A spectrophotometric and first derivative spectrophotometric method was developed in aquatic Tween 80 micellar solutions for selective determination of nickel without using any pre-separation step. 1-(2-Pyridylazo)2-naphthol (PAN), as a sensitive chromogenic complexing agent formed a red-colored Ni(II)-PAN complex in Tween 80 media with satisfactory solubility and stability. Conditions such as ...

A simple spectrophotometric system, based on a prolonged pseudo-liquid drop device as an optical cell and a handheld charge coupled device (CCD) as a detector, was constructed for automatic liquid-liquid extraction and spectrophotometric speciation of trace Cr(VI) and Cr(III) in water samples. A tungsten halogen lamp was used as the light source, and a laboratory-constructed T-tube with two ope...

A simple, rapid, and environmentally-friendly spectrophotometric method for nitrite detection was developed. Detection based on a redox reaction with iodide ions in an acidic condition. The evaluated by detecting the increase absorbance of colored product iodine at 362 nm wavelength. To obtain good performance, concentration, hydrochloric acid time were optimized. In optimal condition, develope...

This study examined the role of self-monitoring support for writing skill improvement in a reciprocal peer review of writing system called SWoRD (Cho & Schunn, 2007). Because self-monitoring has been identified as a critical component in self-regulated learning (Butler & Winne, 1995; Cresswell, 2000; Zimmerman & Risemberg, 1997), students were provided with opportunities to self-monitor their w...

In this precise, accurate, and specific liquid-chromatographic procedure for determining progesterone in serum, the serum is diluted 10-fold with water/methanol (65/35 by vol), and the progesterone is extracted from the sample by passage through a column of graphitized carbon black (Carbopack B, Supelco). After washing the column, we elute the progesterone with chloroform/methanol (90/10 by vol...