Determination of phenol, m-, o- and p-cresol, p-aminophenol and p-nitrophenol in urine by high-performance liquid chromatography.
ABSTRACT A method for the biological monitoring of human exposure to aromatic hydrocarbons, nitrocompounds, amines and phenols has been developed. Phenol, cresols, p-aminophenol, p-nitrophenol and their glucorono- or sulpho-conjugates, were quantified by HPLC; 4-chlorphenol was added as internal standard. After enzymatic hydrolysis, the free compounds were extracted with an organic solvent and analyzed by an isocratic HPLC Perkin Elmer system at ambient temperature and at a flow-rate of 1 ml/min. The column was a reversed-phase Pecosphere 3 x 3 C18 Perkin Elmer; the mobile phase was a 30:70:0.1 (v/v/v) methanol-water-orthophosphoric acid mixture and the chromatogram was monitored at 215 nm. Identification was based on retention time and quantification was performed by automatic peak height determination, corrected for the internal standard. The recovery was ca. 95% for phenol and cresols; 90% for p-nitrophenol; 85% for p-aminophenol; the coefficients of variance were less than 6% within analysis (n = 20) and less than 10% between analysis (n = 20). The detection limits, at a signal/noise ratio of 2, were 0.5 mg/l for phenol and cresols and 1 mg/l for p-aminophenol and p-nitrophenol.
- Journal of High Resolution Chromatography 12/1993; 16(12):736-737.
- [Show abstract] [Hide abstract]
ABSTRACT: We have prepared low-dimensional silver oxide nanoparticles (NPs) by a sono-chemical methodusing reducing agents in alkaline medium. The resulting NPs were characterized by UV/vis and FT-IRspectroscopy, X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray energydispersive spectrometry (XEDS), and field-emission scanning electron microscopy (FESEM). They weredeposited on a flat-polycrystalline gold electrode (AuE, surface area, 0.0216 cm2) to give a sensor witha fast response toward 4-nitrophenol (4-NPh) in liquid phase. The sensor also displays good sensitiv-ity and long-term stability, and enhanced electrochemical performances. The calibration plot is linear(r2= 0.9873) over the large concentration range (LDR, 1.0 �M to 0.5 mM). The sensitivity and detectionlimit is calculated to ∼4.740 �A cm−2mM−1and ∼0.19 �M (signal-to-noise ratio, at a SNR of 3), respec-tively. We also discuss possible future prospective uses of this metal oxide nanomaterials in terms ofchemical sensing.Electrochimica Acta 12/2013; 112:422– 430. · 4.09 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: A flow piezoquartz immunosensor was developed for the rapid estimation of 4-aminophenol in pharmaceutical formulations based on paracetamol. The bioreceptor coating was a 4-aminophenol-protein conjugate (4-AP-GA-BSA), immobilized on the silanized surface of a silver electrode. The effects of the concentration of polyclonal antibodies on the analytical signal of the sensor were studied: the activities of immunological reagents were assessed in terms of the binding constant K b. A method for flow-injection estimation of 4-aminophenol in pharmaceutical formulations using the piezoquartz immunosensor as the detector was developed. The calibration curve was linear over the concentration range 2–120 ng/ml and the detection limit for 4-aminophenol was 1.1 ng/ml.Pharmaceutical Chemistry Journal 01/2008; 42(4):220-223. · 0.32 Impact Factor