Nitrogen-doped carbon dots were applied in the fluorescence detection of Cu2+ and electrochemical detection of BPA.

An accurate quantitative and confirmative method has been developed for the deter- mination of eight fluorescent whitening agents (FWAs) in textile by ultra performance conver- gence chromatography (UPC2) coupled with photo diode array (PDA) detection, including 1,2-bis (5-methyl-2-benzoxazole) ethylene (PF), 7-diethylamino-4-methylcoumarin (SWN), 2, 2'-(2,5-thiophenediyl) bis(5-(1,1-dimethylethyl)-benzoxazol (OB), 2-[4-[2-[4-(2-benzox- azolyl) phenyl] ethenyl] phenyl] -5-methyl-benzoxazol (KSN), 1,4-bis (2-cyanostyryl) benzene (ER-I), 1-(2-cyanostyryl)-4-(4-cyanostyryl) benzene (ER-II), 2,2'-(1,4-naphthalenediyl) bis-benzoxazol (KCB), 4,4'-bis[2-(2-methoxyphenyl) ethenyl]-1,1'-biphenyl (FP). The sample was extracted with xylene and concentrated by a rotary evaporator, and then qualitatively and quantitatively analyzed by UPC2. The separation of target compounds was achieved on an ACQUITY UPC2 HSS C18 SB column (100 mm x 3.0 mm, 1.8 μm) by a gradient elution with supercritical carbon dioxide and methanol as mobile phases. External standard method was used for the quantitative determination and the calibration curves showed good linearity in the concentration range of 1.0-20.0 mg/L for the eight target compounds with correlation coefficients not less than 0.999 1. The limits of quantification of the eight compounds (LOQs, S/N = 10) were 0.70-0.95 mg/L. The average recoveries of the eight compounds ranged from 90.9% to 96.5% at the spiked levels of 2.0, 5.0, 10.0 mg/kg with the relative standard deviations (RSDs) of 2.8%-4.2%. The method is simple, accurate and time-saving with high sensitivity, and can be used for the rapid determination of the eight FWAs in textile.

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