Fluorescence sensing of chromium (VI) and ascorbic acid using graphitic carbon nitride nanosheets as a fluorescent “switch”

Study on the Ultrahigh Quantum Yield of Fluorescent P,O‐g‐C3N4 Nanodots and its Application in Cell Imaging

“…[27,28] The P, O-g-C 3 N 4 nanodots were the smallern anodots produced during acid oxidation and hydrothermale tchingo ft he bulk P-g-C 3 N 4 .S imilart ot he g-C 3 N 4 nanosheets derived from acid oxidation, the acid oxidation process introduces many oxygen-containing groups,s uch as hydroxyl and carboxyl, on the surfacea nd edges of the bulk P-g-C 3 N 4 sheets. [17,29] To investigate the effect of the degree of phosphorus doping on the structure and opticalp roperties of the P, O-g-C 3 N 4 nanodots, the hydrothermal process wasf irst carried out at 200 8C for 20 ho na ll the acid-oxidized1 -30 %P-g-C 3 N 4 sheets.A s shown in Figure 1, all the P, O-g-C 3 N 4 appeared ass pherelike nanodotsw ith size smaller than 10 nm. The acid-oxidized g-C 3 N 4 sheets( thick creamy liquid)w ere decomposed into ammonia and water during the high-temperature hydrothermal process.…”

“…[11] Because the bulk structure of g-C 3 N 4 inhibits its development in nanotechnology andb iology,g -C 3 N 4 nanosheets/nanodots have been explored and applied in sensing, biosensing, and bioimaging. [12][13][14][15][16][17][18] However, the studies on g-C 3 N 4 nanodots( < 10 nm) are still in their early stage.U pt on ow,e xcept for our previousr eport, [19] no QY of g-C 3 N 4 nanodots surpassing 50 %h as been reported.T he QY of g-C 3 N 4 nanodotsi sm uch lower than that of fluorescent dyes and semiconductor QDs and inhibits their versatile application in photoelectronics and biomedical devices. [20] Therefore, exploration of novel,h ighly fluorescent g-C 3 N 4 nanodotsw ith high QY is urgently required.…”

A fluorescence turn-off-on chemosensor based on carbon nanocages for detection of ascorbic acid

“…This detection limit is not only far below that obtained by HPLC, 10 ame atomic absorption spectrometry 11 and the electrochemical method, 8 but also less than other forms of uorescence spectroscopy. 15,17,37 Therefore, this method based on using CNCs-Fe 3+ as a probe has high sensitivity, a very low detection limit and excellent precision for quantitative detection of AA. The selectivity of the CNCs-Fe 3+ for the detection of AA was explored in the presence of other possible reducing agents.…”

“…34 It is also well known that AA is a strong reducing agent which is stabilized by electron delocalization and exists in mono-anionic form (AH À ). 37 Therefore, it can easily attack the positively charged Fe 3+ and reduce the oxidation state of the cations from Fe 3+ to Fe 2+ . As a result, the complexation between Fe 3+ and the CNCs will be disrupted, leading to the recovery of the CNCs' uorescence.…”

Detection of Ascorbic Acid Using Green Synthesized Carbon Quantum Dots

“…Ascorbic acid (vitamin C, AA) plays a crucial role as an essential nutrient and antioxidant in the human body, which exists only in food and drugs and cannot be synthesized by human beings themselves. The abnormal concentration of AA can be related to various kinds of diseases including scurvy, mental disorder, cancer, cold, AIDS, and digestive disorder [1][2][3][4][5]. In addition, AA has been found to participate in a lot of life processes, such as cell division, iron absorption, acceleration of collagen synthesis, melanogenesis inhibition, and metabolism [6][7][8][9].…”