25–1.0, 1.0–4.0, and 4–16?µm of aerodynamic particle size. The impaction plates were modified such that approx. 1/6 consisted of a plastic support (Persplex®) for total reflection X-ray fluorescence spectrometry (TXRF). The elements’ total content was determined by TXRF without any further sample pretreatment. Limits of quantification (LOQ) for elemental content in individual impactor stages corresponded to 25–60?ng?m^?3 for Si; 0.8–4?ng?m^?3 for Cl, K, Ca, Ti, and V; 3–20?pg?m^?3 for Cr, Mn, Fe, Cu, Ni, and Zn; and 7–50?pg?m^?3 for As, Se, Br, Rb, Sr, Hg, and Pb. In some samples, however, high blank values for the supports gave an LOQ?=?6–19?ng?m^?3 for Cl; 3--7?ng?m^?3 for Ca; 3–7?ng?m^?3 for Fe, Ni, Cu, and Zn; and 60–70?ng?m^?3 for Pb. The influence of local natural, industrial, and vehicle traffic sources for heavy-metal mobilization was obvious. Heavy-metal abundances did not coincide with regionally distributed pollutants. V and Ni were found at particularly elevated levels advected with the sea breeze, which points to ships as sources. Br and Pb were found at particularly low levels. The concentrations of Br, Rb, Sr, and Pb were found below LOQ at least in some, As, Co, Se, and Hg in all of the samples. The elements’ characteristic differences in mass size distributions were obvious despite the coarse size resolution. During the cycling of air masses from land to sea and back again, enrichment of super-micrometre particles in the near ground aerosol was observed under dry weather conditions. Rain preferentially removed the large particles with which heavy metals have been associated.     

Selection of sampling adsorbents and optimisation and validation of a GC-MS/MS method for airborne pesticides

A methodology for the sampling and determination of airborne pesticides has been developed. The trapping efficiency of three adsorbents, namely XAD-2,XAD-4 and a sandwich sorbent (PUF-XAD2-PUF), was tested for 34 pesticides and the latter was selected because it presented the highest retention capacity without breakthrough. Pesticides were determined by gas chromatography coupled to an ion trap mass spectrometer in tandem. The method showed recoveries ranging from 70% to 120% with limits of quantification in the range of 16.1–322.6 pg m^?3 when 155 m³ were sampled. This analytical strategy was applied to 10 indoor air samples collected in dwellings from the Valencian Region. Six pesticides, namely diphenylamine, pyrimethanil, bifenthrin, lambda-cyhalothrin, permethrin and cypermethrin were detected in indoor samples with concentrations ranging from 1.46 to 22.02 ng m^?3.     

A simple flow-injection chemiluminescence method for the determination of trace pentavalent vanadium in water samples

A simple method for rapid determination of trace pentavalent vanadium in natural water was presented by flow-injection chemiluminescence (CL). Through water injection, luminol and potassium permanganate were eluted from the anion exchange column to generate the CL, which was enhanced in the presence of V(V). Under the optimum conditions, the increased CL intensity was linear with V(V) concentration in the range from 0.1 to 100?ng?mL^?1. The limit of detection was 50?pg?mL^?1 (3σ) and the relative standard deviation (RSD) was 2.24% (n?=?5) for a 1.0?ng?mL^?1?V(V). At a flow rate of 2.0?mL?min^?1, one cycle of analysis could be performed in 0.5?min with a RSD of less than 3.0%. The proposed method was successfully applied to the determination of vanadium in natural water.     

Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source

The high‐sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NO_x^? (x = 2,3), O₃ and HNO₃ originating from plasma‐excited air were suggested to contribute to the formation of [TNT ? H]^? (m/z 226), [TNT ? NO]^? (m/z 197) and [TNT ? NO + HNO₃]^? (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd.     

Characterization of liquid chromatography-tandem mass spectrometry method for the determination of acrylamide in complex environmental samples

This work describes the characterization of a solid-phase extraction (SPE) and liquid-chromatography-tandem mass spectrometry-based method for the analysis of acrylamide (AA) in complex environmental waters. The method involved the SPE of AA using activated carbon, and the AA was detected with tandem mass spectrometry after separating on an ion exclusion high-performance liquid chromatography column. The method incorporated two labeled AA standards for quantification using isotope dilution and to assess absolute extraction recovery. The method was evaluated for inter- and intra-day precision and accuracy. The method was both accurate (i.e., <30 % error) and precise (i.e., <20 % relative standard deviation), with absolute extraction recoveries averaging 37 %. The mass spectrometry provided excellent sensitivity, with instrumental limits of detection and quantitation values of 23 and 75 pg, respectively. The method detection limit was determined to be 0.021 μg/L. The analysis of AA was successfully performed in real-world samples that contained total dissolved solids concentrations ranging from 23,600 to 297,000 mg/L and AA concentrations ranging from 0.082 to 1.0 μg/L.

Determination of Tranexamic Acid Using Ethyl Chloroformate as Derivatizing Reagent in Pharmaceutical Preparations and Blood by GC

Ethyl chloroformate was used as a derivatizing reagent to develop a simple and sensitive gas chromatographic procedure for the determination of tranexamic acid. Analysis was performed on an HP-5 column (30 m × 0.32 mm i.d.) coupled with mass spectrometric detection. Linear response was obtained from 60 to 500 pg with a limit of detection of 20 pg tranexamic acid injected onto the column. Aminocaproic acid was used as an internal standard. Tranexamic acid was determined in pharmaceutical preparations and blood samples after therapy with the drug. Appoximately 2.0 μg mL^?1 was found in blood samples. Relative standard deviation for analysis was within 0.1–0.4% (n = 3). Recovery of tranexamic acid added to deprotenized serum was 99.6% with an RSD of 1.2–1.6% (n = 3). Pharmaceutical additives and amino acids, if also present, did not affect the determination.     

Wide linear range nanomaterial/ionophore-based electrode used for determination of lead in environmental and biological samples with differential pulse voltammetry

A new chemically modified carbon paste electrode is fabricated to determine lead ion concentration in its trace level in aqueous media with differential pulse voltammetry (DPV). The best performance is obtained by the carbon paste electrode composition including 20% of dithiodibezoic acid (DDA), 80% of high purity graphite powder and 60?µL of colloidal gold nanoparticle (AuNP) solution. The proposed electrode has a wide linear calibration response from 1?×?10^?9 to 6?×?10^?5 M with a detection limit of 6.6?×?10^?10?M, at pH 3.5. Seven replicate determination of 5?×?10^?8?M of lead ion concentration gives a relative standard deviation of 3.33%. The modified sensor is applied to determine lead contents in some environmental and biological Samples with satisfactory results.     

Synthesis and characterization of an ion-imprinted polymer for selective solid phase extraction of thorium(IV)

A new surface ion-imprinted composite polymer containing 3-methyl-1-phenyl ?4-(cis-acylbutenoic acid)-2-pyrazolin-5-one as the functional reagent is presented that is capable of extracting and preconcentrating traces of Th(IV) ion prior to its photometric determination. Parameters affecting the recovery of Th(IV) such as acidity, shaking time, initial concentration of Th(IV), elution condition, sample flow rate, and influence of potentially interfering ions were investigated. The maximum uptake capacity of this material and that of the non-imprinted polymer at pH 4.5 are 56.8 and 26.3?mg?g^?1, respectively. Recovery exceeds 95% and is complete within 5?min. A Langmuir isotherm fits the experimental data. The relative selectivity factor for Th(IV)/U(VI), Th(IV)/La(III), and Th(IV)/Ce(III) are 50.8, 78.3, and 82.6, respectively. The relative standard deviation is <2.5%, the detection limit is 0.54???g?L^?1 (3??). The imprinted polymer was coupled to spectrophotometry to separate and determine trace levels of Th(IV) in a soil standard material with satisfactory results.

Poly(vinyl chloride) membrane electrode for the determination of verapamil

A verapamil-PVC membrane ion-selective electrode based on the verapamil-reineckate ion pair was prepared with dibutyl phthalate as a plasticizer. The electrode exhibited a linear response with a Nernstian slope (52.8 mV decade^?1 at 20° C) for verapamil concentrations of 10^?5?10^?2M over the pH range 3–7. The electrode also exhibited very good selectivity for verapamil with respect to various inorganic and organic cations. Gran II linear titration and potentiometric titration were used to determine verapamil in pure solution, with an average recovery of 99.3% and a relative standard deviation of 0.4%.     

Speciation analysis of orthophosphate and myo‐inositol hexakisphosphate in soil‐ and plant‐related samples by high‐performance ion chromatography combined with inductively coupled plasma mass spectrometry

A novel method based on high‐performance ion chromatography inductively coupled plasma mass spectrometry employing strong anion exchange chromatography with HNO₃ gradient elution for simultaneous analysis of orthophosphate and myo‐inositol hexakisphosphate (IP₆) in soil solution and plant extracts is presented. As inductively coupled plasma mass spectrometry analysis of phosphorus at m/z 31 is hampered by N‐based interferences, ³¹P was measured as ³¹P¹⁶O⁺ at m/z 47 employing dynamic reaction cell technique with O₂ as reaction gas. Orthophosphate and IP₆ were separated within a total chromatographic run‐time of 12 min revealing a limit of detection of 0.3 μmol/L. The coefficients of determination obtained in a working range of 1–100 and 1–30 μmol/L were 0.9991 for orthophosphate and 0.9968 for IP₆, respectively. The method was successfully applied to extracts from three different soils as well as root and shoot extracts of Brassica napus L. The precision of three independently prepared soil extracts was in the range of 4–10% relative standard deviation for PO₄^3? and 3–8% relative standard deviation for IP₆. Soil adsorption/desorption kinetics for IP₆/orthophosphate were performed for investigating the sorption behavior of the two P species in the experimental soils.     

Simultaneous quantification and qualification of synacthen in plasma

Tetracosactide (Synacthen), a synthetic analogue of adrenocorticotropic hormone (ACTH), can be used as a doping agent to increase the secretion of glucocorticoids by adrenal glands. The only published method for anti-doping control of this drug in plasma relies on purification by immunoaffinity chromatography and LC/MS/MS analysis. Its limit of detection is 300 pg/mL, which corresponds to the peak value observed 12 h after 1 mg Synacthen IM administration. We report here a more sensitive method based on preparation of plasma by cation exchange chromatography and solid-phase extraction and analysis by LC/MS/MS with positive-mode electrospray ionization using 7–38 ACTH as internal standard. Identification of Synacthen was performed using two product ions, m/z 671.5 and m/z 223.0, from the parent [M?+?5H]⁵⁺ ion, m/z 587.4. The recovery was estimated at 70%. A linear calibration curve was obtained from 25 to 600 pg/mL (R ²?>?0.99). The lower limit of detection was 8 pg/mL (S/N?>?3). The lower limit of quantification was 15 pg/mL (S/N?>?10; CV%?相似文献   

杭州市冬季大气气溶胶PM2.5中二恶英和多氯联苯的污染特征

2014年1月在杭州市选择5个点位采集大气颗粒物PM_2.5样品,采用同位素稀释高分辨气相色谱/高分辨质谱测定PM_2.5中的二恶英（PCDD/Fs）和多氯联苯（PCBs）,对PM_2.5的污染状况以及PM_2.5中PCDD/Fs和PCBs的污染水平及分布特征进行了研究。PM_2.5的质量浓度范围为85~168 μg/m³,PM_2.5污染较重,但与2004年同期相比明显降低。PM_2.5中PCDD/Fs的毒性当量（TEQ）为0.277~0.488 pg I-TEQ/m³,明显高于2004年同期采集样品。颗粒物中PCDD/Fs以八氯代二苯并-对-二恶英（OCDD）为主,毒性当量主要贡献者为2,3,4,7,8-五氯代二苯并呋喃（2,3,4,7,8-PeCDF）。PM_2.5中PCBs的质量浓度范围为2.9~8.1 pg/m³,二恶英类多氯联苯（DL-PCBs）的毒性当量范围为2.6~6.1 fg WHO-TEQ/m³,污染较低。PCBs在颗粒物中分布以PCB-28为主,但对毒性当量贡献最大的为PCB-126。PCDD/Fs和PCBs的气-固分配特征表现为PCDD/Fs主要分布于颗粒物中,而PCBs主要分布于气相中。     

Hydrophilic interaction chromatography with Fourier transform mass spectrometry of monosaccharide anhydrides

A fast, selective, and sensitive method for the determination of three monosaccharide anhydrides (galactosan, mannosan, levoglucosan), based on hydrophilic interaction chromatography and Fourier transform mass spectrometry, was successfully developed. The simple experimental stationary phase and mass spectrometry performance screening allowed the selection of the best available chromatographic and mass spectrometry conditions. Thus, the chromatographic separation was performed on a highly selective stationary phase containing a zwitterionic phosphorylcholine group and the monosaccharide anhydrides were detected as [M+HCOO]^? adduct in the negative mode. The method showed accuracy in the range of 84–111 and 89–102% with interbatch precision expressed as relative standard deviations of 5.6–15.4 and 5.0–9.0% for the aerosol extract and snow samples, respectively. The limit of quantification in absolute values ranged from 10 to 30 pg, the limit of quantification, expressed as concentration, ranged was 0.3–0.9 ng/m³ for aerosol and 10–20 ng/mL for snow samples. The method was successfully applied for the determination of monosaccharide anhydrides in aerosol and snow samples.     

Anodic stripping voltammetric determination of silver ion at a carbon paste electrode modified with carbon nanotubes

A carbon paste electrode (CPE) was modified with multi-wall carbon nanotubes and successfully applied to the determination of silver ion by differential pulse anodic stripping voltammetry. Compared to a conventional CPE, a remarkably improved peak current response and sensitivity is observed. The analytical procedure consisted of an open circuit accumulation step for 2?min in ?0.4?V, this followed by an anodic potential scan between +0.2 and?+?0.6?V to obtain the voltammetric peak. The oxidation peak current is proportional to the concentration of silver ion in the range from 1.0?×?10^?8 to 1.0?×?10^?5?mol?L^?1, with a detection limit of 1.8?×?10^?9?mol?L^?1 after an accumulation time of 120?s. The relative standard deviation for 7 successive determinations of Ag(I) at 0.1???M concentration is 1.99%. The procedure was validated by determining Ag(I) in natural waters.

Elemental Analysis of Phytotherapeutic Products by Inductively Coupled Plasma–Tandem Mass Spectrometry

A procedure for the determination of As, Cd, Cr, Ni, Pb, and V in phytotherapy medicines by inductively coupled plasma–tandem mass spectrometry is reported. The use of tandem mass spectrometry with oxygen into an octopole reaction system at various gas flow rates and the combination of on-mass and mass-shift modes was evaluated. Cadmium, Cr, Ni, and Pb were determined as free atomic ions while As and V were determined as the oxides AsO⁺ and VO⁺ in the same run. Samples were prepared by microwave-assisted digestion with dilute nitric acid and hydrogen peroxide. Two plant-certified reference materials (apple leaves and tomato leaves) were used to check the accuracy. For tandem mass spectrometry with 0.5?mL min^?1 O₂, recoveries in the 85–113% were typically obtained and no statistical differences were observed at the 95% confidence level (t-test) in comparison with the certified values. Using these conditions, the limits of detection for the method were 0.01, 0.0002, 0.008, 0.008, 0.003, and 0.002?µg g^?1 for As, Cd, Cr, Ni, Pb, and V, respectively. The procedure was used for the analysis of four phytotherapic drugs and the determined concentrations were up to 0.168?µg g^?1 As, 0.03?µg g^?1 Cd, 0.82?µg g^?1 Cr, 1.18?µg g^?1 Ni, 0.52?µg g^?1 Pb, and 2.4?µg g^?1 V with average precision values of 8% as the relative standard deviation. The found concentrations were compared with limits proposed in official guidelines and, in most cases, the values were below the maximum limits allowed.