Chromium hollow cathode lamp

For determination of chromium atomic absorption spectrometry with atomization in air-acetylene flame and deuterium, background correction (Solaar M6, Thermo Electron Corporation, UK) was used. The measurements of chromium were performed at wavelength λ = 357.9 nm with a slit of 0.5 nm by using a chromium hollow cathode lamp (Photron, Australia) operated at 6-mA current.
The FT-IR absorption spectrum of polymer (4000–500 cm⁻¹) in KBr was recorded using Thermo Nicolet Magna IR 550 Series II (Nicolet, Japan). Surface area of the polymer was measured by Brunauer, Emmett and Teller (BET) method using surface area and porosity analyzer Gemini VII 2390 (Micrometrics, USA). A scanning electron microscope SEM Inspect S50 (Hitachi, USA) was used for studies of morphology of polymer particles.
A SPE system consisting of laboratory-made glass adsorption column (internal diameter (i.d.) 9 mm) filled with 0.1 g of the polymer, PTFE tubing of i.d. 0.8 mm and a peristaltic pump Minipuls 3 (Gilson, France) was used.
The pH values of solutions were controlled with an inoLab pH Level 1 pH meter (WTW, Germany) equipped with an electrode SenTix 21 (WTW, Germany).

A Solaar M6 (Thermo Electron Corporation, UK) atomic absorption spectrometer equipped with a Zeeman-effect background correction system and an electrothermal atomizer (ELC graphite tubes) was used for chromium determination. A chromium hollow cathode lamp (Photron, Australia) was operated at 15 mA. The measurements were done at λ = 357.9 nm with a spectral bandpass of 0.5 nm. The following optimised heating programme was used to determine chromium in the soil extracts: drying at 110 °C for 15 s, ashing at 1200 °C or 1650 °C for 8 s, and atomisation at 2600 °C for 3 s. A temperature of 1650 °C was used to ash extracts containing K₂HPO₄ in the presence of Mg(NO₃)₂ (10 μL of 10 μg mL⁻¹, 0.1 μg) as a chemical modifier. An inoLab pH Level 1 (WTW, Germany) pH meter equipped with a SenTix 21 electrode (WTW, Germany) was used for the pH measurements. A Shimadzu SSM-5000A TOC Analyser was used to determine the carbon content in the soil by catalytically aided combustion oxidation method. A ball mill (KM 1 type K142, MLW, Poland) was used for soil grinding.