Bathing water sampling

After heating to 50 °C in a water bath, the sample was cooled to below room temperature and filtered. The residue was washed with two 5-mL portions of CCI4, and the combined filtrates were collected in a 25-mL volumetric flask. After adding 2.00 mL of the internal standard solution, the contents of the flask were diluted to volume with CCI4. Analysis of an approximately 2- tL sample gave LfD signals of f3.5 for the terpene hydrate and 24.9 for the camphor. Report the %w/w camphor in the analgesic ointment. 

This procedure has been utihzed to determine metal cations and anions in water sample [48,50,51], titanium in high-speed steel at a concentration level of 25 3 mg/g [22], heavy metals (20 to 400 mg/1) in electroplating waste waters [25], copper and nickel (5 mg/1) in metal electroplating baths on wedge-shaped plates [44], copper, lead, cadmium, or mercury in vegetable juices [29], and nickel (1 to 3.8 mg/1) in electroplating waste water of lock industries [42,47]. 

Measure 500 mL of water into a separatory funnel and add 150niL of dichloro-methane. Place the sample on a mechanical shaker and shake the funnel for 5 min. Drain the dichloromethane through a filter funnel containing ca 50 g of anhydrous sodium sulfate supported on a plug of glass wool. Re-extract the water sample with an additional 150 mL of dichloromethane for 5 min and filter the dichloromethane through anhydrous sodium sulfate. Combine the dichloromethane fractions and concentrate the extract to dryness in a rotary evaporator with a water-bath maintained below 40 °C. Proceed to Section 6.2.3. 

Brandt [200] has extracted tri(nonylphenyl) phosphite (TNPP) from a styrene-butadiene polymer using iso-octane. Brown [211] has reported US extraction of acrylic acid monomer from polyacrylates. Ultrasonication was also shown to be a fast and efficient extraction method for organophosphate ester flame retardants and plasticisers [212]. Greenpeace [213] has recently reported the concentration of phthalate esters in 72 toys (mostly made in China) using shaking and sonication extraction methods. Extraction and analytical procedures were carefully quality controlled. QC procedures and acceptance criteria were based on USEPA method 606 for the analysis of phthalates in water samples [214]. Extraction efficiency was tested by spiking blank matrix and by standard addition to phthalate-containing samples. For removal of fatty acids from the surface of EVA pellets a lmin ultrasonic bath treatment in isopropanol is sufficient [215]. It has been noticed that the experimental ultrasonic extraction conditions are often ill defined and do not allow independent verification. 

For the synthesis of materials, the reactants are placed in the copper crucible. An arc is struck by allowing the cathode to touch the anode. The current is raised slowly while the cathode is simultaneously withdrawn so as to maintain the arc. The arc is then positioned so that it bathes the sample in the crucible. The current is increased until the reactants melt When the arc is turned off, the product solidifies in the form of a button. Because of the enormous temperature gradient between the melt and the water-cooled crucible, a thin solid layer of the sample usually separates the melt from the copper hearth in this sense, the sample forms its own crucible and hence contamination with copper does not take place. Contamination of the sample by tungsten vaporizing from the cathode can be avoided by using water-cooled cathodes. The arc method has been successfully used for the synthesis of various oxides of Ti, V and Nb. A number of lower-valence rare-earth oxides, LnO, 5 have been prepared by arc fusion of LnjOj... 

Archaeological bone samples were treated for diagenesis before sample analysis. The bone samples were first mechanically cleaned with the Patterson NC-350 dental drill equipped with a carbide burr to remove any organic matter or contaminants. The mechanical cleaning also removed the layers of cortical bone most susceptible to diagenetic contamination, as well as all traces of trabecular bone. The bone samples were then chemically cleaned in an ultrasonic bath. The samples were first sonicated in water for 30 minutes, then rinsed and sonicated in 5% acetic acid for 30 minutes, and finally rinsed and sonicated with 5% acetic acid for 5 minutes (30, 53, 55, J9).The bone samples were dried for 1 hour at approximately 80°C. Finally, the bone samples were placed in a crucible and ashed at approximately 800°C for 10 hours. 

Irradiation procedures. Mesophase solutions and neat solid samples of BN were prepared and sealed under N2 or vacuum in Kimax capillary tubes. Isotropic samples were either degassed (freeze-pump-thaw techniques) and sealed in pyrex tubes or saturated with N2 in pyrex tubes. Nitrogen was bubbled through the latter solutions during irradiation periods. When ther-mostatted, samples were placed in a temperature controlled ( 1°) water bath. All samples were irradiated with a 450 W Hanovia medium pressure Hg arc and were stored at -30°C until their futher use. Usually, a "dark sample was prepared and treated in an identical fashion to the irradiated samples except that it was shielded from the light. JSN from each tube was recovered by either column chromatography (silica or alumina and pentane eluant) at 4°C followed by solvent removal at 0°C and reduced pressure or by hplc (tr-hexane) at room temperature followed by solvent removal at 0°C and reduced pressure. Neat solid samples were dissolved in one of either benzene, tetrahydrofuran or toluene and were frozen until analyzed. 

Lowering of oxygen levels is one way to increase the shelf life of pharmaceutical products. Lyman et al. [200] developed a method for the determination of oxygen in both aqueous and nonaqueous products. The method was applied to liquids and to solids with a melting point of 75 °C or less. A known amount of sample (2-3 g) in a 20-ml vial was first purged in an ice-water bath. The sample was then heated at 75°C with stirring and degassed... 

Extracts of the aqueous filtrate of water samples are in methylene chloride which is concentrated to approximately 10 mL by K-D or rotary evaporator prior to combining with the toluene extract of the particulates. If using K-D, the methylene chloride can be concentrated in a water bath instead of a heating mantle. 

A few tests were made in which the zeolite was pretreated to place it in essentially the Na form. In this method 30 g of zeolite and 200 ml of 1 mol 1 NaCl contained in a 250-ml beaker were placed in a household pressure cooker which was used as a water bath. The sample in solution was heated to v 120°C for 2 hours at a pressure of v 2 atm., using a method similar to that used by Starkey (12). A 5-minute cool-down time was then used before opening. Each sample was then washed thrice with distilled water, and the procedure repeated twice more before the zeolite was dried for subsequent use. 

All of the water samples were handled by liquid-liquid extraction (LLE) with hexane in the separation funnel. All glassware was thoroughly cleaned and rinsed with acetone and then hexane before use. The extracts were concentrated by rotary evaporator and then the sulfur-containing compounds were removed with elemental copper using ultrasonication bath. 

Total Organic Carbon (TOC). A standard method for TOC analysis (1) was modified by a special procedure for preparation of oily waste-water samples prior to the analysis. Two methods of oily water pretreatment were tested and used. In one method oily water samples were dispersed by mechanical stirring and ultrasonic vibration in an ultrasonic bath. The other method involved ultrasonic dispersion of oil in water by means of an ultrasonic probe (2). The best results in terms of emulsion stability and reproducibility were obtained using the ultrasonic probe method (Table I). 

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