Automation of Potentiometric Measurements: Determination of Water-Extractable Sodium in Bread Using a Sodium Ion Selective Electrode with Minimum Sample Preparation

Different automated potentiometric procedures for the determination of NaCI in bread have been investigated and evaluated. The results are compared with data from atomic absorption spectrophotometry (AAS). A continuous potentiometric Na+ determination using a sodium ion selective electrode (ISE) is superior to all other methods. The sodium content can be measured by a reliable, rapid, and inexpensive potentiometric measurement of a finely ground and dried bread sample, extracted in the measurement beaker, as an alternative to the conventional and time-consuming AAS procedure.

Description of the nanostructured morphology of [6,6]-phenyl-C61 -butyric acid methyl ester (PCBM) by XRD, DSC and solid-state NMR

PCBM or [6,6]-phenyl-C(61)-butyric acid methyl ester is nowadays still one of the most successful electron acceptors for plastic bulk heterojunction (BHJ) photovoltaic devices. In this study, a set of complementary techniques, i.e. solid-state NMR, XRD and DSC, is proposed as a fast and sensitive tool to screen the morphology of PCBM specimens with different preparation histories. Based on proton NMR relaxation decay time values, an interval can be derived that situates the average crystal dimensions and which can further be refined on the basis of XRD patterns and DSC thermograms.

Thermogravimetric desorption and de novo tests I: method development and validation

Thermogravimetric analysis (TGA) has been combined with evolved gas analysis (EGA) with the purpose of simulating the thermal behaviour of filter dust samples under inert (desorption) and de novo test oxidising conditions. Emphasis is on studying de novo formation of dioxins, surrogates and precursors arising from filter dust derived from thermal processes, such as municipal solid waste incineration and metallurgy. A new method is tested for sampling and analysing dioxin surrogates and precursors in the TGA effluent, which are collected on sampling tubes; the adsorbed compounds are eventually desorbed and quantified by TD-GC-MS. The major sources of error and losses are considered, including potential sorbent artefacts, possible breakthrough of volatiles through sampling tubes, or eventual losses of semi-volatiles due to their incomplete desorption or re-condensation inside the TG Analyser. The method is optimised and validated for di- to hexa-chlorinated benzenes in a range of 10-1000 ppb with average recovery exceeding 85%. The results are compared with data obtained in similar studies, performed by other research groups. As a result, the method provides the means for simulating de novo synthesis of dioxins in fly-ash and facilitates reliable and easy estimation of de novo activity, comparable with results of other studies, in combination with wide flexibility of testing conditions.