Penicillinase optodes: substrate determinations using batch, continuous flow and flow injection analysis operation conditions

Sensitive Electrochemical Penicillin Sensor Based on Screen‐printed Carbon Electrode Modified with Dendrimer‐encapsulated Pt Nanoparticles

“…Penicillin is a group of antibiotics classified specifically as β‐lactam antibiotics due to the presence of a β‐lactam ring in its molecular structure, and has been widely used since its discovery in 1928 . The facile analysis of penicillin has thus been of importance in various fields of applications including medical science, medicine, pharmaceutical industry, food industry, and environmental monitoring . Several sensing strategies have been developed for the detection of penicillin; they can be categorized mainly into three general approaches.…”

Optical fibre biosensors based on immobilised enzymes

“…For example, pnitrophenyl phosphate can be detected using alkaline phosphatase alone, 76 since in the following enzymatic reaction, a coloured p-nitrophenoxide product is generated and can be readily detected using optical fibres. Similarly, only penicillinase (or b-lactamase) is needed for the measurement of penicillin G 13,23,29,[80][81][82][83] since in this biocatalysed reaction, penicillinoic acid (pK a ~3.0) is produced and this can be easily detected by using a fibre optic pH optode.…”

“…Fig 10. Examples of enzyme membrane designs for optical fibre sensors: A, nylon net held by an O-ring;76 B, controlled pore glass glued to fibre-tip;80 C, internal enzyme solution enclosed by a gas-permeable membrane; 20 D, enzyme nylon membrane covering an indicator; 44 E, crosslinked-enzyme over carbon black and silicone-indicator layer; 42 F, nylon membrane held by a screw cap;7 and G, poly(acrylamide) gel coated on a glass slide and containing entrapped enzymes 83. …”

Theory and Practice of Rapid Flow-Through Analysis Based on Optode Detection and Its Application to pH Measurement as a Model Case

“…The combination of FIA with an optode has already been reported by us and others. − Most of these papers, however, deal only with sensor response characteristics; no discussion is provided about the importance of the flow system. Though its application technique is important for the practical use of optodes, unfortunately, the theoretical and experimental response performances of optodes in a flow system have not been clearly discussed in the past.…”

“…pH-sensitive optodes have been actively investigated for their potential in practical use such as clinical analysis, environmental analysis, and process control. They could be used not only for simple pH sensing but also for the sensing of acidic and alkaline gas species such as CO 2 and NH 3 . − Enzyme-based biosensing optodes could also be prepared based on pH-sensitive optodes in which they measure pH change by monitoring protons generated or consumed by the enzyme reaction. ,,− , These pH optodes mostly utilize pH indicator dyes, in which several kinds of dye immobilizations in the bulk optode sensing phase were reported with unique techniques such as trapping in dialysis tubing, adsorbing in polymer beads, covalently immobilizing onto porous glass or a cellulose membrane, , and ionically immobilizing onto an anion-exchange resin or sulfonated polystyrene surface. , Among them, the covalent bonding immobilization of pH indicator dyes is the most effective in terms of a long optode lifetime, but this immobilization technique has not been fully established although it has been continuously investigated.…”