Figure 8
Schematic diagram of the flow injection chemiluminescence system. a: Luminol + SCC; b: sample or blank solution; c: H 2 O 2 ; P: Pump; V, injector; F, flow cell; AMP, amplifier; w, waste; HV, high voltage; PMT, photomultiplier tube; PC, computer.
Source publication
Carbamates weaken the luminol-H 2 O 2 chemiluminescence (CL) catalyzed by sodium copper chlorophyll (SCC). The capacity to inhibit the CL of three carbamates is in the order of carbaryl (CBL) >carbofuran (CBF) >metolcarb (MTC). Mechanisms of carbamates inhibiting SCC-luminol-H 2 O 2 CL are investigated using fluorescence quenching and quantum chemi...
Context in source publication
Context 1
... shown in Figure 8, the FI configuration consisted of a three-channel manifold where either standards or sample solutions were incorporated into a H 2 O 2 solution carrier with the aid of a manual injection valve. Prior to the CL measurement acquisition corresponding to solutions containing SCC, the alkaline luminol solution stream was mixed with the carbamate sample or blank solution stream in a three-way T connector. ...
Citations
Convenient and rapid detection of Cu²⁺ in serum has important clinical significance for related diseases. Herein, a ratiometric detection of Cu²⁺ based on specific short peptide (SPGH)-assisted enhanced chemiluminescence resonance energy transfer (CRET) has been constructed. An interesting phenomenon that tetra-peptide with the sequence of Ser-Pro-Gly-His (SPGH) was able to specifically and remarkably enhance the catalytic performance of Cu²⁺ has been discovered, the enhancement mechanism is mainly due to the significant increasing generation of Cu²⁺-induced hydroxyl radical after addition of SPGH. The chemiluminescence (CL) of the luminol-H2O2 system was efficiently catalyzed by the formed Cu(SPGH)2 complex, which acts as an internal light source to triggers on the fluorescence of QDs via CRET, allowing the ratiometric detection of Cu²⁺ within 15 min with improved selectivity and sensitivity. The relative standard deviation was lower than 6.38 % due to the ratiometric signal improving its anti-interference ability. Importantly, it is feasible to detect total Cu in human serum, and the results were consistent with that of ICP-AES (r = 0.9321, n=55). The reliable, rapid, yet simple ratiometric detection of Cu²⁺ in serum based on SPGH-assisted enhanced CRET provides a promising potential alternative method for Cu²⁺ detection in clinical application.
For aqueous two-phase extraction (ATPE), adsorbents such as primary secondary amine (PSA) are usually used to remove fat and protein in meat samples. However, it was determined that PSA adsorbed approximately 5% of measured sulfonamides (SAs), which is the reason for the low recovery rate. To overcome this adverse PSA effect, a solid phase extraction (SPE) method was used for purification and enrichment after the formation of aqueous two-phase. Based on these, A new aqueous two-phase sample pretreatment method with solid phase extraction (ATP-SPE) to detect sulfonamides in fish meat is proposed. Fluorescence quenching showed that for 6 SAs, hydrogen bonding and van der Waals force played the major role in the binding reaction with fish serum albumin protein. In addition, in the 80% ACN aqueous solution, a slow protein denaturation took place and the drugs bound with the protein were released, which is more conducive to the aqueous two-phase extraction. In order to obtain better separation effect, the factors for synthesis of hydrophobic-lyophobic balance (HLB) packing for SPE were explored. Stirring speed is the most important factor affecting the particle size of microspheres. After purification and enrichment by SPE, samples were directly analyzed by HPLC. The analytical process was validated in the fish sample matrix by the analysis of spiked blank samples. The mean recoveries of this method were 80.1–95.1% with RSD values of 1.37–3.95%. The detection limits were 5.8–11.7 ng/g. The new ATP-SPE pretreatment method provides a new way for better recovery of veterinary drugs in meat products.
