Trace Determination of Tetranitrocarbazole in Aquatic Environment Using Carbon Dot-Dispersive Liquid-Liquid Microextraction Followed by UV-Vis Spectrophotometry

An efficient carbon dot-dispersive liquid-liquid microextraction followed by UV-Vis spectrophotometry (CD-DLLME-UV-Vis) has been effectively developed for the sensitive determination of 1,3,6,8-tetranitrocarbazole (TNC) in environmental water samples. In this DLLME-based method, home-made syntheses carbon dots (CDs) were directly extracted into carbon tetrachloride using trioctylmethylammonium chloride (aliquat 336), which works as a disperser agent. By applying inherent colorimetric feature, the enriched CDs exhibited an intensive absorption signal at 300 nm, which swelled up in the presence of TNC due to their interaction at the colloidal interface. Main parameters that controlling and affecting the performance of the microextraction process were evaluated and optimized in details. An enrichment factor of 55.5 beside a meaningful sample clean-up was achieved under the optimized conditions. The calibration curve was linear in the range of 1-200 ng mL-1 with regression coefficient corresponding to 0.999. Limit of detection (S/N = 3) was 0.2 ng mL-1 while the RSD% values (n = 10) for the target analyte at two concentration levels of 20 and 100 ng mL-1 were 3.6 and 1.7, respectively. The proposed method was ultimately exerted for the preconcentration and determination of TNC in various environmental water samples and admissible results were achieved.