Determination of total organic carbon – an overview of current methods

Groundwater-induced redox-gradients control soil properties and phosphorus availability across four headwater wetlands, New York, USA

“…Dried samples were homogenized for additional soil analyses by grinding with a mortar and pestle and passing the soil through a 2 mm sieve to exclude roots. Organic matter content was estimated by mass loss-on-ignition after combustion in a muffle furnace at 520°C for 2 h (Carter 1993) assuming that the relatively low temperature oxidized only organic carbon (Bisutti et al 2004). Total elemental content was determined by hydrofluoric digestion and subsequent analysis by inductively-coupled plasma atomic emission spectrometry (US-EPA Method 3052) (U.S. Environmental Protection Agency 1996).…”

Carbonate removal from coastal sediments for the determination of organic carbon and its isotopic signatures, δ13C and Δ14C: comparison of fumigation and direct acidification by hydrochloric acid

“…The drawbacks to using HCl are the production of hygroscopic salts (e.g., CaCl 2 , MgCl 2 ) which increases the sample drying time, and the introduction of chloride into the sample which could cause difficulties with instrumental analyses. Finally, it should be noted that for all acids mentioned above, there are reports of organic matter loss during carbonate removal (Heron et al 1997;King et al 1998;Lohse et al 2000;Bisutti et al 2004). Although the mechanisms for organic matter loss are unclear, they may include loss of acid volatiles, decarboxylation, oxidation, and spills.…”

“…While the accuracy of %OC obtained by different IC removal methods has been a topic of considerable discussion (e.g., review by Bisutti et al 2004), much less is known about the corresponding accuracy of the isotopic signatures of the isolated OC. This is problematic, because δ 13 C OC and Δ…”

“…Although the mechanisms for organic matter loss are unclear, they may include loss of acid volatiles, decarboxylation, oxidation, and spills. For HCl and H 2 SO 3 , heat may exacerbate organic matter loss (Bremner 1949;Bisutti et al 2004).…”

Determinação voltamétrica de metais em águas e fluidos biológicos empregando mineralização de amostras com radiação ultravioleta

“…13 Primeiramente ensaios envolvendo fotólise direta, ou seja, sem adição de H 2 O 2 como precursor radicalar, foram realizados para verificação de uma possível fotodegradação da amostra sem a influência de fatores extrínsecos ao sistema. Para estes ensaios não foi observada voltametricamente uma mineralização (fotodegradação) da amostra após 4 h de fotólise direta, evidenciando assim a fotoestabilidade da amostra.…”