Toward the Standardization of Biochar Analysis: The COST Action TD1107 Interlaboratory Comparison.

Biochar produced by pyrolysis of organic residues is increasingly used for soil amendment and many other applications. However, analytical methods for its physical and chemical characterization are yet far from being specifically adapted, optimized, and standardized. Therefore, COST Action TD1107 conducted an interlaboratory comparison in which 22 laboratories from 12 countries analyzed three different types of biochar for 38 physical-chemical parameters (macro- and microelements, heavy metals, polycyclic aromatic hydrocarbons, pH, electrical conductivity, and specific surface area) with their preferential methods. The data were evaluated in detail using professional interlaboratory testing software. Whereas intralaboratory repeatability was generally good or at least acceptable, interlaboratory reproducibility was mostly not (20% < mean reproducibility standard deviation < 460%). This paper contributes to better comparability of biochar data published already and provides recommendations to improve and harmonize specific methods for biochar analysis in the future.

Low cost methodology for estrogens monitoring in water samples using dispersive liquid-liquid microextraction and HPLC with fluorescence detection.

A new low cost methodology for estrogens' analysis in water samples was developed in this work. Based on dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection, the developed method is fast, cheap, easy-to-use, uses low volumes of organic solvents and has the possibility of a large number of samples to be extracted in parallel. Under optimum conditions (sample volume: 8 mL; extraction solvent: 200 µL of chlorobenzene; dispersive solvent: 2000 µL of acetone), the enrichment factor and extraction recoveries were 145 and 72% for 17ß-estradiol (E2) and 178 and 89% for 17α-ethinylestradiol (EE2), respectively. Limits of detection of 2.0 ng L(-1) for E2 and 6.5 ng L(-1) for EE2 were achieved, allowing the detection and quantification of these compounds in surface and waste water samples with concentrations from 12 to 32 ng L(-1) for E2 and from 11 to 18 ng L(-1) for EE2. Also, recovery tests were performed to evaluate possible matrix effects. Recoveries between 98% and 106% were obtained using humic acids (HA) to simulate the effect of organic matter, and between 86% and 120% in real water samples.

Development and application of a capillary electrophoresis based method for the assessment of monosaccharide in soil using acid hydrolysis.

An efficient methodology for the determination of carbohydrate content in soils, employing acid hydrolysis and subsequent capillary electrophoresis analysis (CE), is here described. Polysaccharides present in soil samples were hydrolyzed, at 100 degrees C during 4h, to their monosaccharide form, by addition of 2moldm(-3) trifluoroacetic acid (TFA) directly to soil. The resulting monosaccharides were then quantitatively derivatized with 4-aminobenzoic acid ethyl ester, via reductive amination with sodium cyanoborohydride, and separated by CE, coupled to an UV-vis diode array set at 300nm. Separation electrolyte consisted of 5.0x10(-2)moldm(-3) sodium tetraborate buffer (pH 10.2) and 6x10(-3)moldm(-3) sodium dodecylsulphate. A 78cm long capillary with an internal and external diameter of 75 and 375mum, respectively, was used and separation performed at 16 degrees C, with an applied voltage of 30kV. Quantification was undertaken using ribose as the internal standard. As an application example, carbohydrate composition (w/w) of a farmyard manure fertilized soil was found to vary between 0.0045+/-0.0003% (glucose) and 0.0267+/-0.0002% (arabinose) of the total soil content. Xylose, rhamnose, mannose, fucose and galactose content were also studied in the present work.