Trace Water In Organic Solvents Research Articles

Bonding-induced emission of silyl-protected copper nanoclusters for luminescence turn-on detection of trace water in organic solvents.

A novel bonding-induced emission (BIE) phenomenon of silyl-protected copper nanoclusters was observed and identified, and a new detection method for trace water in organic solvents was established based on a water-triggered BIE process. This assay employs simple and commercially available reagents and is capable of determining trace water at the ppm level.

The electrochemiluminescence of an iridium complex induced by hydroxide and ethoxide ions in organic solvents

The electrochemical and the electrochemiluminescence (ECL) reaction between an iridium complex (phenylquinoline)2Ir(acetylacetone) [(pq)2Ir(acac)] and water were studied in organic solvents. In the presence of a base, hydroxide ions, formed from the dissociation of trace water, can act as coreactants to induce strong luminescence upon application of an appropriate voltage. The mechanism study revealed that the electrochemically produced hydroxyl radicals were the key components for the ECL reaction. As the light emission intensity was proportional to the water contents, hence the method can be used for the determination of trace water in organic solvents. The linear response ranges were 0.001–0.05%, 0.003–1.00%, 0.01–1.00%, 0.01–1.00%(v/v), respectively in dichloromethane, acetonitrile, acetone and N,N′-dimethylformamide (DMF). The limit of detections as low as ppm levels were readily achievable in these solvents. When ECL experiment was carried out in ethanol, the ECL emission was observed even without the presence of water. Further experiments proved that ethoxide ion can also act as a coreactant and the ECL intensity was linearly correlated with the sodium ethoxide concentration in the range from 0.01 to 10μM, suggesting that the ECL approach is able to quantify the sodium ethoxide content in ethanol.

A microgap impedance sensor for the determination of trace water in organic solvents

A microgap impedance sensor with a 50 μm gap was developed for the determination of trace water in organic solvents by coating poly(dimethyldiallylammonium chloride) (PDMDAAC) and ferricyanide/ferrocyanide composite materials on indium tin oxide (ITO). The electrochemical properties of the composite materials were investigated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We observed that the impedance response of the sensor depended on the concentration of trace water in the organic solvents. Under optimized conditions, the linear range for the determination of trace water was 0-0.06% for chloroform (CHCl(3)), 0-0.10% for acetone (CH(3)COCH(3)), 0-0.12% for tetrahydrofuran (THF), and 0-0.10% for acetonitrile (CH(3)CN), and the detection limits were 0.65, 1.54, 0.61, and 1.72 ppm, respectively. The results obtained from the impedance sensors were comparable to those obtained using the traditional Karl Fischer method.

Spectrophotometric determination of trace water in organic solvents with a near infrared absorbing dye

A spectrophotometric method for the determination of trace water in organic solvents using a near infrared absorbing dye has been developed. This method is based on the effect that a minor change in polarity of the solvent caused by trace water content determines the extent of aggregation of a near-infrared dye monomer. This change can be detected spectrophotometrically. The calibration curves for methanol, ethanol, and isopropanol were determined. This method has the highest sensitivity (em = 16.73 unit) for water in isopropanol and the lowest sensitivity (em = 2.806 unit) for water in methanol. The correlation coefficient ( R) 2 values for the regression lines ranges from 0.990–0.998. The linear range of the method for ethanol is 0.001–0.5%, for isopropanol is 0.001–0.1%, and for methanol is 0.001–1.0%. The limit of detection for ethanol, isopropanol, and methanol are 0.0001, 0.0001, and 0.005% water, respectively. The developed method is sensitive, simple and easy to operate, and the cost of analysis is low.

Determination of trace water in organic solvents by a spectrofluorimetric method

A new method for the spectrofluorimetric determination of water in organic solvents has been developed. It is based on formation of the exciplex of pyridoxal with water. The procedure is sensitive, reproducible and useful for the determination of trace water in cyclohexane, petroleum ether, benzene, carbon tetrachloride, diethyl ether, tetrahydrofuran, dioxan, etc. The solubility of water in benzene at various temperatures has been determined.