Please note that we do not accept samples outside our faculty. When our lab personnel has the capacity, we may analyze samples from our faculty. Prior processing of solid samples, e.g. plant and soil, have to be done by the persons themselves such that samples are already in liquid form for our chemical analysis.

Please consult first with Dr. Marife D. Corre if there is a present capacity for samples outside our group but within our faculty, and for the fee to cover consumable costs.

• Total extractable N, NH₄⁺, NO₃^- in soils (with 0.5 M K₂SO₄ extraction), and PO₄^3-, SO₄^2- and Cl^- in water samples, using continuous flow injection colorimetry (SEAL Analytical AA3, SEAL Analytical GmbH, Norderstedt, Germany). Total N is determined by ultraviolet-persulfate digestion followed by hydrazine sulfate reduction (Autoanalyzer Method G-157-96), NH₄⁺ by salicylate and dicloro isocyanuric acid reaction (Autoanalyzer Method G-102-93), and NO₃^- by cadmium reduction method with NH₄Cl buffer (Autoanalyzer Method G-254-02). PO₄^3- is determined by reaction with molybdate, antimony and ascorbic acid to produce phosphate-molybdenum blue complex (Autoanalyzer Method G-092-93). SO₄^2- is determined by reaction with barium chloride and methylthymol blue to produce a blue chelate complex (Autoanalyzer Method D-061-92). Cl^- is determined with an ion strength adjustor reagent that is pumped through an ion-selective chloride electrode with an integrated reference electrode (autoanalyzer method G-329-05).
  
  
  
  
• Organic C from soil extracts (with 0.5M K₂SO₄ solution) and water samples, using a Total Organic Carbon Analyzer (TOC-Vwp, Shimadzu Europa GmbH, Duisburg, Germany). Organic C is analyzed by pre-treating the samples with H₃PO₄ solution (to remove inorganic C) followed by UV-enhanced persulfate oxidation of organic C to CO₂ and analyzed by an infrared detector.
  
  
  
  
• Soil exchangeable (using cation exchange method by percolation with 1M NH₄Cl solution) elements (e.g. Na, K, Ca, Mg, Fe, Al, Mn), plant and soil total (using pressure digestion in concentrated HNO₃) elements (e.g. Na, K, Ca, Mg, Fe, Al, Mn, P, S, Ni, Cu, Pb, etc.) and specific elements (e.g. Fe, Al, P, etc.) from other soil-extraction methods (e.g. ammonium oxalate, pyrophosphate, resin, Bray, sodium bicarbonate) using inductively coupled plasma-optical emission spectrometer (iCAP Pro ICP-OES, Thermo Fischer Scientific GmbH, Dreieich, Germany).
  
  
  
  
• N₂O, CO₂, CH₄, C₂H₂ and C₂H₄ concentrations (with gas samples stored in 12-ml glass vials; Exetainer; Labco Limited, Lampeter, United Kingdom) using a gas chromatograph (SRI 8610C, SRI Instruments Europe GmbH, Bad Honnef, Germany) equipped with a flame ionization detector (for CO₂ with a methanizer, CH₄, C₂H₂ and C₂H₄), an electron capture detector (for N₂O with a make-up gas of 5%CO₂-95%N₂ (5.0 purity grade)), and an autosampler.