Determination of traces of sodium alkylbenzenesulphonate by high-performance liquid chromatography. Application to water

Summary For the trace determination of sodium alkylbenzenesulphonate (ABS) by HPLC the following conditions were employed: Shimadzu ZORBAX SIL Column (5 m, 4.6 mm i.d. x 150 mm) as stationary phase, 0.2% ammoniaethanol (v/v) as mobile phase, UV detector at 225 nm, injection volume 12 l. The chromatograms of ABS were simple and sharp (detection limit of ABS 0.02 g in 12 l of ethanol). The calibration curves of ABS were linear in a concentration range of 0.03 0.3 g in 12 l of ethanol. In the case of linear sodium dodecylbenzenesulphonate positive errors of 1 4% were caused by non-ionic surfactants or laurylsulphate (6 times excess), 10 50% positive errors were caused by 2 6 times excess of household detergents.Standard water samples containing ABS were treated with a weak base anion-exchange resin, the adsorbed ABS were eluted, and then determined either by HPLC or by the methylene blue spectrophotometric method. Recoveries of ABS in water were about 92 107% by HPLC.

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Bestimmung von Spuren Natriumalkylbenzolsulfonat mit Hilfe der HPLC. Anwendung auf Wasser

Zusammenfassung Für die Spurenbestimmung von Natriumalkylbenzolsulfonat (ABS) durch HPLC werden die folgenden Bedingungen empfohlen:Shimadzu ZORBAX SIL (5 m, 4,6 mm x 150 mm) als stationäre Phase, 0,2% Ammoniak/Ethanol als mobile Phase, UV-Detektor bei 225 nm, Injektionsvolumen 12 l. Die erhaltenen Chromatogramme sind einfach und scharf (Nachweisgrenze 0,02 g in 12 ml Ethanol). Die Eichkurven sind im Konzentrationsbereich von 0,03–0,3 g in 12 l Ethanol linear. Im Falle des linearen Natriumdodecylbenzolsulfonats werden bei Anwesenheit von nicht-ionischen oberflächenaktiven Substanzen oder von Laurylsulfat in 6fachem Überschuß positiver Fehler von 1–4% erhalten; bei 2–6fachem Überschuß von Haushaltswaschmitteln ergeben sich positive Fehler von 10–50%.Standard-Wasserproben werden zunächst einer Behandlung mit einem Anionenaustauscher unterzogen, die adsorbierten ABS eluiert und durch HPLC oder nach der Methylenblaumethode analysiert. Wiederfindungsraten liegen bei 92–107%.

     

Determination of tetraethyllead and tetramethyllead using high performance liquid chromatography and electrochemical detection

Summary A new method for the separation of tetramethyllead (TML) and tetraethyllead (TEL) was developed using high-performance liquid chromatography. The electrochemical detection was examined with different electrodes. Amperometric and pulse-amperometric techniques were investigated and the optimal working potential for each electrode was determined. Linearity for the glassy carbon electrode was observed between 350 ng and 30 g; the detection limit is 310 ng (TML) resp. 340 ng (TEL). In case of the mercury gold electrode the linearity range was 300 g–3 g and the detection limit 1.5 m (TML) resp. 1.7 g (TEL).     

Synthesis,characterization and crystal structures of heterometallic trinuclear carbonyl sulfido clusters (η5-Cp)MoFeCo- (CO)8(μ3-S) and [(η5-Cp)Mo]2Fe(CO)7(μ3-S)

HFe2Co(CO)9(3-S) reacts with (5-Cp)Mo(CO)3Cl in refluxing THF to give heterometallic trinuclear clusters (5-Cp)MoFeCo(CO)8(3-S) and [(5-Cp)Mo]2Fe(CO)7-(3-S), which have been characterized by elemental analyses, i.r., 1H- and 13C-n.m.r. and X-ray crystal structure determination. An electrophilic addition–elimination sequence is proposed for their formation.     

Fällungsanalyse im Mikrogrammbereich: Eine neue Methode

Zusammenfassung Eine neue Methode zur Durchführung gravimetrischer Bestimmungen im Mikrogrammbereich wurde beschrieben; diese beruht im wesentlichen darauf, daß der Niederschlag nicht mehr zusammen mit dem Filter, sondern nach Überführen mit einem geeigneten Lösungsmittel in einem separaten Wägegefäß gewogen wird.Die dazu nötigen Geräte und deren Herstellung wurden beschrieben. Nach dieser Methode wurden folgende Bestimmungen mit zufriedenstellender Richtigkeit durchgeführt: 2,5–25g Al, 5–50g Cu und 5–50g Zn mit Oxin, 2,5–25g Fe(III) und 2,5–25g Ti(IV) mit N-Benzoyl-phenylhydroxylamin, 5–50g Ni und 5–50g Cu mit Salicylaldoxim, 2,5–50g Co(II) und 2,5–50g Fe(III) mit -Nitroso--naphthol sowie 5–50g Chlorid als Silberchlorid.

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Precipitation analysis in the microgram-scale: A new method

Summary A new method for gravimetric determinations in the microgram-scale is described. This method is based on the fact that the precipitate is not weighed together with the filter but is transferred to a separate weighingvessel using a suitable solvent. The necessary simple devices and their use are described. The following determinations were carried out with satisfying accuracy: 2,5–25g Al, 5–50g Cu and 5–50g Zn with Oxine, 2,5–25g Fe and 2,5–25g Ti withN-benzoylphenylhydroxylamine, 5–50g Ni and 5–50g Cu with salicylaldoxime, 2,52–50g Co and 2,5–50g Fe with -nitroso--naphthol and 5–50g chloride as silver chloride.

     

Extractive spectrophotometric determination of dioxouranium(VI) with the sodium salt of hexamethyleneiminecarbodithioate

The optimum conditions for the extractive spectrophotometric determination of dioxouranium(VI) with hexamethyleneiminecarbodithioate(HMICdt) have been established. Dioxouranium(VI) reacts with this ligand at pH 4.5 to form a yellowish-orange uncharged 12 metal-ligand complex which can be extracted by chloroform. The calibration graph was linear in the range of 1–20 g ml^–1 of dioxouranium(VI) at 335 nm. The molar absorptivity of the extracted species is 5.952×10³ l mol^–1 cm^–1 with Sandell's sensitivity of 0.04 g cm^–2. The average of 10 determinations of dioxouranium was 49.75 g for the samples containing 50 g of U(VI) and the variation from the mean at 95% confidence limit was 49.75±0.5955.     

Direction of the action of glycosidases fromLimnaea stagnalis on the carbohydrate groups of the (Fc)5 region of immunoglobulins M

The action of the combined glycosidases fromL. stagnalis on the carbohydrate groups of two monoclonal immunoglobins M (Waldenström's disease) — IgM_El (I) and IgM_Ser (II) — has been studied by the semiquantitative evaluation of densitograms of glycopeptides after their separation by disc electrophoresis in polyacrylamide gel. The accessibility of the oligosaccharide groups (OGs) to the action of the glycosidases according to the positions of the OGs in a particular domain of the (Fc)₅ region of a IgM decreases for (I) in the sequence C3 C4 > hinge, and for (II) in the sequence hinge > C4 > C3. The difference in the accessibilities of the OGs (I) and (II) is apparently explained by differences in the conformations of (I) and (II). A hypothesis has been put forward concerning the possibility of the partial degradation of (II) by the accompanying proteases.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 371–375, May–June, 1984.     

Zur Bestimmung N-substituierter Aniline mit Natriumchlorit

Zusammenfassung Es wird eine photometrische Bestimmungsmethode beschrieben für Anilin (40–720 g/ml), Monoäthylanilin (90–1650 g/ml) und Diäthylanilin (100–1600 g/ml) mit Natriumchlorit in äthanolisch-wäßrigen Lösungen, sowie für Diäthylanilin (85–1140 g/ml) und Dimethylanilin (30–330 g/ml) neben den primären und sekundären Aminen in essigsaurer Lösung mit demselben Reagens. Das Verfahren liefert gute Ergebnisse.

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Summary A photometric procedure is described for the determination of aniline (40–720 g/ml), monoethylaniline (90–1650 g/ml), and diethylaniline (100–1600 g/ml) with sodium chlorite in aqueous ethanolic solutions and of diethylaniline (85–1140 g/ml) and dimethylamline (30 to 330 g/ml) in presence of the primary and secondary amines in acetic acid solution using the same reagent. Good results have been obtained,

     

A toxic reagent-free method for normal-phase matrix solid-phase dispersion extraction and reversed-phase liquid chromatographic determination of aldrin,dieldrin, and DDTs in animal fats

A method for the determination of aldrin, dieldrin, DDT, DDE, and DDD contamination in animal fats (beef tallow, lard, and chicken fat) without using toxic reagents is developed, that uses high-performance liquid chromatography after the sample has been prepared by matrix solid-phase dispersion (MSPD) with acidic alumina oxide. A reversed-phase C₁-silica column with a mobile phase of 50% (v/v) ethanol solution (in water) and a photo-diode array detector were used for the determination. Average recoveries of the target compounds (0.2–5.0 g g^–1) ranged from 84–98%, with coefficients of variation of <5%. The limits of quantitation were 0.16 g g^–1 for AD, 0.10 g g^–1 for DD, 0.06 g g^–1 for DDT, 0.07 g g^–1 for DDE, and 0.05 g g^–1 for DDD. No toxic reagents were used at all.     

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.     

LC Method for the Determination of Multiple Components in a Compound Cold Formulation

An isocratic liquid chromatographic method for determination of acetaminophen (AMP), caffeine (CAF), chlorphenamine maleate (CPM) and guaiacol glyceryl ether (GGE) in a compound cold formulation is described. Separation and quantitation were achieved on a Diamonsil C18 column using a binary mixture of methanol and 1.5% aqueous acetic acid (55: 45, v/v, pH 3.6) as mobile phase delivered at 0.4 mL min^–1. Single wavelength detection was at 220 nm for all four drugs and the run time was < 10 min. The linearity, accuracy and precision of the method were found to be acceptable over the concentration ranges: 16.0–127.8 g mL^–1 for AMP, 6.0–48.2 g mL^–1 for CAF, 5.0–40.0 g mL^–1 for CPM and 10.1–80.6 g mL^–1 for GGE.     

Isocratic high-performance liquid chromatographic determination of plasma adenosine

Summary Due to manifold physiological and cardioprotective actions of adenosine, the demand for a simple but accurate method to determine its concentration in plasma is increasing. The aim of this study was firstly to develop a simple isocratic method instead of the gradient elution or peak-shifting techniques used earlier and secondly to check conflicting data on the composition of stop-solution, added to the sample in order to prevent changes in adenosine concentration. Isocratic elution improved signal to noise ratio and concentrations of 100 mol L^–1 dipyridamole and 2.5 mol L^–1 erythro-9(2-hydroxy-3-nonyl)adenine in the blood sample effectively prevented both adenosine formation and degradation, even without the use of a 5-ecto-nucleotidase inhibitor. Lowering the concentration of dipyridamole to 25 mol L^–1 caused more than a tenfold increase of adenosine concentration in two out of five cases and even 100 mol L^–1 dipyridamole alone is not sufficient to inhibit adenosine deaminase in blood samples.     

Flow injection analysis at μl/min flow rates

The characteristics of knitted open tube (KOT) figure eight reactors and coil reactors at l/min flow rates were compared using plate height (H) calculations and peak height measurements. Peak broadening independent of flow rate was seen for the figure eight KOT but not the coil at flow rates of 150–300 l/min. Below 150 /min, the plate height values of both reactors were inversely proportional to flow rate. It was concluded that a 0.5-m KOT figure eight reactor is the most effective way to introduce delay time for a 1 1 injection size and tubing of 0.3 mm I.D. Enhancement of peak height response was particularly pronounced at flow rates less than 100 l/min.     

Thiazane-2, 4-dithione and its 3-aryl derivatives

Reaction of 2-thiothiazane-4-one and its 3-aryl derivatives with phosphorus pentasulfide in toluene or dichloroethane gives thiazane-2, 4-dithione, or the corresponding 3-aryl derivatives. The compounds are characterized by absorption maxima (or bends) at three bands, 244–262, 315–321, and 339–350 m. The IR spectra exhibit bands at 14.93 (C-S-C), 6.64, and 6.84 (N-C-S), and 7.34, 8.43, 7.14 (CH₂).     

Spectrofluorimetric flow-injection determination of cerium in carbon and low alloy steels

Cerium can be determined spectrofluorimetrically (_em 350 nm, _ex 260 nm) based on the relatively intense native fluorescence of the cerium(III) aquo-ion. The main potential interference in the analysis of steel from iron(III), cerium(IV) and chromium(VI) are removed by use of a carrier solution containing 2.5% w/v hydroxylammonium chloride. The slight residual interference from iron(II) can be corrected by a matrix matching factor linearly related to the amount of iron present. The calibration graphs are linear over the range 0–7 g ml^–1 based on 250 l injection volumes. The sampling rate was 30 h^–1. The relative standard deviation was 2.0% (n=5) at 3 g ml^–1 cerium. The system has been applied to the determination of cerium in carbon or low alloy steels.     

The relative importance of temperature and isotope effects on the dipole oscillator strength distribution of H2

Summary The calculation of the effects of temperature and isotopic composition on the energy weighted moments of the dipole oscillator strength distribution of H₂ in the random phase approximation to the polarization propagator are reported. It is seen that the effect of isotopic composition is small, while that of temperature is of an order accessible to experiment. We find that all the mean excitation energiesI , for =–1, 0, 1, decrease with temperature as does the dipole oscillator strength momentS() for >0, while the opposite is true for <0. These effects are interpreted in terms of the bond length dependence of the excitation energies.     

Addition of HCl to a Cluster-Bound Vinylidene Ligand: Preparation and Structure of Ru5(μ3-SMe)(μ3-CMe)(μ-Cl)(μ-SMe)(μ-PPh2)2(CO)9·PhMe

Addition of aqueous HCl to Ru₅( ₃-C=CH₂)(-SMe)₂(-PPh₂)₂(CO)₁₀ afforded the structurally characterized carbyne complex Ru₅( ₃-SMe)( ₃-CMe)(-Cl)(-SMe)(-PPh₂)₂(CO)₉, formed by addition of H to the vinylidene ligand; a Cl atom bridges an Ru–Ru bond.     

Synthesis of 5-arylidene derivatives of thiazane-2, 4-dithione

Thiazane-2,4-diones and their 3-aryl derivatives readily condense with aromatic aldehydes to give 5-arylidene derivatives. The compounds obtained are characterized by absorption maxima in the 290–310 m band, as well as by ill-defined bands at 260–270 and 420–440 m. The IR spectrum of 5-benzylidenethiazane-2, 4-dithione has bands at 7.02 (N-C-S), 7.52 (CH₂), 14.62 and 15.01 (C-S-C).     

Nickel(II) xanthates with nitrogen heterocycles as bridging ligands

New homopolynuclear nickel(II) xanthate complexes with nitrogen donor heterocycles as bridging ligands have been prepared, namely [Ni(Rxa)2(-L)]n and [Ni2(Rxa)4(-L1)], where R=i-Pr,i-Am; xa=OCS2– L=1,2-bis(4- pyridyl)ethane (bpe), 4,4-dithiodipyridyl (dtp), 1,2-bis(4- pyridyl)ethylene (dpe), 4,4-trimethylene-dipyridine (tmd); L1=2,3-bis(2-pyridyl)pyrazine (bpp), 2,4-bis(5,6- diphenyl-1,2,4-triazine-3-yl)pyridine (bdt), or 2,4,6-tris(2- pyridyl)-1,3,5-triazine (tpt). The compounds have been characterized by elemental analyses, i.r. and electronic spectroscopies, magnetochemical and conductivity measurements. The results show that the [Ni(Rxa)2(-L)]n complexes are linear polymers in which the nitrogen heterocycles bridge between the nickel(II) ions, which are coordinated by four sulfur and two nitrogen atoms and have trans-octahedral geometry. The nearly constant values of the effective magnetic moment (3.36–3.34 eff/B) over the 77–295 K temperature range indicate that exchange interactions are lacking among the paramagnetic centres in the linear structure, [Ni(i-Amxa)2(dpe)]n. The variable- temperature magnetic susceptibilities of the [Ni2(i-Prxa)4(bpp)] (3.00–2.95eff/B per Ni atom), [Ni2(i-Prxa)4(bdt)] (2.72–2.63 eff/B per Ni atom), and [Ni2(i-Amxa)4(tpt)] (2.76–1.87 eff/B per Ni atom) were measured down to liquid nitrogen temperature. In the case of binuclear nickel(II) complexes with bdt or tpt, antiferromagnetic coupling between the nickel(II) ions was detected, giving the exchange integral J=–4.0cm–1 and –29.6cm–1, respectively.     

Production of certified reference material

Summary Carbon has been determined in 31 European reference steels in the range of 11–2561 g/g C, using an absolute calibration method.High-purity calcium carbonate was used as the calibration material and weighing was carried out by means of a balance with extremely small weighing error. Both synthetic calibration samples and test samples were processed alternatingly under identical conditions, and the analyses were completed in the shortest possible time.In 28 of the cases examined, results were lower than the certificate values, by an average of 27 g/g. The interval of uncertainty of the accuracy was 6 g/g (probability 99%).

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Herstellung zertifizierter ReferenzmaterialienGenaue Bestimmung von Kohlenstoff in Stählen im Bereich von 11–2561g/g

Zusammenfassung Die Kohlenstoffgehalte von 31 europäischen zertifizierten Referenzstählen im Arbeitsbereich von 11–2561 g/g Kohlenstoff wurden durch absolute Eichung überprüft.Die hinreichende Reinheit des Eichmittels Calciumcarbonat wurde sichergestellt und ein Wägesystem mit einem hinreichend kleinen Wägefehler benutzt.Das gleiche Verhalten von synthetischen Eichproben und Analysenproben im Analysenprozeß wurde hergestellt und beide Probearten wechselweise unter konstanten Systembedingungen innerhalb kürzester Zeitspanne untersucht. In 28 der untersuchten Fällen wurden im Mittel um 27 ppm tiefere Werte gefunden als in den Zertifikaten angegeben. Das Unsicherheitsintervall der Richtigkeit der gefundenen Werte lag mit einer Wahrscheinlichkeit von 99% im Mittel bei 6 g/g.

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Abbreviations CRM Certified reference material - ppm g/g The author thanks Mr. E. Weichert for his excellent direction of the practical work.