Abstract
This study presents the application of a simultaneous method for the determination of total organic carbon (TOC) and total nitrogen (TN) in marine sediments and soils, using a data set of 206 samples collected from coastal lagoonal/marine sedimentary environments and certified reference materials (CRMs). TOC and TN were determined using the high temperature (720°C) catalytic (Pt/Al2O3) oxidation method and the detection of TOC and TN was performed using an infrared or a chemiluminescence detector, respectively. Results from the abovementioned TOC method were compared with the results from the widely used Wakley-Black titration method, while TN results with these from elemental analysis. Analytical quality control experiments were performed using CRM samples. Method characteristics such as range of measurement, calibration, method detection limit (MDL), limit of quantification (LOQ), repeatability and reproducibility, were calculated. The precision and the accuracy of the methods are also discussed. Comparison of the two TOC methods of 206 data set yields a regression line of correlation coefficient with R2 = 0.985. Additional different levels of TOC concentrations of low <1%, moderate 1–5% and high 5–40% level were examined indicating very good correlations. The lowest correlation coefficient was observed in low concentrations TOC<1% (R2 0.825), mainly as a result of the limitation of titration method. The evaluation of TN results indicated that the catalytic oxidation method and the elemental analysishave a significant good correlation with R2 = 0.977. The results of precision and accuracy, as well as the calculated MDL and LOQ show that this is a reliable method. Moreover, it requires a small amount of the analyzed sample and the total analysis time is 10 min. Therefore, it can be easily applied for the fast and precise simultaneous determination of TOC and TN in sediment and soil samples.
Highlights
Total organic carbon (TOC) and total nitrogen (TN) are important parameters for assessing the environmental status of terrestrial and aquatic ecosystems
As it is extensively presented in our previous publication [35], the calibration curves for all parameters were constructed by measuring ten standard solutions with concentrations covering the full range of the measurement area (0.1 mg/L, 0.2 mg/L, 0.5 mg/L, 1 mg/L, 2 mg/L, 5 mg/L, 10 mg/L, 20 mg/l, 50 mg/L and 100 mg/L)
The characteristic calibration curves used for the total carbon (TC), inorganic carbon (IC) and TN analyses in this work are shown in Fig 2 and as we can see in all cases we have satisfactory linear graphs (R2 0.995)
Summary
Total organic carbon (TOC) and total nitrogen (TN) are important parameters for assessing the environmental status of terrestrial and aquatic ecosystems. The organic carbon and nitrogen in soils and sediments are mainly coming from decomposition of the animals and plants Anthropogenic sources such as chemical impurities, fertilizers or organic-rich wastes, enrich the ecosystems with organic carbon and nitrogen. Both TOC and TN are often used as an index of the available amount of food to benthic animals. Both are used in aquatic systems as an important index of the organic load settling to the bottom sediments from the water column. The presence of TOC and TN affect the faunal communities as it is crucial for the primary production which is a key issue for the eutrophication status
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
