Determination of ampicillin and amoxycillin by flow injection chemiluminescence method based on their enhancing effects on the luminol–periodate reaction

In this work, a new flow injection chemiluminescence method is described for the determination of ampicillin and amoxycillin. The method is based on the strong enhancing effects of these antibiotics on the luminol–periodate reaction. The present method allows the measurements of ampicillin in the range 0.02–1.0 mg/L range and amoxycillin in the range 0.1–10.0 mg/L range with the relative standard deviations within 0.8–2.0%. The sampling frequency was calculated about 90/h. The method was successfully applied to the determination of ampicillin and amoxycillin in pharmaceutical preparations. A brief discussion on the possible chemiluminescence reaction mechanism is presented. Copyright © 2003 John Wiley & Sons, Ltd.     

Flow injection chemiluminescence determination of captopril based on its enhancing effect on the luminol–ferricyanide/ferrocyanide reaction

A new flow injection chemiluminescence method is described for the determination of captopril. It is based on the enhancing effect of captopril on the chemiluminescence reaction of luminol with potassium ferricyanide in alkaline solution in the presence of potassium ferrocyanide. The method allows the determination of captopril over 0.1–40 µg/mL range, with a relative standard deviation (SD) of 1.0% for the determination of 0.5 µg/mL captopril solution in 11 repeated measurements. The method was satisfactorily applied to the determination of captopril in commercial captopril tablets. The possible reaction mechanism is also discussed briefly. Copyright © 2002 John Wiley & Sons, Ltd.     

Post‐chemiluminescence determination of chloramphenicol based on luminol–potassium periodate system

A post‐chemiluminescence (PCL) phenomenon was observed when chloramphenicol was injected into a mixture of luminol and potassium periodate after the chemiluminescence (CL) reaction of luminol–potassium periodate had finished. The possible reaction mechanism was proposed based on studies of the CL kinetic characteristics, the CL spectra, the fluorescence spectra and the UV‐vis absorption spectra of the related substances. Based on the PCL reaction, a rapid and sensitive method for the determination of chloramphenicol was established. The linear response range was 6.0 × 10^?7–1.0 × 10^?5 mol/L, with a correlation coefficient of 0.9986. The relative standard deviation (RSD) for 5.0 × 10^?6 mol/L chloramphenicol was 2.3% (n = 11). The detection limit was 1.6 × 10^?7 mol/L. The method has been applied to the determination of chloramphenicol in pharmaceutical samples with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.     

DPPH·–luminol chemiluminescence system and its application in the determination of scutellarin in pharmaceutical injections and rat plasma with flow injection analysis

In this article, a DPPH·–luminol chemiluminescence (CL) system was reported and the CL mechanism was discussed according to the CL kinetic properties after sequence injecting DPPH· into the DPPH·–luminol reaction mixture. It was observed that scutellarin could inhibit the CL response of the DPPH·–luminol system. Based on this observation, a simple and rapid flow injection CL method was developed for the determination of scutellarin using the inhibition effect in alkaline medium. The optimized chemical conditions for the CL reaction were 5 × 10^?6 mol/L DPPH · and 1.0 × 10^?4 mol/L luminol in 0.01 mol/L NaOH. Under optimized conditions, the CL intensity was inversely proportional to the concentration of scutellarin over the ranges 5–2000 and 40–3200 ng/ml in pharmaceutical injection and rat plasma, respectively. The limits of detection (S/N  = 3) were 5 and 40 ng/ml in preparations and rat plasma, respectively. Furthermore, the precision, recovery and stability of the validated method were acceptable for the determination of scutellarin in both pharmaceutical injections and rat plasma. The presented method was successfully applied in the determination of scutellarin in pharmaceutical injections and real rat plasma samples.     

Flow injection chemiluminescence determination of isoniazid using the lucigenin-periodate system.

A weak chemiluminescence (CL) signal was observed during the mixing of isoniazid with lucigenin in alkaline aqueous solution. The CL signal was enhanced more than 100 times in the presence of potassium periodate. This CL system was developed for the determination of isoniazid using a flow injection mode. The CL intensity is proportional to the concentration of isoniazid in the range 0.005-1.0 mg/L. The limit of detection is 0.0034 mg/L and the relative standard deviation is 2.0% for 0.2 mg/L isoniazid solution in 11 repeated measurements. The method was applied to the determination of isoniazid in pharmaceutical preparations and satisfactory results were obtained.     

Flow-injection determination of carbaryl and carbofuran based on KMnO(4)-Na(2)SO(3) chemiluminescence detection.

A flow-injection method is described for the determination of carbaryl and carbofuran. It was found that a strong chemiluminescence (CL) signal was generated when these pesticides were mixed with Na(2)SO(3) and KMnO(4) in acidic medium. Under the optimum experimental conditions, the enhanced CL intensity was linear, with the concentrations in the range 0.1-2.0 microg/mL (r(2) = 0.9996 and 0.9993, n = 6) with relative standard deviation (n = 4) in the range 1.0-2.3%. The limits of detection (3sigma blank) were 10 and 50 ng/mL, respectively, with a sample throughput of 180/h. The proposed method was applied to determine carbaryl and carbofuran in freshwaters with satisfactory results. Most metal and non-metal ions and some pesticides, such as carbophenothion and aldicarb, do not interfere with the determination. Dinoseb, diazinon and malathion calibration graphs (in the range 0.2-2.0 microg/mL, r(2) = 0.9966-0.9988, n = 6) were also established with relative standard deviations (n = 4) in the range 1.2-2.0% with limits of detection (3sigma blank) in the range 100-300 ng/mL.     

Flow‐injection chemiluminescence determination of acetylsalicylic acid based on its enhancing effect on the lucigenin–hydrogen peroxide system

A sensitive flow‐injection chemiluminescence method for the determination of acetylsalicylic acid is described. It is based on the enhanced chemiluminescent emission of the alkaline lucigenin–H₂O₂ system by acetylsalicylic acid. The difference in chemiluminescent intensity of alkaline lucigenin–H₂O₂ in the presence of acetylsalicylic acid from that in the absence of acetylsalicylic acid was linear at acetylsalicylic acid concentrations in the range of 0.0029–47.37 µg/mL, with detection and quantification limits of 0.0011 and 0.0029 µg/mL_, respectively. The correlation coefficient of the working curve was 0.9983. The relative standard deviation (n = 10) for 25 µg/mL acetylsalicylic acid is 1.95%. All experimental parameters were optimized. The method was successfully applied to the determination of acetylsalicylic acid in pharmaceutical preparations. The recovery results obtained by the method were satisfactory. Copyright © 2013 John Wiley & Sons, Ltd.     

Flow‐injection chemiluminescence of the luminol–potassium periodate system enhanced by TGA–capped CdTe quantum dots for the determination of theophylline

The chemiluminescence (CL) behaviour of the luminol–potassium periodate system enhanced by CdTe quantum dots capped with thioglycolic acid (TGA–CdTe QDs) was studied using kinetic experiments, CL spectra, UV–vis absorption spectra and fluorescence spectra. The production of oxygen‐containing reactant intermediates (O₂^?? and OH^?) in the present CL system was verified by CL. The possible CL mechanism was discussed in detail. Furthermore, theophylline (THP) was determined based on its enhancement of the CL intensity of the CdTe QDs–luminol–potassium periodate system coupled with a flow‐injection technique. Under these optimized conditions, the linear range was found to be from 1.0 × 10^?8 to 1.0 × 10^?5 g/mL with a detection limit of 2.8 × 10^?9 g/mL (3σ). The recoveries for the determination of THP in tablets were from 98.2 to 99.6%.     

Flow‐injection chemiluminescence method for the determination of chloramphenicol based on luminol–sodium periodate order‐transform second‐chemiluminescence reaction

A new chemiluminescence (CL) reaction was observed when chloramphenicol solution was injected into the mixture after the end of the reaction of alkaline luminol and sodium periodate or sodium periodate was injected into the reaction mixture of chloramphenicol and alkaline luminol. This reaction is described as an order‐transform second‐chemiluminescence (OTSCL) reaction. The OTSCL method combined with a flow‐injection technique was applied to the determination of chloramphenicol. The optimum conditions for the order‐transform second‐chemiluminescence emission were investigated. A mechanism for OTSCL has been proposed on the basis of the chemiluminescence kinetic characteristics, the UV‐visible spectra and the chemiluminescent spectra. Under optimal experimental conditions, the CL response is proportional to the concentration of chloramphenicol over the range 5.0 × 10^?7–5.0 × 10^?5 mol/L with a correlation coefficient of 0.9969 and a detection limit of 6.0 × 10^?8 mol/L (3σ). The relative standard deviation (RSD) for 11 repeated determinations of 5.0 × 10^?6 mol/L chloramphenicol is 1.7%. The method has been applied to the determination of chloramphenicol in pharmaceutical samples with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.     

Investigation on the interaction between dihydroxybenzene and Fe3+- H2O2-Rh6G system based on enhancing chemiluminescence.

A highly sensitive flow-injection chemiluminescence (FI-CL) method has been developed for the determination of dihydroxybenzene, based on the hydroxyl radical reaction. Hydroxyl radical (.OH) produced by the reaction of Fe(3+) and H(2)O(2) oxidize rhodamine 6G to produce weak CL. It was observed that catechol and hydroquinone greatly enhanced the weak CL reaction. However, the proposed CL system is not suitable for determination of resorcinol because the enhancement reaction is very slow. The proposed procedure has a linear range of 0.01-2 mg/L for catechol, with a detection limit of 0.006 mg/L, and 0.008-1 mg/L for hydroquinone, with a detection limit of 0.004 mg/L. The possible mechanism of the CL system is discussed.     

Sensitive determination of synephrine by flow-injection chemiluminescence.

It was found that light emission produced by the oxidation of luminol by potassium ferricyanide in basic medium was enhanced by synephrine, an anti-obesity drug. The optimum conditions for this chemiluminescent reaction were studied in detail in a flow injection system and employed in a new, simple and rapid method for the determination of synephrine. A mechanism for this reaction is proposed, based on the chemiluminescence reaction spectra. In the optimum conditions, CL intensity is proportional to concentration of synephrine in the 0.008-1 microg/mL range. The limit of detection is 1.6 ng/mL for synephrine (3sigma), and the relative standard deviation (n = 11) is 2.6% for 0.5 microg/mL synephrine. The method was applied to the determination of synephrine in herbal products, citrus fruit and biological fluids. The recoveries were satisfactory (90-102%). The results given by the proposed method are in good agreement with those given by HPLC-UV.     

Direct chemiluminescence determination of ibuprofen by the enhancement of the KMnO(4)-sulphite reaction.

A simple, rapid, flow-injection chemiluminescence (CL) method is described for the determination of ibuprofen. A strong CL signal was detected when a mixture of the analyte and sulphite was injected into acidic KMnO(4). The CL signal is proportional to the concentration of ibuprofen in the range 0.1-10.0 mg/L. The detection limit is 0.02 mg/L ibuprofen, the relative standard deviation is 1.8% (0.5 mg/L ibuprofen; n = 11) and the sample measurement frequency is 120/h. The proposed method was successfully applied to the determination of ibuprofen in pharmaceutical preparations and in spiked urine samples. The mechanism of the CL reaction is also discussed.     

Flow injection chemiluminescence determination of dihydralazine sulphate based on permanganate oxidation sensitized by rhodamine B.

A novel flow injection chemiluminescence (CL) method for the determination of dihydralazine sulphate (DHZS) is described. The method is based on the CL produced during the oxidation of DHZS by acidic permanganate solution in the presence of rhodamine B. Rhodamine B is suggested as a fluorescing compound for the energy-transferred excitation. The CL emission allows quantitation of DHZS concentration in the range 5-800 ng/mL, with a detection limit of 1.9 ng/mL (3sigma). The experimental conditions for the CL reaction are optimized and the possible reaction mechanism is discussed. The method has been applied to the determination of DHZS in pharmaceutical preparations and compares well with the high performance liquid chromatography (HPLC) method.     

Inhibition of the system luminol-H2O2-Fe(CN)63− chemiluminescence by the Mn(II) indirect determination of isoniazid in a pharmaceutical formulation

A flow injection procedure for the indirect chemiluminescent determination of isoniazid is proposed. The method is performed in a flow-injection manifold provided with a solid-phase reactor. The reactor was made from manganese dioxide physically entrapped by polymerization; the redox reaction isoniazid–manganese dioxide released Mn(II) which was monitored through its inhibitory effect on the reaction between luminol and hydrogen peroxide in presence of potassium hexacyanoferrate(III). The procedure resulted in a linear calibration graph over the range 5–15 mg/L of isoniazid with a sample throughput of 43 samples/h. The influence of foreign compounds was studied and the method was applied to determination of the drug in a pharmaceutical formulation. © 1998 John Wiley & Sons, Ltd.     

Ultrasensitive assay of clindamycin in medicine and bio-fluids with chemiluminescence detection.

A simple chemiluminescence (CL) method using flow injection has been developed for the determination of clindamycin, based on the inhibitory effect of clindamycin on the CL generated from the luminol-K(3)Fe(CN)(6) system in alkaline medium. It was found that the decrement of CL intensity was linear with the logarithm of clindamycin concentration over the range 0.7-1000 ng/mL. The detection limit was 0.2 ng/mL with a relative standard deviation (RSD) of <5.0% (n = 7). At a flow rate of 3.0 mL/min, a complete analytical process could be performed within 0.5 min, including sampling and washing. The proposed procedure was applied successfully to the determination of clindamycin in pharmaceutical preparations and human urine without pretreatment.     

Highly selective determination of phenolphthalein by flow injection chemiluminescence method based on a molecular imprinting polymer

The phenolphthalein‐imprinted polymer was prepared with methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross‐linker. Taking advantage of the quenching effect of phenolphthalein on the potassium permanganate–HCl–anhydrous alcohol chemiluminescence system, a new model was established to determine phenolphthalein by a highly selective flow injection chemiluminescence method. The traditional flow‐though cell was replaced with a novel flow path using a Y‐shaped polymethyl methacrylate column, through which the three reactants were injected simultaneously. The linear range of this assay was from 1.0 × 10^?8 to 1.0 × 10^?6 g/mL (r = 0.9978). The limit of detection was 8.9 × 10^?9 g/mL. The relative standard deviation for the determination of 1.0 × 10^?8 g/mL phenolphthalein solution was below 2.9% (n = 11). The proposed method was applied to the determination of phenolphthalein in real samples with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.     

A novel chemiluminescence system for the determination of daidzein and its hydroxyl radical-scavenging capacity

A novel chemiluminescence (CL) system was established for the determinations of daidzein in pharmaceutical preparations and to assess its ability to scavenge hydroxyl radicals. It was shown that a strong CL signal generated when eosin Y was mixed with Fenton reagent was decreased significantly when daidzein was added to the reaction system due to partial scavenging of the hydroxyl radicals in the solution. The extent of decrease in the CL intensity had a good stoichiometric relationship with the daidzein concentration. Based on this, we developed a new method for the determination of daidzein, using a flow‐injection chemiluminescence (FI–CL) technique. Under the optimal conditions, the linear range of daidzein concentration was 8.0 × 10^–8–3.0 × 10^–6 mol/L (R = 0.9982), with a detection limit of 9.0 × 10^–9 mol/L (S:N = 3), and the RSD was 5.8% for 1.0 × 10^–6 mol/L daidzein (n = 11). This method was successfully used in the determination of daidzein in tablets and for evaluation of the hydroxyl radical‐scavenging capacity of daidzein. The possible reaction mechanism of the CL system is discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Enhancement of chemiluminescence of the KIO4–luminol system by gallic acid,acetaldehyde and Mn2+: application for the determination of catecholamines

Chemiluminescence (CL) from the oxidation of luminol with potassium periodate in strong alkaline solutions was greatly enhanced by the combined effect of gallic acid, acetaldehyde and Mn²⁺. The CL spectra exhibited only one emission band at 425 nm, indicating 3‐aminophthalate as the emitting species. Various scavengers for superoxide anion, hydroxyl radical and singlet oxygen quenched the CL emission very efficiently (74–100%), suggesting the possible involvement of these reactive oxygen species (ROS) in the CL reactions. It is postulated that oxidation of gallic acid and acetaldehyde by periodate catalyzed by Mn²⁺ generates these ROS, which then react with luminol to enhance the CL emission. We also found that the enhanced CL emission was strongly inhibited by catecholamines, probably because of their effective scavenging of ROS. Based on this observation, a simple, rapid and sensitive new CL method was developed for the determination of catecholamines. The detection limits (3σ) for dopamine, l‐ dopa, norepinephrine and epinephrine were 0.63, 1.37, 0.56 and 14.3 nmol/L, respectively. The linear range was 1–10 nmol/L; relative standard deviations were 0.71–1.34% for 0.1 µmol/mL catecholamines. This CL method was applied to the determination of catecholamines in pharmaceutical injections with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.     

Flow injection–chemiluminescence determination of acyclovir

The chemiluminescence (CL) reaction of acyclovir (ACV)–potassium permanganate, with formaldehyde as an enhancer, was investigated by the flow‐injection system, and a new method is reported for the determination of ACV on the basis of the reaction. The method is rapid, effective and simple for the determination of acyclovir in the range 0.2–80 mg/L, with a limit of detection of 0.06 mg/L (3 S:N), a relative standard deviation (RSD) of 3.7% for the determination of 1.0 mg/L acyclovir solution in 11 repeated measurements. The method has been applied to the determination of acyclovir in pharmaceuticals, with satisfactory results. The possible reaction mechanism is also discussed briefly. Copyright © 2011 John Wiley & Sons, Ltd.     

Flow injection–chemiluminescence determination of amoxycillin using potassium permanganate and formaldehyde system

It was found that amoxycillin can react with potassium permanganate in an acidic medium to produce chemiluminescence, which is greatly enhanced by formaldehyde. The optimum conditions for this chemiluminescent reaction were studied in detail using a flow‐injection system. The experimental results indicate that, under optimum conditions, the chemiluminescence intensity is linearly related to the concentration of amoxycillin in the range 5.48 × 10^?8–2.74 × 10^?6 mol[sol ]L, with a detection limit (3σ) of 4.1 × 10^?8 mol[sol ]L. The relative standard deviation was 1.0% at 1.1 × 10^?6 mol[sol ]L amoxycillin (n = 11 measurements). This method has the advantages of high sensitivity, fast response and ease of operation. The method was successfully applied to the determination of amoxycillin in raw medicines and capsules. Copyright © 2005 John Wiley & Sons, Ltd.