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A new and rapid potentiometric method for determination of flucloxacillin is developed. The method involves development of a flucloxacillin sensor with a membrane consisting of Aliquat 336S-flucloxacillin as an electroactive material in poly vinyl chloride matrix membrane plasticized with orthonitrophenyl-octylether or dioctylphthalate. The sensor shows fast, stable and reproducible response over the concentration range of 1.0 × 10 −5 –1.0 × 10 −2 M flucloxacillin with anionic slopes of 60.7 ± 0.3 and 61.2 ± 0.2 and pH ranges of 6–11 and 7–11 for o -nitrophenyloctylether ( o -NPOE) and dioctylphthalate (DOP) plasticized based membrane sensors, respectively. The response time of the sensor is stable and fast (7 s). The sensor exhibits high selectivity towards flucloxacillin in presence of amoxicillin, ampicillin, dicluxacillin, pencillin, many anions and drug excipients and diluents. Validation of the method according to the quality assurance standards shows suitability of the proposed sensors for use in the quality control assessment of the drug. Results with average recoveries of 99.6% and 99.7% and mean standard deviations of ±1.2% and ±1.5% for o -NPOE and DOP plasticized based membrane sensors, respectively, of the nominal are obtained which compare fairly well with data obtained using the British Pharmacopoeia method.

Three simple, sensitive, and highly accurate spectrophotometric methods have been developed for the determination of oxomemazine hydrochloride (OXO‐HCl) in bulk and in pharmaceutical formulations. These methods are based on the formation of yellow ion‐pair complexes between the examined drug and bromocresol green (BCG), congo red (CR), and methyl orange (MO) as reagents in universal buffer solution of pH 3.0, 5.5, and 3.5, respectively. The formed complexes were extracted with chloroform and measured at 413, 495, and 484 nm, respectively for the three systems. The best conditions of the reaction were studied and optimized. Beer's law was obeyed in the concentration ranges 2.0–18.0, 2.0–14.0, and 2.0–16.0 µg ml−1 with molar absorptivity of 4.1×104, 1.1×104, and 3.5×104 mol−1cm−1, for the BCG, CR, and MO methods, respectively. Sandell's sensitivity, correlation coefficient, detection, and quantification limits are also calculated. The proposed methods have been applied successfully for the analysis...

A method based on on‐line solid phased extraction capillary liquid chromatography‐electrospray ionization‐mass spectrometry (SPE‐capLC‐ESI‐MS) has been developed for the determination of oxomemazine in human plasma. Prior to injection, 0.5 mL of plasma spiked with metronidazole (internal standard) was mixed with ammonium formate buffer and methyl orange, which served as an ion pair reagent for effective chloroform liquid–liquid extraction. The employment of methyl orange as an ion pair reagent doubled the extraction efficiency, as compared to not using methyl orange. In preliminary experiments, conventional LC‐UV instrumentation was employed. However, it was found that employing a capillary column with an inner diameter of 0.3 mm increased the sensitivity by a factor of ∼100, when injecting the same mass of analyte. Incorporating an easily automated reversed phase column switching system with SPE made it possible to inject up to 100 µL of solution, and the total analysis time was 5 minutes. The m...

An investigation of lakebed sediment found elevated polycyclic aromatic hydrocarbon (PAH) levels, and a nearby former manufactured gas plant (MGP) site was identified as the most likely source. Forensic chemistry or “chemical fingerprinting” was conducted on sediment samples from a boat slip in the vicinity of the MGP and on-shore soil samples from the MGP property in order to determine whether or not the former MGP was the origin of the PAHs found in the sediment. An analysis of the data from gas chromatography with flame ionization detection (GC/FID) and mass spectrometry (GC/MS) suggested that the PAH distributions measured in the sediment samples were similar to those measured in samples of tarry soil from the former MGP site. However, because of the urban and industrial land use surrounding the former MGP site, it was also possible that there was a PAH contribution to the sediments from urban runoff or other industrial and municipal discharges. The compound-specific isotope ratios (CSIRs) of carbon i...