Determination of indomethacin in urine using molecule imprinting-chemiluminescence method

Applications of molecularly imprinted polymers for solid-phase extraction of non-steroidal anti-inflammatory drugs and analgesics from environmental waters and biological samples

The occurrence of pharmaceuticals used as non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics in the aquatic environment is a threat to humans and aquatic species at large. The primary route of these pharmaceuticals to aquatic environment is through human waste such as urine and faeces. The application of molecularly imprinted polymers (MIPs) in the solid-phase extraction (SPE) of such pollutants from environmental and biological samples is important for the pre-concentration of compounds and selectivity of the analytical methods. To date, there are still limited commercial suppliers of MIPs. However, it is easy to synthesize such polymers via non-covalent imprinting approach using easily available and affordable reagents. Therefore, the applications of MIPs in the SPE of NSAIDs and analgesics from environmental and biological samples are reviewed. This is very important because despite the fact that review articles on applications of MIPs for organic compounds have been reported, very little has focussed on NSAIDs and analgesics which are the major studied pharmaceuticals in the environment and biological samples. The review also brings out important aspects of common reagents used including the template molecules during MIP synthesis. Application and future trends are also discussed. Gaps such as little use of environmental friendly reagents such as ionic liquids have been identified. Also, the lack of MIP applications to some compounds such as fenoprofen has been observed which is likely to be developed in the near future.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Ethanol as an alternative to formaldehyde for the enhancement of manganese(IV) chemiluminescence detection

Previous applications of manganese(IV) as a chemiluminescence reagent have required the use of formaldehyde to enhance the emission intensity to analytically useful levels. However, this known human carcinogen (by inhalation) is not ideal for routine application. A wide range of alternative enhancers have been examined but to date none have been found to provide the dramatic increase in chemiluminescence intensities obtained using formaldehyde. Herein, we demonstrate that ethanol offers a simple, safe and inexpensive alternative to the use of formaldehyde for manganese(IV) chemiluminescence detection, without compromising signal intensity or sensitivity. For example, chemiluminescence signals for opiate alkaloids using 50-100% ethanol were 0.8-1.6-fold those using 2M formaldehyde. This innocuous alternative enhancer is shown to be a particularly effective for the direct detection of thiols and disulfides by manganese(IV) chemiluminescence, which we have applied to a simple HPLC procedure to determine a series of biomarkers of oxidative stress.

A review of recent advances in chemiluminescence detection using nano-colloidal manganese(IV)

The application of 'soluble' (colloidal) manganese(IV) for chemiluminescence detection is reviewed, focussing on papers published since the last comprehensive review of the subject in 2008. Advances in this reagent system include: the on-line formation of manganese(IV); new insight into the light-producing pathway and selectivity of the reagent; its application to assess total antioxidants in plant derived samples and oxidative stress in biological fluids and tissues; and the replacement of the formaldehyde enhancer with ethanol.

Synthesis and Application of Molecularly Imprinted Sol-Gel Film for Simultaneous Determination of Multi-Component Pesticide Residue

In this paper, three kinds of molecularly imprinted sol-gel film (MISF) which have good thermal and chemical stability and three-dimensional network porous structure have been developed. The material was synthesized by sol-gel technology using lambda-cyhalothrin, trichlorphon and beta-cyfluthrin as model analytes. The special structural behavior makes the material have good capability to seizure and capture template molecules which enhanced the MISF’s recognition efficiency and the property of separation and enrichment. The material was environmental friendly and easy to operate. The binding characteristic of the imprinted film to the three pesticides was evaluated by equilibrium binding experiments. The SEM of the three MISF has been performed to characterize the morphology of MISF. The MISFs were combined with chemiluminescence (CL) technology by modifying the sol-gel into 96 micro-well plate to establish one molecular imprinting- chemiluminescence (MI-CL) sensor which realized high selectivity, sensitivity and high throughput simultaneous assay of three pesticides. The proposed method was successfully applied to the simultaneous determination of multi-component pesticide residue in foodstuff.

Immuno-like assays and biomimetic microchips

Biomimetic assays with molecularly imprinted polymers (MIPs) are bound to be an alternative to the traditional immuno-analytical methods based on antibodies. This is due to the unique combination of advantages displayed by the artificial materials including the absence of animal inoculation and sacrifice, unnecessary hapten conjugation to a carrier protein for stimulated production, the possibility of manufacturing MIPs against toxic substances, excellent physicochemical stability, reusability, ease of storage, and recognition in organic media. If the selectivity and affinity of MIPs are increased, many more immuno-like assays will be developed using radioactive, enzymatic, colorimetric, fluorescent, chemiluminescent, or electrochemical interrogation methods. This chapter provides a comprehensive comparison between the bio- and biomimetic entities and their usage.

Sequential injection analysis (SIA)-chemiluminescence determination of indomethacin using tris[(2,2′-bipyridyl)]ruthenium(III) as reagent and its application to semisolid pharmaceutical dosage forms

Automated sequential injection (SIA) method for chemiluminescence (CL) determination of nonsteroidal anti-inflammatory drug indomethacin (I) was devised. The CL radiation was emitted in the reaction of I (dissolved in aqueous 50% v/v ethanol) with intermediate reagent tris(2,2'-bipyridyl)ruthenium(III) (Ru(bipy)(3)(3+)) in the presence of acetate. The Ru(bipy)(3)(3+) was generated on-line in the SIA system by the oxidation of 0.5mM tris(2,2'-bipyridyl)ruthenium(II) (Ru(bipy)(3)(2+)) with Ce(IV) ammonium sulphate in diluted sulphuric acid. The optimum sequence, concentrations, and aspirated volumes of reactant zones were: 15 mM Ce(IV) in 50mM sulphuric acid 41 microL, 0.5 mM Ru(bipy)(3)(2+) 30 microL, 0.4M Na acetate 16 microL and I sample 15 microL; the flow rates were 60 microLs(-1) for the aspiration into the holding coil and 100 microLs(-1) for detection. Calibration curve relating the intensity of CL (peak height of the transient CL signal) to concentration of I was curvilinear (second order polynomial) for 0.1-50 microM I (r=0.9997; n=9) with rectilinear section in the range 0.1-10 microM I (r=0.9995; n=5). The limit of detection (3sigma) was 0.05 microM I. Repeatability of peak heights (R.S.D., n=10) ranged between 2.4% (0.5 microM I) and 2.0% (7 microM I). Sample throughput was 180 h(-1). The method was applied to determination of 1 to 5% of I in semisolid dosage forms (gels and ointments). The results compared well with those of UV spectrophotometric method.

Detection of indomethacin by high-performance liquid chromatography with in situ electrogenerated Mn(III) chemiluminescence detection

The determination of indomethacin (INM) in pharmaceutical and biological samples by means of high-performance liquid chromatography (HPLC) with in situ electrogenerated Mn(III) chemiluminescence (CL) detection was proposed. The method was based on the direct CL reaction of INM and Mn(III), which was in situ electrogenerated by constant current electrolysis. The chromatographic separation was carried out on Nucleosil RP-C(18) column (250 mm x 4.6 mm; i.d., 5 microm; pore size, 100 A) at 20 degrees C. The mobile phase consisted of methanol:water:acetic acid=67:33:0.1 solution. At a flow rate of 1.0 mL min(-1), the total run time was 10 min. The effects of several parameters on the HPLC resolution and CL emission were studied systematically. Under the optimal conditions, a linear range from 0.01 to 10 microg mL(-1)(R(2)=0.9991), and a detection limit of 8 ng mL(-1) (signal-to-noise ratio=3) for INM were achieved. The relative standard deviations (R.S.D.) for 0.1 microg mL(-1) INM were 2.2% within a day (n=11) and 3.0% on 5 consecutive days (n=6), respectively. The recovery of INM from urine samples was more than 92%. The applicability of the method for the analysis of pharmaceutical and biological samples was examined.