Erratum to: Simultaneous High-Performance Thin-Layer Chromatographic Determination of Indole Acetic Acid,Indole Butyric Acid,and Absisic Acid in in vitro Seedling of Watermelon Exposed to Heavy Metals

JPC – Journal of Planar Chromatography – Modern TLC - Simultaneous High-Performance Thin-Layer Chromatographic Determination of Indole Acetic Acid, Indole Butyric Acid, and Absisic Acid...     

Quantification of volatile sulfur compounds related to the corrosion of concrete sewers

Summary A gas-chromatographic procedure for the determination of volatile sulfur compounds related to the formation of the substrate for sulfuric acid producing thiobacilli is described. Volatile sulfur compounds from head-space samples of the sewer atmosphere are qualitatively and quantitatively determined with a sulfur-selective detector. The concentrations are correlated with the occurrence of concrete corrosion in sewage systems.

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Quantifizierung flüchtiger Schwefelverbindungen im Zusammenhang mit der Korrosion von Beton-Abwasserkanälen

Zusammenfassung Es wird ein gas-chromatographisches Verfahren zur Bestimmung flüchtiger Schwefelverbindungen beschrieben, die mittelbar an der Substratbildung für Schwefelsäure bildende Thiobazillen beteiligt sind. Flüchtige Schwefelverbindungen in Original-Luftproben aus Abwassersammlern werden mittels eines für Schwefel selektiven Detektors qualitativ und quantitativ bestimmt und mit dem Auftreten von Betonkorrosion in Abwasserkanälen korreliert.

     

The effect of orientation on the radiation induced degradation of polymers

A study has been made of the effect of orientation on the oxidative degradation of poly(vinylchloride) (PVC), low density polyethylene (LDPE) and high density polyethylene (HDPE) under the influence of γ- and u.v.-radiation. The effect of drawing in PVC is to increase the rate of oxidative degradation; in LDPE and HDPE, this rate decreases (especially for HDPE) both under u.v. and γ-radiation.     

Palladium-pincer complex catalyzed C-C coupling of allyl nitriles with tosyl imines via regioselective allylic C-H bond functionalization

A mechanistically new palladium-pincer complex catalyzed allylation of sulfonimines is presented. This reaction involves C-H bond functionalization of allyl nitriles under mild conditions. The reaction proceeds with a high regioselectivity, without allyl rearrangement of the product. Modeling studies indicate that the carbon-carbon bond formation process proceeds via (eta (1)-allyl)palladium pincer complex intermediates.     

Stereoselective Pincer-complex catalyzed C-H functionalization of benzyl nitriles under mild conditions. An efficient route to beta-aminonitriles

An efficient palladium pincer-complex catalyzed reaction has been developed for alpha-C-H bond functionalization of benzyl nitriles. The studied coupling reaction with sulfonylimines affords beta-aminonitriles with usually high levels of stereoselectivity. The stereoselectivity of the process is highly dependent on the electronic effects of the ortho substituents of the benzyl moiety. Promising levels of enantiomeric excess are obtained using chiral pincer complexes as catalysts.     

Time-resolved investigations of laser-induced plasmas generated by nanosecond bursts in the millijoule burst energy regime

Laser-induced plasmas are investigated during laser micro structuring of a C 75 steel alloy using laser bursts that consist of nanosecond laser pulses under atmospheric pressure. The influence of the laser burst mode — single and collinear double pulses — on plasma dynamics and ablation efficiency is investigated for burst energies in the millijoule regime. Electron density and excitation temperatures measured as a function of time. The results are compared with published data looking for changes of the plasma parameters scaling with the burst energy over two orders of magnitude. For collinear double pulses at burst energies of 1–2 mJ an increase of the ablation rate by a factor of three to four compared to single pulses was observed.     

Detection of microphase separation in poly(tert-butyl acrylate-b-methyl methacrylate) synthesized via atom transfer radical polymerization by inverse gas chromatography

A trace amount of solvents such as n-octane, n-nonane, n-decane, ethyl acetate, n-propyl acetate, isoamyl acetate, toluene, ethyl benzene, n-propyl benzene, isopropyl benzene and chloro benzene was passed through the column of a gas chromatograph of which the stationary phase is poly(tert-butyl acrylate-b-methyl methacrylate), poly(tBA-b-MMA), block copolymer with low polydispersity, prepared via ATRP of tBA and MMA, respectively. The retention diagrams to determine the thermal transition of the polymer were obtained by plotting the logarithm of the specific retention volumes of isoamyl acetate and toluene against reciprocal values of absolute column temperatures between 40 and 170 °C by inverse gas chromatography (IGC) technique. Three glass transition temperatures, T_gs of poly(tBA-b-MMA) were determined at 50, 70 and 105 °C by IGC indicating the phase separation of the polymeric blocks in the copolymer. The thermodynamical interaction parameters such as weight fraction activity coefficient of solvent at infinite dilution, , Flory-Huggins polymer-solvent interaction parameter, , equation-of-state polymer solvent interaction parameter, , effective exchange energy parameter, X_eff, and solubility parameter of the copolymer, δ₂ were calculated at studied temperatures. The closeness of parameters of the poly(tBA-b-MMA) to those of the PMMA indicated that the continuous phase is MMA block in the microphase separated block copolymer. It seems that IGC is a reliable technique to study a phase separated block copolymer which contains nanosized domains.