Characterization of airborne particulates by laser microprobe mass analysis

Summary Laser microprobe mass analysis (LAMMA) was applied to characterize aerosol particles collected and separated from 16m to 0.06m by a low pressure cascade impactor. Positive ion LAMMA spectra showed characteristic molecular peaks such as PbCl⁺, a series of Si₂O⁺–Si₂O₄ ⁺ and NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, and TiO⁺ in 0.06–0.12m, 0.5–1m and 4–8m fraction, respectively. In the negative ion LAMMA spectra, it was observed that the fragment peaks of sulfate ions were deficient above 2m and those of nitrate ions were deficient under 2m. LAMMA allows remarkable insights into the chemical nature of aerosol particles.

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Charakterisierung luftgetragener Teilchen durch Laser-Microprobe-Massenspektrometrie

Zusammenfassung Laser-Microprobe-Spektrometrie (LAMMS) wurde zur Analyse atmosphärischen Aerosols herangezogen, welches im Korngrößenbereich zwischen 16m und 0.06m mit einem Niederdruckkaskadenimpaktor fraktioniert gesammelt wurde. Positive LAMMS-Spektren zeigten charakteristische molekulare Peaks, wie etwa PbCl⁺, eine Serie von Si₂O⁺–Si₂O₄ ⁺ und NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, sowie TiO⁺ in der 0,06–0,12-m,- 0,5–1–m- bzw. 4–8-m-Fraktion. In den negativen LAMMS-Spektren konnten über 2m keine Fragmentpeaks für Sulfationen, unter 2m. keine für Nitrationen beobachtet werden. LAMMS ermöglicht eine bemerkenswerte Einsicht in die chemische Natur von Aerosolteilchen.

     

Platinum concentration in silicone breast implant material and capsular tissue by ICP-MS

Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the concentration of platinum (Pt) in silicone breast implant gel (range, 0.26–48.90 g g^–1 Pt; n=15), elastomer (range, 3.05–28.78 g g^–1 Pt; n=7), double lumen (range, 5.79–125.27 g g^–1 Pt; n=7), foam (range, 5.79–8.36 g g^–1 Pt; n=2), and capsular tissue (range, 0.003–0.272 g g^–1 Pt; n=15). The results show that very high levels of Pt are present in the encasing elastomer, double lumen, and foam envelope materials. Silicone breast implants can be a source of significant Pt exposure for individuals with these implants.     

Photometric determination of molybdenum in iron and steels using tin(II) chloride in nonaqueous solvent

Summary A new procedure is proposed for the photometric determination of molybdenum in iron and steels using thiocyanate and tin(II) chloride solution [in glycerol-ethannol (31) or in diethylenglycol] as a reducer and extraction with n-butyl acetate. Beer's law is obeyed between 0.2 and 80 g Mo/ml. The minimum photometric error is 3.2%, the molar absorptivity is 15640 at 470 nm and the best concentration range for determination is between 0.6 and 6 g Mo/ml.

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Photometrische Bestimmung von Molybdän in Eisen und Stahl mit Hilfe von Zinn(II)-chlorid in nichtwärigem Medium

Zusammenfassung Das vorgeschlagene Verfahren beruht auf Bildung des Thiocyanatkomplexes unter Verwendung von Zinn(II)-chlorid als Reduktionsmittel [in Glycerin/Äthanol (31) oder Diäthylenglykol]. Als Extraktionsmittel dient n-Butylacetat. Das Beersche Gesetz wird im Bereich 0,2–80 g Mo/l befolgt. Der kleinste photometrische Fehler beträgt 3,2%, die molare Extinktion 15640 bei 470 nm und der optimale Konzentrationsbereich 0,6–6 gMo/l.

Lecture presented at Euroanalysis I Conference, 28. 8. –1. 9. 1972 in Heidelberg, Germany.     

Thallium determination in reference materials by Isotope Dilution Mass Spectrometry (IDMS) using thermal ionization

Summary Using Isotope Dilution Mass Spectrometry (IDMS) with thermal ionization, thallium concentrations were determined in reference materials from NIST and BCR, from other sources, and reference materials from the German Environmental Specimen Bank. ²⁰³Tl spike solution is applied for the isotope dilution technique. Thallium concentrations in the investigated materials range from 2.67 g Tl·kg^–1 to 963 g Tl·kg^–1 with a relative standard deviation from 0.14 to 10%. The detection limit was 0.1 ng thallium for this work.     

The composition of volatile and particulate hydrocarbons in urban air

Summary The hydrocarbon composition of the particle and gas phases in the urban atmosphere has been studied by filtration and parallel adsorption on active charcoal and polyurethane foam (PUF). Gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS) have been used for the analysis of the organic matter extracts obtained with each system. In the case of the particle and PUF samples these extracts were fractionated into aliphatic and aromatic compounds. This approach has allowed to identify up to 247 hydrocarbon molecules showing that C0–C5 alkylbenzenes are the major compounds in the charcoal extracts whereas C14–C23 n-alkanes, C0–C4 alkylnaphthalenes, C0–C4 alkylbiphenyls and C3–C5 alkylbenzenes are those predominantly found in the PUF materials. The particles essentially contain C17–C38 n-alkanes and parent polycyclic aromatic hydrocarbons (PAH). These qualitative differences are paralleled by a progressive concentration decrease from the more to the less volatile hydrocarbons. Thus, the total charcoal extracts average 80 g/m³, the PUF compounds represent 4 /m³ and the particle hydrocarbons 0.7 g/m³. These latter airborne materials are essentially composed of petrogenic residues 0.6 g/m³ (aliphatic fraction) whereas the pyrolytic PAH only involve 0.08 g/m³.     

Selective determination of neodymium and erbium in mixtures with other lanthanides by second-derivative spectrophotometry of complexes with benzoyl-indan-1,3-dione and cetylpyridinium chloride

The absorption spectra of 4f electron transitions of the neodymium and erbium complexes with benzoyl-indan-1,3-dione and cetylpyridinium chloride have been studied by conventional and derivative spectrophotometry. The second-derivative spectrum has been used to eliminate the interference of the other lanthanides, and to increase the sensitivity by a further factor of 4–6. Beer's Law is obeyed for 6–29 g/ml Nd and 7–33 g/ml Er. The relative standard deviations evaluated from 10 independent determinations of 5.0 g/ml Nd and Er were 1.1% (Nd) and 1.6% (Er). The detection limits obtained from the sensitivity of the calibration graphs and 3s _b, (standard deviation of the blank,n = 11) were 0.63 g/ml Nd and 0.61 g/ml Er. The quantification limits (10s _b) were 2.1 g/ml Nd and 2.0 g/ml Er. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.     

Titrimetric determination of thiourea and silver with a picrate ion selective electrode

Summary A method has been developed for the semiautomatic potentiometric titration of thiourea with silver nitrate and of silver with thiourea, in the presence of picrate ions, using a picrate ion selective electrode. Thiourea in the range 15–1500g and silver in the range 200–1800g were determined with relative errors and relative standard deviation of about 1%.

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Zusammenfassung Eine halbautomatische potentiometrische Titrationsmethode für Thioharnstoff mit Silbernitrat bzw. umgekehrt in Gegenwart von Pikrationen mit Hilfe einer selektiven Pikratelektrode wurde entwickelt. 15–1500g Thioharnstoff bzw. 200–1800g Silber wurden mit einem relativen Fehler und einer relativen Standardabweichung von etwa ±1% bestimmt.

     

Simultaneous Determination of Four Active Components in a Compound Formulation by Liquid Chromatography

Summary A rapid and accurate LC method is described for simultaneous determination of pseudoephedrine hydrochloride (PSE), acetaminophen (AMP), dextromethorphen hydrobromide (DEX), and diphenhydramine hydrochloride (DPH) in a compound formulation. Chromatographic separation of the four drugs was achieved on a Hypersil CN column (150 mm × 4.6 mm, 5 m particle) by use of a mobile phase comprising a mixture of 3 mM ion-pairing solution, 2% aqueous triethylamine solution, and 2 M phosphoric acid, 68:48:88 (v/v), pH 3.0, delivered at 1.0 mL min^–1. Compounds were detected at 215 nm and the run time was less than 10 min. The linearity, accuracy, and precision of the method were found to be acceptable over the concentration ranges 6.1–36.4 g mL^–1 for PSE, 65.0–390.0 g mL^–1 for AMP, 3.1–18.6 g mL^–1 for DEX, and 5.0–30.0 g mL^–1 for DPH.     

Effect of Surfactants on the Immobilization of 4-(2-Pyridylazo)resorcinol on Silochroms

The effect of cationic surfactants (cetyltrimethylammonium bromide, cetylpyridinium bromide, and tetrabutylammonium perchlorate) and a nonionic surfactant (OP-7) on the conditions of the immobilization of 4-(2-pyridylazo)resorcinol (PAR) on three types of silica gel (Silochrom S-120 (200–350 m), Silochrom S-120 (315–500 m), and Silochrom S-80 (200–350 m)) was studied. It was found that OP-7 does not affect the adsorption of surfactants. The effect of cationic surfactants increases in the order tetrabutylammonium perchlorate < cetyltrimethylammonium bromide < cetylpyridinium bromide. The adsorption activity of silica gels increases in the order Silochrom S-120 (315–500 m) < Silochrom S-80 (200–350 m) < Silochrom S-120 (200–350 m). Cetylpyridinium bromide provides full immobilization of PAR on silica gel Silochrom S-120 (200–350 m) in the pH range 2–9.     

Fluoridbestimrnung in Wasser und Luft mit ionenselektiven Elektroden

Zusammenfassung Systematische Bestimmungen des Fluoridgehaltes in verschiedenen Wasserproben aus Serbien und in Luftproben aus einigen In-dustriegebieten und aus der Stadt Belgrad wurden durchgeführt. Außerdem wurde der Fluoridgehalt in einigen meistkonsumierten Mineralwässern aus alien Territorien Jugoslawiens geprüft. Etwa 600 Proben wurden analysiert. Die Ergebnisse sollen für die kartographische Erfassung der Verteilung von Fluor im Trinkwasser dienen.

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Determination of fluoride in Yugoslavian air and water with an ion-sensitive electrode

Summary Fluoride has been measured in over 600 samples of air and water with an ion-sensitive electrode. The concentrations found in the air samples were 1.6–l08g/m³ for industrial areas, 1.9–25.6g/m³ for urban areas and 1.1–18.4g/m³ for rural areas. Most of the samples had fluoride levels below 20g/m³3. The concentrations found in water samples were 0.12–0.34g/litre for drinking water and 0.27–5.6g/litre, for mineral waters.

     

Spectrophotometric determination of mercury with 5,10,15,20-tetrakis(3-chloro-4-sulfophenyl)porphine by flow injection analysis

5,10,15,20-tetrakis(3-chloro-4-sulfophenyl)porphine (m-Cl-TPPS₄) was synthesized and used for the Spectrophotometric determination of mercury by flow injection analysis. A pseudo-first-order reaction kinetic mechanism was proposed with a rate constant of 0.8 min^–1 for Hg(II) withm-Cl-TPPS₄ in the presence of 8-hydroxyquinoline in a medium of 1.0M acetic acid and sodium acetate buffer solution (pH 6.22). In the optimum conditions of reaction temperature (85 ° C), stopped-flow time (60 s) and sampling volume (100 l), the method's relative standard deviation was 0.82% (n = 12) at 5.0 g ml^–1 mercury, with a linear range of 0–12.0 g ml^–1 and an analytical frequency of 60h^–1. The detection limit (3) was 0.025 g ml^–1. Interference studies showed that most metal ions co-existing with Hg²⁺ could be tolerated at 100-fold excess levels, but Zn²⁺, Cu²⁺ and Mn²⁺ needed to be masked. The method has been applied to the analysis of water samples with satisfactory results.     

Using enzymes isolated from diverse sources to determine metal ion cofactors

Oxidoreductases and hydrolases isolated from different sources (horseradish and peanut peroxidases, alcohol dehydrogenases from bakers yeast and horse liver, and alkaline phosphatases from Escherichia coli, chicken and seal intestine) were used to determine their metal ion cofactors: Fe(III), Zn(II) and Mg(II), respectively. Studying the effects of the metal ion cofactors on the catalytic activity of the enzymes of different origin showed that the extent of their inhibition, activation, or reactivation of their apoenzymes depended on the structure and accessibility of the enzyme active site, which varies among the biocatalysts isolated from different sources. The developed procedures are based on the inhibiting (Zn(II)) or activating (Mg(II)) effects of the metal ions on the catalytic activity of the enzymes, or on reactivating effects (Fe(III) and Zn(II)) on the apoenzymes. The procedures are characterized by high sensitivity and selectivity; the detection limits of Fe(III) using horseradish peroxidase, Zn(II) using alcohol dehydrogenase from bakers yeast, alkaline phosphatase from seal intestine and its apoenzyme, and Mg(II) using alkaline phosphatase from chicken intestine equal 10 ng L^–1, 20 ng L^–1, 3 g L^–1, 8 g L^–1 and 0.2 g L^–1, respectively.Presented at the 8th Symposium Kinetics in Analytical Chemistry, Rome, Italy, 5–8 July 2004.     

Path of “dry” electrons before localization in liquid hydrocarbons

Conclusions On the basis of measurements of values of in liquid hydrocarbons, it has been shown that the path length before localization of a photoliberated electron increases with increasing mobility of the excess electron, from approximately 40 Å (methylcyclohexane) to 200 Å (isooctane). In a liquid with10^–2 cm²/V·sec (methylcyclohexane, hexane), the localization takes place before or immediately after thermalization of the electron. In a liquid with>10^–1 cm²/V·sec, the electron passes through the main part of its path before localization, being in thermal equilibrium with the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2198–2203, October, 1985.     

Determination of pentachlorophenol residues in wine and corks by solvent extraction methodology and specific gas chromatography detection

Summary A gas chromatographic methodology with selective detection is presented for the analysis in wines and corks of pentachlorophenol residues, which are suspected to be the most likely precursors of some off-flavours described in several wine samples. After derivatisation, pentachlorophenol acetate residues were monitored by electrolytic conductivity detection and/or mass spectrometric detection in the selective ion mode at m/z 264 and 266. Recoveries varied from 80 to 96% for wine samples fortified with 5 to 100 g l^–1 and from 83 to 91% for corks (fortified at 25 to 100 g kg^–1). The proposed methodology allowed for a determination limit of g l^–1 for wine and 10 g kg^–1 for corks.     

Development and application of a simple routine method for the determination of selenium in serum by octopole reaction system ICPMS

The aim of the study was to develop an inductively coupled plasma mass spectrometry (ICPMS) method for robust and simple routine determination of selenium in serum. Polyatomic interferences on ⁷⁶Se, ⁷⁷Se, and ⁷⁸Se were removed by applying an octopole reaction system ICPMS with the reaction cell pressurized with H₂ gas. We developed a novel simple optimization routine for the H₂ gas flow based on a signal-to-noise ratio (SNR) calculation of the selenium signal measured in a single selenium standard. The optimum H₂ flow was 2.9 mL min^–1. The selenium content in serum was determined after a 50-fold dilution with 0.16 M HNO₃ and quantified by using addition calibration and gallium as an internal standard. The method detection limit was 0.10 g L^–1 for ⁷⁶Se and ⁷⁸Se and 0.13 g L^–1 for ⁷⁷Se. Human serum samples from a case-control study investigating if selenium was associated with risk of colorectal adenoma were analyzed. The average selenium concentration for the control group (n=768) was 137.1 g L^–1 and the range was 73.4–305.5 g L^–1. The within-batch repeatability (a batch is ten samples) estimated from 182 replicate analyses was 6.3% coefficient of variation (CV), whereas the between-batch repeatability was 7.4% CV estimated from 361 replicates between batches. The method accuracy was evaluated by analysis of a human serum certified reference material (Seronorm Serum level II, Sero A/S, Norway). There was a fairly good agreement between the measured average of 145±3 g L^–1 (n=36) and the certified value of 136±9 g L^–1. In addition the method was successfully applied for analysis of zinc serum concentrations without further optimization. For the Seronorm certified reference material a value of 911±75 g L^–1 (n=31) for zinc was obtained, which corresponds well to the certified zinc value of 920±60 g L^–1.     

Determination of pyrimethanil and kresoxim-methyl in soils by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) then gas chromatography–mass spectrometry with selected ion monitoring (GC–MS, SIM) has been developed for determination of trace amounts of the fungicides pyrimethanil and kresoxim-methyl in soil and humic materials. Both fungicides were extracted on to a fused-silica fibre coated with 85 m polyacrylate (PA). Response-surface methodology was used to optimise the experimental conditions. For soil samples the linear dynamic range of application was 0.004–1.000 g g^–1 for pyrimethanil and 0.013–1.000 g g^–1 for kresoxim-methyl. The detection limits were 0.001 g g^–1 and 0.004 g g^–1 for pyrimethanil and kresoxim-methyl, respectively. HP-SPME–GC–MS analysis was highly reproducible—relative standard deviations (RSD) were between 6.7 and 12.2%. The method was validated by analysis of spiked matrix samples and used to investigate the presence of pyrimethanil and kresoxim-methyl above the detection limits in soil and humic materials.     

Application of l-cysteine-capped nano-ZnS as a fluorescence probe for the determination of proteins

Nanometer-sized l-cysteine-capped ZnS particles have been synthesized and used as a fluorescence probe to investigate the effect of proteins on fluorescent intensity. With =190 nm, maximum and constant synchronous fluorescence enhancement was produced at 267 nm and pH 5.12 in the presence of proteins. A highly sensitive synchronous fluorescence method for the rapid determination of proteins has been developed. Under optimum conditions, calibration graphs are linear over the range 0.03–8.0 g mL^–1 for bovine serum albumin (BSA), 0.01–6.0 g mL^–1 for human serum albumin (HSA), 0.05–8.0 g mL^–1 for -globulin (-G), and 0.04–4.0 g mL^–1 for ovalbumin, respectively. The relative standard deviations of seven replicate measurements were 1.75% for 1.0 g mL^–1 BSA, 1.90% for 1.0 g mL^–1 HSA, 1.65% for 1.0 g mL^–1 -G, and 2.32% for 1.0 g mL^–1 ovalbumin.     

Bestimmung flüchtiger organischer Verbindungen in atmosphärischen Aerosolproben durch thermische Desorption und FID-Detektion

Zusammenfassung Staub- und Aerosolproben werden im Stickstoffstrom im Temperaturbereich 25–420° C einer temperaturprogrammierten thermischen Desorption unterworfen. Die flüchtigen organischen Komponenten werden mittels FID summarisch als volatile organic carbon (VOC) bestimmt. Die Eichung des Analysators erfolgt durch ein Aliphaten-Standardgemisch. Bei Probemengen von 50–100g Aerosol ist eine Bestimmung des VOC-Gehaltes mit einer Reproduzierbarkeit vons=3,5–7 rel.% möglich. Die Nachweisgrenze der Methode liegt für Aerosolproben bei 0,3g VOC.

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Determination of volatile organic components in atmospheric aerosol samples by thermal desorption and FID-detection

Summary Atmospheric dust and aerosol samples are treated in a nitrogen carrier gas stream at the temperature range 25–420° C by temperature programmed desorption. The volatile organic components are detected by FID. Calibration of the analyzer is carried out with a standard mixture of aliphatic hydrocarbons. The result is expressed as volatile organic carbon (VOC). The reproducibility of the method for aerosol samples (sample weight 50–100g) is in the range of 3,5–7% r. s. d. The detection limit of the method is 0,3g VOC.

     

GC/MSD detection of the metabolic residues of metolachlor in tomato fruit

Summary A gas chromatograph/mass selective detector method is presented for the analysis of the major metabolic residues of metolachlor by acid hydrolysis of tomato fruit. The two major hydrolysis products, CGA-37913 (2-[2-ethyl-6-methylphenyl]amino-1-propanol) and derivatised CGA-49751 (4-[2-ethyl-6-methylphenyl]-2-hydroxy-5-methyl-3-morpholinone) were monitored in the selective ion mode atm/z 162 andm/z 160, respectively. Recoveries from 87 to 96% were obtained for tomato fortified at 50 to 200g kg^–1. The proposed method of analysis will allow for a detection limit of 11 g kg^–1 for CGA-37913 and 12 g kg^–1 for the derivatised CGA-49751.