Discriminant analysis of pyrrolizidine alkaloid contamination in bee pollen based on near-infrared data from lab-stationary and portable spectrometers

Bee pollen may be contaminated with pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs), which are mainly detected by liquid chromatography coupled to tandem mass spectrometry (LC\u2013MS/MS), even though the use of fast near-infrared (NIR) spectroscopy is an ongoing alternative. Therefore, the main challenge of this study was to assess the feasibility of both a lab-stationary (Foss) and a portable (Polispec) NIR spectrometer in 60 dehydrated bee pollen samples. After an ANOVA-feature selection of the most informative NIR spectral data, canonical discriminant analysis (CDA) was performed to distinguish three quantitative PA/PANO classes (\ub5g/kg): 400, high. According to the LC\u2013MS/MS analysis, 77% of the samples were contaminated with PAs/PANOs and the sum content of the 17 target analytes was higher than 400\ua0\ub5g/kg in 28% of the samples. CDA was carried out on a pool of 18 (Foss) and 22 (Polispec) selected spectral variables and allowed accurate classification of samples from the low class as confirmed by the high values of Matthews correlation coefficient ( 65 0.91) for both NIR spectrometers. Leave-one-out cross-validation highlighted precise recognition of samples characterised by a high PA/PANO content with a low misclassification rate (0.02) as false negatives. The most informative wavelengths were within the 2400\ua0nm regions for Foss and > 1500\ua0nm for Polispec that could be associated with cyclic amines, and epoxide chemical structures of PAs/PANOs. In sum, both lab-stationary and portable NIR systems are reliable and fast techniques for detecting PA/PANO contamination in bee pollen

Determination of total organic carbon - an overview of current methods

This article summarizes the most important and current methods for the determination of total organic carbon (TOC) in solid samples. The methods presented are chemical oxidation, combustion, acid treatment and ashing. We discuss the advantages of the different methods as well as problems that can be encountered during analysis. We give additional information on the detection techniques used for TOC determination and on the topic of volatile organic carbon (VOC) that deserves particular attention when carrying out TOC determinations, in particular with solid samples. We have compiled a concise survey of the literature covering 60 reports and tabulated the relevant analytical parameters. (C) 2004 Elsevier Ltd. All rights reserved. [References: 60

Duale Temperatur-Verbrennung (DTV) im Einsatz : analytische Bestimmung des organischen Kohlenstoffs (OC) in Bodenproben

Eine verlässliche Methode zur Bestimmung von anorganischem, organischem und Gesamt-Kohlenstoff in Bodenproben in einem analytischen Schritt wird vorgestellt. Hierbei werden mittels eines dynamischen Heizers der anorganische und organische Kohlenstoff bei zwei unterschiedlichen Temperaturen bestimmt. Die Methode wurde auf 5 verschiedene Bodenproben mit bekanntem Kohlenstoff-Gehalt angewendet und mit der „klassischen“ Säuremethode nach DIN 10694 verglichen. Sie eignet sich sehr gut zur Bestimmung von OC, IC und T

A novel single-run dual temperature combustion (SRDTC) method for the determination of organic, in-organic and total carbon in soil samples

The quantification of organic (OC) and inorganic carbon (IC) in soils provides an essential tool for understanding biogeochemical processes. Examples of its potential application are the assessment of the humification degree of soil organic matter, the calculation of carbon fluxes and budgets in terrestrial systems on a regional and global scale and the investigation of the carbon storage potential of soils. The verification of changes in carbon stocks requires an extensive number of samples as well as precise and reliable analyses. Due to the wide variation in the concentrations of the two forms of carbon in solid samples, the exact distinction is very difficult. We present the advantages of a single-run dual'temperature combustion method (SRDTC) at 515 degrees C for OC and 925 degrees C for IC, which allows the determination of OC, IC and total carbon (TC) within one single analytical run. The three parameters are analyzed in less than 30 min. Additionally, the method is characterized by a significantly reduced variability and low operator bias, as there is no need of chemical sample pre-treatment. It is applicable to a broad range of varying OC and IC contents, which is demonstrated by the use of numerous synthetic soil mixtures that have been analyzed. Furthermore, SRDTC indicates the presence of thermally instable carbonates, like magnesite, in the sample. Use of silver boats as a catalytic agent results in an improved distinction between OC and IC in this case. To examine the accuracy and reliability of the SRDTC method, it was compared to other techniques frequently used for carbon determination in soil samples: total combustion by elemental analysis to determine TC and acidification of the sample prior to combustion to determine OC. We will show that the rugged SRDTC method offers a substantial progress for both the reliable and rapid OC and IC determination in soil samples where elemental carbon is negligible. (c) 2006 Elsevier B.V. All rights reserved. [References: 26

Digital corporate identity congruence analises: highlighting critical issues and untapped opportunities. A focus on Italian SMEs of the dairy industry

Firms often signal their identities through their digital footprints. The context chosen for this research is the Italian dairy industry, which is fragmented with many product-oriented smaller farms. Corporate identity congruence (CIC) refers to the fit between several corporate identity meanings. These meanings are signaled to stakeholders by multiple vehicles, some of which are digital in nature. Digital signal analyses could reveal misalignment between offline and online communication. The research design involves multiple studies: phenomenological interviews on 7 case studies, using NVIVO to analyze transcripts and other documents; nutritional and chemometric analysis on dairy products; corporate identity congruence meaning based analysis, with a particular focus on digital communication. Misalignments discovered between what companies do, who they are, and what they say (offline and online) are discussed as critical issues. This digital CIC analysis strives to highlight new opportunities for companies that want to evolve their digital corporate identit