TY  - JOUR
AB  - Interlaboratory comparison on the determination of the molecular composition of humic substances (HS) was undertaken in the framework of IUPAC project 2016-015-2-600. The analysis was conducted using high resolution mass spectrometry, nominally, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization. Six samples of HS from freshwater, soil, and leonardite were used for this study, including one sample of humic acids (HA) from coal (leonardite), two samples of soil HA (the sodpodzolic soil and chernozem), two samples of soil fulvic acids (FA) (the sod-podzolic soil and chernozem), and one sample of freshwater humic acids (the Suwannee River). The samples were analyzed on five different FTICR MS instruments using the routine conditions applied in each participating laboratory. The results were collected as mass lists, which were further assigned formulae for the determination of molecular composition. The similarity of the obtained data was evaluated using appropriate statistical metrics. The results have shown that direct comparison of discrete stoichiometries assigned to the mass lists obtained by the different laboratories yielded poor results with low values of the Jaccard similarity score - not exceeding 0.56 (not more than 56 % of the similar peaks). The least similarity was observed for the aromatics-rich HA samples from leonardite (coal) and the chernozem soil, which might be connected to difficulties in their ionization. The reliable similarity among the data obtained in this intercomparison study was achieved only by transforming a singular point (stoichiometry) in van Krevelen diagram into a sizeable pixel (a number of closely located stoichiometries), which can be calculated from the population density distribution. The conclusion was made that, so far, these are descriptors of occupation density distribution, which provide the metrics compliant with the data quality requirements, such as the reproducibility of the data measurements on different instruments.
AU  - Zherebker, A.*
AU  - Kim, S.*
AU  - Schmitt-Kopplin, P.
AU  - Spencer, R.G.M.*
AU  - Lechtenfeld, O.*
AU  - Podgorski, D.C.*
AU  - Hertkorn, N.
AU  - Harir, M.
AU  - Nurfajin, N.*
AU  - Koch, B.*
AU  - Nikolaev, E.N.*
AU  - Shirshin, E.A.*
AU  - Berezin, S.A.*
AU  - Kats, D.S.*
AU  - Rukhovich, G.D.*
AU  - Perminova, I.V.*
C1  - 60539
C2  - 49358
CY  - Genthiner Strasse 13, D-10785 Berlin, Germany
SP  - 1447–1467
TI  - Interlaboratory comparison of humic substances compositional space as measured by Fourier transform ion cyclotron resonance mass spectrometry (IUPAC Technical Report).
JO  - Pure Appl. Chem.
VL  - 92
IS  - 9
PB  - Walter De Gruyter Gmbh
PY  - 2020
SN  - 0033-4545
ER  - 

TY  - JOUR
AB  - The general population is increasingly exposed to cerium (Ce), which is contained in industrial products or is present as nuclear Ce fission products. Some studies suggested a link between elevated Ce levels and endomyocardial fibrosis. Since breast milk is the optimal, and directly after birth, usually the sole nutrition for newborns, exposure of females to Ce and its transfer to infants by breast-feeding is of concern in neonate protection. Consequently, the transfer rate of Ce from blood to breast milk is of interest for elucidating the Ce exposure of infants. Biomonitoring of paired serum and breast milk samples provides such information about Ce transfer to human milk. Therefore, this study is aimed at clarification of the relationship between Ce in human milk and serum from respective mothers for elucidating Ce enrichment in human milk with possible nutritional risk for newborns. As a prerequisite a strictly quality-controlled Ce determination method applicable to very low Ce concentration was developed, and its figures of merit were determined and found to be sufficient for our purpose. It turned out that Ce concentration in milk from Munich (Germany) and Madrid (Spain) showed a median of 13 ng/L. Ce concentrations in serum were at limit of quantification (LOQ) 10 ng/L (Munich) or 21.6–70.3 ng/L (Madrid), suggesting a higher Ce intake in Madrid. No enrichment from blood to milk was seen, and no elevated nutritional risk for breast-fed babies from Ce was found. Ce in serum, but not in milk, could indicate environmental Ce.
AU  - Michalke, B.
AU  - González-Estecha, M.*
AU  - Trasobares, E.M.*
AU  - Herraiz, M.A.*
AU  - Giussani, A.
AU  - Oeh, U.
AU  - Höllriegl, V.
C1  - 7152
C2  - 29492
SP  - 313-324
TI  - Cerium in human milk samples and its transfer from blood to milk: Is there an elevated nutritional risk for breast-fed babies?
JO  - Pure Appl. Chem.
VL  - 84
IS  - 2
PB  - International Union of Pure and Applied Chemistry
PY  - 2012
SN  - 0033-4545
ER  - 

TY  - JOUR
AU  - Michalke, B.
C1  - 4316
C2  - 23457
SP  - 79-90
TI  - Trace element speciation in human milk.
JO  - Pure Appl. Chem.
VL  - 78
PY  - 2006
SN  - 0033-4545
ER  - 

TY  - JOUR
AU  - Lintelmann, J.
AU  - Katayama, A.*
AU  - Kurihara, N.*
AU  - Shore, L.*
AU  - Wenzel, A.*
C1  - 9921
C2  - 21062
SP  - 631-681
TI  - Endocrine Disruptors in the Environment. 
JO  - Pure Appl. Chem.
VL  - 75
PY  - 2003
SN  - 0033-4545
ER  - 

TY  - JOUR
AU  - Marth, P.
AU  - Martens, D.
AU  - Schramm, K.-W.
AU  - Schmitzer, J.
AU  - Oxynos, K.
AU  - Kettrup, A.
C1  - 21435
C2  - 19552
SP  - 1027-1034
TI  - Environmental specimen banking. Herring gull eggs and breams as bioindicators for monitoring long-term and spatial trends of chlorinated hydrocarbons.
JO  - Pure Appl. Chem.
VL  - 72
PY  - 2000
SN  - 0033-4545
ER  -