Water detecting

A Btu meter may be used in the fuel-quality system as an aid in determining turbine system efficiency. A water capacitance probe is used for detection of water in the fuel line. A water-detecting device can be incorporated into the corrosion monitoring system. This monitoring device is based on detection of changes in the dielectric constant of unknown fluid components... 

Apte and Gunn [23] used liquid-liquid extraction, involving 1 1 1 trichlor-ethane extraction of the ammonium pyrrolidine dithiocarbamates to concentrate copper, nickel, lead, and cadmium from estuary water. (Detection limits... 

Armani, A. M. Vahala, K. J., Heavy water detection using ultra high Q microcavities, Opt. Lett. 2006, 31, 1896 1898... 

Calculations From the chromatograms obtained and taking into account any water detectable in solution (1), calculate the percentage of water taking 0.9972 g as its weight per ml at 20 °C. 

FIGURE 10 Chromatograms showing the effect of sample solvent and injection volume on peak shape.The peak at 5 min is an impurity in a NCE. Column Supelco Discovery RP amide C16 mobile phase, 2.5% acetonitile in water detection, UV 190 nm injection 10, 20,30,50 and 100 pL sample solvent (A) 2.5% (B) 10% (acetonitrile in water). 

No information concerning the release of 1,2-diphenylhydrazine to water was located in the literature. If discharged to water, detectable concentrations will probably persist for only a short time, since the half-life of (100 pg/L) 1,2-diphenylhydrazine in wastewater is about 15 minutes (Riggin and Howard 1979, 1982)... 

Elemental composition Cu 64.18%, Cl 35.82%. Copper(I) chloride is dissolved in nitric acid, diluted appropriately and analyzed for copper by AA or ICP techniques or determined nondestructively by X-ray techniques (see Copper). For chloride analysis, a small amount of powdered material is dissolved in water and the aqueous solution titrated against a standard solution of silver nitrate using potassium chromate indicator. Alternatively, chloride ion in aqueous solution may be analyzed by ion chromatography or chloride ion-selective electrode. Although the compound is only sparingly soluble in water, detection limits in these analyses are in low ppm levels, and, therefore, dissolving 100 mg in a liter of water should be adequate to carry out aU analyses. 

Lissemore, L.A.Pharmaceuticals in Agricultural Surface Waters Detection, Distribution, Exposure and Risk, PhD thesis, University of Guelph. (2005). 

The formation of water, detected by the copper sulfate test, may be consistent with the above scheme. The decreasing yield of cyclohexene oxide with decreasing oxygen concentration suggests that cyclohexene oxide could be formed from the direct reaction of cyclohexene with... 

When transfer is complete, rinse membrane three times for 5 min each with high-pu-rity water detect proteins on the membrane using an aqueous stain such as Ponceau S (UN/TB3.3) if desired. 

Barbiturates Barbital, phenobarbital Separated on a C-18 high carbon loaded silica column mobile phase methanol-water detected by UV at 254 nm... 

Atrazine has been detected in surface water and groundwater in several of the major-use states (Keck, 1991 Thurman et al, 1991 Goolsby et al, 1991a, b Hall et al, 1999 USGS, 2006). Typically, groundwater detections of atrazine occur much less frequently than surface water detections. Also, groundwater detections are usually lower in concentration than those in surface water. In surface water, atrazine concentrations in streams and rivers are episodic,... 

A direct injection nebuliser (DIN) was used to interface LC with ICP-MS (Shum et al., 1992a). The DIN transferred all of the sample into the inductively coupled plasma. Microscale LC separations in small packed columns were studied because the column flow rates of about 30 ml min 1 were compatible with the DIN. The low dead volume (less than 1 ml) of the interface prevented excessive band broadening. Eluents containing up to 85% methanol were accommodated. The analyte signal varied by about 20% as the eluent changed from 20% to 80% methanol in water. Detection limits for arsenic and tin species using the HPLC-DIN-ICP-MS system were 0.2-0.6 and 8-10pg, respectively. 

R 17] [A 5] A number of sensors for oxygen and water detection and also for the measurement of acidity and conductivity are already available, as shown in Figure 4.70. 

High performance liquid chromatography in reversed phase mode was performed isocratically with 82% acetonitrile in water. Detection wavelengths of 254 and 280nm... 

Shen et al. [262] evaluated indirectly coupled plasma mass spectrometry as an element detector for the supercritical fluid chromatography of organotin compounds in water. Detection limits of 0.04 and 0.047pg absolute were obtained, respectively, for tetrabutyltin and tetraphenyltin. 

Anion Electrophoretic method Comments Non saline waters Detection LD Ref. 

Greaves and Unger [218] have used chemical ionisation mass spectrometry with positive ion chemical ionisation to qualitatively (full scan) and quantitatively (SRMS) determine tributyl tin, dibutyltin and mobutyltin in environmental waters. Detection... 

In some cases, ultrasonic nebulization or preconcentration is used to enhance detection limits. As, Se, and Sb were measured in cloud water detection limits were 20, 100, and 20 pg/mL, respectively, using pneumatic nebulization and four to five times lower using ultrasonic nebulization [311]. In another study [312], activated charcoal from a 1-L sample volume was used to preconcentrate Pd and Pt in fresh waters. Detection limits were 0.3-0.8 ng/L. An automated online preconcentration system based on a cationic resin (AG50W-X8) was used to measure Cd, Pb, Ni, Cu, and Zn. A preconcentration factor of 30 was obtained even with a sample throughput of 20 samples per hour [313]. 

ATR is a technique based on total internal reflections at the crystal surface. The infrared spectrum is measured from a very thin volume surrounding the infrared transparent ATR crystal. This technique is one of the best IR sampling techniques suitable for analyses of chemicals in water. Detection limit is less than 1 mg/ml for nerve agents (10). 

Chevalier et al. analyzed dipyridamole directly in the blood samples by a reversed phase high performance chromatographic method with fluori-metric detection [68], The HPLC system uses a 15 cm x 4.8 mm column packed with Lichrosorb RP8 (10 pm) and a mobile phase consisting of 40 60 v/v acetonitrile-water. Detection was made on the basis of fluorimetric detection at 410 nm (excitation at 305 nm). Depending on the model of the detector used, the detection limit of the method was between 2 x 10 13 and 2 x 10 15 mole injected. The precision was 5% for a concentration of 180 ng/mL of dipyridamole, and the method was used for a biodisposition study of dipyridamole in dogs. 

The control system of the plant provides a number of functionalities including start-up and shut-down, synchronisation to the grid, monitoring of the upstream water level, operation of the flow valve control of the turbine to match the availability of water, detection of faults and activation of necessary alarms. 

The water contamination level in solutions is usually measured by Karl Fisher (KF) titration. The water detection is based on the mechanism described below. In brief, the reaction includes two steps ... 

Gas-liquid chromatography [1/8 in. x 6 ft, 10% diethylene glycol succinate (LAC-728) column, 70°C] of cyclobutanone (99.2% pure) revealed the presence of small amounts of methylene chloride (0.6%) and cyclobutanol (0.2%). No cleavage product, 4-hy-droxybutyraldehyde, was found. The traces of water, detected by NMR spectroscopy using CD3COCD3 as a solvent, can be removed by drying over molecular sieves. 

Water detection to provide early wanung of leaks and other water hazards (e.g., condensahon)... 

Analysis of phenoxy acid herbicides in drinking water, detection limit 0.01 ig/l, qualitative and quantitative information, electronic archiving of data, 30 samples/day. 

Liras, J. L. and Anslyn, E. V. (1994) Exocyclic and Endocyclic Cleavage of Pyranosides in Both Methanol and Water Detected by a Novel Probe, J. Am. Chem. Soc. 116, 2645-2646. 

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