Residues on glass

The last example in this section is taken directly from a Philips production site. The product in question consists mainly of plastic materials and glass attached by various glues. The product also contains moving and rotating metal parts which need to be lubricated. Unfortunately, the process technology of the product is confidential and cannot therefore be shown, but the example demonstrates how ToF-SIMS can be used to solve real production problems. 

By optical inspection of the glass parts of products that had failed in a lifetime test a contamination layer was detected, which in. some areas was as thick as a few pm. In order to characterize the contaminant, IR and XPS measurements were performed. ToF-SIMS was not chosen in the first place because the problem seemed neither to require very sensitive analysis nor to be related in any way to the outer monolayer of the glass. The analyses showed that the material must be organic in origin, most probably based on aliphatic hydrocarbons (single C l.v peak in the XPS spectrum, CH vibrations in the IR spectrum), but no further information could be obtained (no loss features or chemical shifts in the XPS spectra, no typical bonds in the IR spectra). The diagnosis aliphatic hydrocarbon still included several glues and fats as possible contamination sources. 

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The aforementioned series of reactions provides a basis for a colorimetric analytical method for Compound 118 in which the commonly used agricultural chemicals do not interfere. The procedure described herein permits the estimation of as little as 10 micrograms of Compound 118, and has been successfully applied to the analysis of this insect toxicant in insecticidal dusts, in film residues on glass and paper, in human and animal urine, and in mixture with other insecticides. Application of this procedure to the determination of Compound 118 in milk and in spray and dust residues on plants appears promising. 

Mosher, D.R. and Kadoum, A.M. Effects of four lights on malathion residues on glass beads, sorghum grain, and wheat grain,... 

P. C. Andrews and J. E. Dixon, A procedure for in situ alkylation of cysteine residue on glass fiber prior to protein microsequence analysis, A aZ. Biochem. 161 (1987), 524-528. 

Mosher, D.R. and A.M. Kadoirrrt. Effects of Forrr Lights on Malathion Residues on Glass Beads, Sorghum Grain, and Wheat Grain, J. Econ. Entomol, 65 847-850 (1972). 

Organisms placed in contact with isotope residue on glass plate. (49 )... 

Pimelic acid. Heat a mixture of 18 g. of pentamethylene dicyanide and 250 g. of 50 per cent, sulphuric acid by weight in a 750 ml. round-bottomed flask under reflux for 9 hours. INIost of the pimehc acid separates from the cold reaction mixture. Filter oflF the crystaUine acid upon a sintered glass funnel. Saturate the filtrate with ammonium sulphate and extract it with three 50 ml. portions of ether. Dissolve the residue on the filter (which is shghtly discoloured, but is fairly pure pimehc acid) in the combined ethereal extracts, dry with anhydrous sodium or magnesium sulphate, and remove the ether by distiUation. Recrystallise the residual sohd acid from benzene containing 5 per cent, of ether. The yield of pure pimehc acid, m.p, 105-106°, is 22 g. 

Fig. 8. Drying time and rate profiles for leather pasted on glass plates and dried in two temperature stages. Gas velocity = 5 m/s in parallel flow, 71°C in the first stage, 57°C in the second. The falling rate, drying rate is proportional to residual moisture content.

Protein residues, eg, soft-boiled egg yolk, are difficult stains to handle. If the stains are not totally denatured, proteases can decompose them. There are commercial proteases with a high temperature optimum (60°C) that can remove most protein soils in a dishwasher (63). Patents on the use of Upases in ADDs have claimed that Upases can reduce the formation of spots and films on glasses (62,64—66) however, no commercial appUcation of Upases in ADDs has been implemented. 

Phosphorus pentabromide [7789-69-7] M 430.6, m <100 , b 106 (dec). Dissolved in pure nitrobenzene at 60°, filtering off any insoluble residue on to sintered glass, then crystallised by cooling. Washed with dry Et20 and removed the ether in a current of dry N2. (All manipulations should be performed in a dry-box.) [Harris and Payne J Chem Soc 3732 1958]. Fumes in moist air because of hydrolysis. HARMFUL VAPOURS. 

Artifacts introduced through sample preparation are common materials these may be bits of facial tissue, wax, epithelial cells, hair, or dried stain, all inadvertently introduced by the microscopist. Detergent residues on so-called precleaned microscope slides and broken glass are common artifacts, as are knife marks and chatter marks from sectioning with a faulty blade, or scratch marks from grinding and polishing. 

Ascher and Nemny 495) found that residues of triphenyltin acetate on glass, resulting from the evaporation of acetone solutions thereof, were, on contact to houseflies, less toxic with rising concentration. As triphenyltin acetate is likely to be a self-associated polymer in the solid state [similar to trimethyltin acetate (355)] and in concentrated solutions, it was suggested 495) that the monomer, which exists in dilute solutions, is toxic to insects, and the polymer, nontoxic. Interestingly, in this connection, a triphenyltin methacrylate copolymer has 470) a very low mammalian toxicity (acute, oral LDso for mice >2000 mg/kg). 

Weigh 20 g (fresh weight) of chopped and homogenized plant samples into a 300-mL Erlenmeyer flask. Add 80 mL of acetone and shake the flask vigorously for 30 min with a shaker. In the case of brown rice and pea, add 20 mL of water to 10 g of sample and allow to stand for 2 h before adding 80 mL of acetone. Filter the extraction mixture by suction through a glass filter and re-extract the residue on the filter with 50 mL of acetone, then filter the mixture by suction. Concentrate the combined filtrate in the 300-mL of round-bottom flask to remove acetone at below 30 °C after addition of a 25% aqueous solution of potassium carbonate (0.2 mL). 

Homogenize 50 g of a prepared sample with a solution containing 50 mL of borate buffer (pH 10) and 50 mL of acetone in a blender for 5 min. Pour the homogenate into an Erlenmeyer flask, add 50 mL of acetone and shake the flask for 10 min using a shaker. Filter the aqueous acetone extract through a 25G-4 glass filter overlaid with 3 g of Celite. Wash the residue on the filter with 50 mL of acetone. Combine the filtrates and remove acetone by rotary evaporation. Transfer the residue with 5 mL of 4% sodium dodecyl sulfate aqueous solution into a separatory funnel, extract the solution with two portions of 50 mL of dichloromethane and collect the organic... 

Parathion spray residue on the surface of the fruit was determined by the method of Averell and Norris (2). Samples of sufficient size of firm fruit completely to fill 1-gallon wide-mouthed glass jars were selected for analysis. 

Water repellency is achieved by making the surface hydrophobic - ysv has to be reduced as much as possible if ysv - ySL is negative, 9 > 90° C - water repelling materials include waxes, petroleum residues and silicones for example, if =SiOH groups on glass or Si02 surfaces have reacted with silanes to form =SiO—Si—Alkyl... 

A 2-1. two-necked round-bottomed flask fitted with a mechanical stirrer and a reflux condenser is charged with 40.0 g. (0.22 mole) of p-cyanobenzenesulfonamide (Note 1), 600 ml. of 75% (v/v) formic acid, and 40 g. of Raney nickel alloy (Note 2). The stirred mixture is heated under reflux for 1 hour (Note 3). The mixture is filtered with suction through a Buchner funnel coated with a filter aid (Note 4), and the residue on the funnel is washed with two 160-ml. portions of 95% ethanol. The combined filtrates are evaporated under reduced pressure with a rotary evaporator (Note 5). The solid residue (Note 6) is heated in 400 ml. of boiling water and freed from a small amount of insoluble material by decantation through a plug of glass wool placed in a filter funnel. The filtrate is chilled in an ice bath and the precipitate is collected by filtration with miction, washed with a small amount of cold water and dried at 50°... 

Finally, our observations regarding the longterm impact of alkali ion exchange on glass dissolution now provide a mechanistic basis for the empirical residual rate of reaction appended to the TST rate law articulated by Grambow (1985). The residual rate was appended to prevent calculated glass dissolution rates from dropping to zero under silica-saturated conditions, which is not in accord with experimental observations. 

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