Development of a spectrophotometric analytical approach for the measurement of cefdinir in various pharmaceuticals.

An accurate and sensitive determination procedure has been established for the quantification of cefdinir in pure and pharmacological formulas. The approach was dependent on derivatizing cefdinir with sodium anthraquinone-2-sulfonate (SAS) in an alkaline medium to produce a magenta-colored derivative with a maximum absorbance at 517 nm against the reagent blank. Different factors affecting the interaction of cefdinir with SAS were studied carefully and optimized, such as the buffer value, medium acidity, the duration of hydrolysis, and the reagent percentage. Under optimized conditions, a linear calibration curve with a correlation coefficient of R2 = 0.9995 was obtained over the concentration range of cefdinir 0.5-100 µg/mL. The values of the parameters that represented the sensitivity of the method were satisfactory, i.e., the limit of detection, the limit of quantification, as well as Sandell's sensitivity (л) were 0.1 µg/mL, 0.5 µg/mL, and 0.064 µg/cm2/0.001 Au, respectively. The relative standard deviation was below 1.35%, while the percentage recovery was 99.930%-102.257%. The mole ratio of the colored complex was estimated by following Job's method of continuous variation, which indicated that the cefdinir-SAS ratio was 1:1. The suggested approach was proven to be adequately accurate, precise, and without interfering with common excipients and additives. Thus, it could be implemented successfully for the standard determination of cefdinir in its pure and pharmaceutical forms.

Direct acetylation and determination of chlorophenols in aqueous samples by gas chromatography coupled with an electron-capture detector.

A method was developed that offers a rapid, simple and accurate technique for the determination of chlorophenols at trace levels in aqueous samples with very limited volumes of organic solvents. These compounds were acetylated, then preliminarily extracted with n-hexane. The enriched chlorophenols were directly analyzed using gas chromatography with an electron-capture detector. The detection limits were in the range of 0.001-0.005 mg/L, except for 2-chlorophenol, which was always above 0.013 mg/L. Relative standard deviation for the spiked water samples ranged from 2.2 to 6.1%, while relative recoveries were in the range of 67.1 to 101.3%.

Chlorophenols in Tigris River and drinking water of Baghdad, Iraq.

A study was conducted on a stretch of Tigris river crossing Baghdad city to determine the concentration of some chlorophenols pollutants. Aqueous samples were preliminary enriched about 500 times and the chlorophenols have determined using high performance liquid chromatography HPLC. Limits of detection LOD were (0.007-0.012 mg L(-1)), relative standard deviations RSD% were 2.4%-5.59% and relative recoveries were 51.06%-104.07%. The existence of chlorophenols in Tigris river was in the range 0.023-4.596 mg L(-1). The developed method suggested in this study can be applied for routine analysis and monitoring of chlorinated phenols in environmental aqueous samples.