Paper strip for

Zinc Costing of Ca.pa.citors, In the zinc coating of paper strip for capacitors, the paper strip is fed from air through locks into a vacuum environment. There, it is coated by thermally evaporated zinc. The rate of evaporation is so high that contamination of the zinc vapor is excluded. The paper is fed at the maximum rate permitted by its own strength. 

The use of 3,4-dihydro-2.//-pyrido[l,2-a]pyrimidin-2-one 675 and its alkyl derivatives in test paper strips for the detection of bilirubin in body fluids, especially in urine, has been reported [83JAP(K)83/18168]. 

Universal indicator paper strips for pH ranging from 0 to 14 and a reference color chart... 

To remove heat and stem its excessive buildup, the electrophoretic medium must be cooled. Paper strips, for example, are sandwiched between thin glass plates which are water cooled gel-containing tubes or annuli can likewise be cooled by water or petroleum ether. 

There need not be a mark on the paper strip for every curve on the chart, because some lines may have zero intensity or be too weak to be observed. 

Specimen collection for amino acids is comprehensively covered in Chap. B. Filter paper blood spots (PKU cards) are increasingly used for blood collection. Urine specimens for the testing of purines and pyrimidines, and for acylglycines are typically frozen and shipped on dry ice. They can also be applied to filter paper strips. For further details, refer to Chap. 21 and refs. 7 and 8. 

Now place 35 ml. of the mixed solvent (C) in the clean cylinder E, and suspend the strip, as described above, to the horizontal arm of G (Fig. 25(A)) adjust the position of the strip so that, when the bung is firmly in position, the bottom of the paper-strip is about 5 mm. above the solvent. Place the cylinder for 5-8 hours in a draught-free place, such as a cupboard, where the temperature is reasonably constant. 

Now lower the paper-strip, which has become saturated with the solvent vapour molecules, so that it dips about 5 mm. into the solvent. Then close the cylinder, and set it aside as before for 12-18 hours, by which time the solvent will have risen about three-quarters of the height of the strip. 

Note. The period of 5-8 hours recommended above for attaining an equilibrium between the vapour molecules of the mixed solvent and those absorbed by the paper strip is essential if accurate R values are required for identification of mixed amino-acids. To illustrate the separation, as in the above experiment, this period may be reduced to about 2 hours. 

This experiment requires less time than the former, for the paper strip comes into equilibrium with the solvent vapour much more rapidly, and can then be inserted into the solvent without intermediate drying. 

Chemical indicators for dry-heat steriliza tion are available either in the form of pellets enclosed in glass ampuls, or in the form of paper strips containing a heat-sensitive ink. The former displays its end point by melting, the latter by a color change (see Chromogenic materials). 

For many years atactic polypropylene was an unwanted by-product but today it finds use in a number of markets and is specially made for these purposes rather than being a by-product. In Europe the main use has been in conjuction with bitumen as coating compounds for roofing materials, for sealing strips where it confers improved aging properties and in road construction where it improves the stability of asphalt surfaces. Less important in Europe but more important in USA is its use for paper laminating for which low-viscosity polymers are used, often in conjunction with other resins. Limestone/atactic... 

The paper. strips used in the colorimetric method are impregnated with such dyes that the color of the test paper is dependent upon the pH of the medium in which the paper is placed. A standard color chart is supplied for comparison with the test strip. Test papers are available in a wide range type, which permits estimating pH to 0.5 units, and in narrow range papers, with which the pH can be estimated to 0.2 units. 

Leaves are stripped for 30 minutes in the usual 2-quart wide-mouthed Mason jars. Instead of a waxed paper gasket, however, 2 squares of No. 300 M.S.T. cellophane topped by a square of white nylon are used, as the benzene would disintegrate the wax paper during this longer stripping period. The entire 250 ml. of benzene are added at once, the... 

The main devices used for mosquito protection in households have been mosquito coils, electric mosquito mats, and liquid vaporizers, all of them methods that vaporize insecticides into the air using heating by means of fire or electricity to control the insects. In recent years, new anti-mosquito products have been commercialized such as fan vaporizers, paper strip type emanators, and resin net type emanators which vaporize insecticides without heating. In all of these products pyrethroid insecticides are used as active ingredients because they are superior in what is called knockdown effect, where noxious insects are rapidly paralyzed and cannot bite, and have a high level of safety for humans. 

In this method the sediment is mixed with sodium sulphate and extracted with n-hexane. A portion of the extract is applied to a paper strip which is then eluted with petroleum ethenbenzene (35 65) for 60 seconds. Viewing of the strip under ultraviolet light reveals a blue fluorescent spot indicating the presence of oil in the sediment. 

The prepared Ampholine gel is set up in the tank and thick filter paper strips are soaked with either the anodic or cathodic electrolyte and placed along the appropriate edge of the gel. The samples may be applied either to small filter paper squares laid on the surface of the gel or, for bulk preparative work, incorporated in the gel. The appropriate voltage is applied through terminals attached to the electrode wicks and after about 30 min can be switched off to permit the removal of the sample filter papers before continuing the separation. 

Colorimetric field tests for TATP and HMTD were described in Section 5 dealing with peroxide-based explosives. This group contains Keinan s PEX [85] (E. Keinan, Personal Communication, February 2006) and the kit developed by Schulte-Ladbeck et al., which involves also a preliminary stage to avoid falsepositive responses by non-explosive peroxides [86]. The color change of molybdenum hydrogen bronze suspension upon reaction with TATP was recommended also as a field test. Exposure of filter paper strips which were soaked in butanol suspension of the molybdenum compound to TATP or hydrogen peroxide vapors rapidly bleaches the blue color [87, 88]. 

The first work on pKa determination by zone electrophoresis using paper strips was described by Waldron-Edward in 1965 (15). Also, Kiso et al. in 1968 showed the relationship between pH, mobility, and p/C, using a hyperbolic tangent function (16). Unfortunately, these methods had not been widely accepted because of the manual operation and lower reproducibility of the paper electrophoresis format. The automated capillary electrophoresis (CE) instrument allows rapid and accurate pKa determination. Beckers et al. showed that thermodynamic pATt, (pATf) and absolute ionic mobility values of several monovalent weak acids were determined accurately using effective mobility and activity at two pH points (17). Cai et al. reported pKa values of two monovalent weak bases and p-aminobenzoic acid (18). Cleveland et al. established the thermodynamic pKa determination method using nonlinear regression analysis for monovalent compounds (19). We derived the general equation and applied it to multivalent compounds (20). Until then, there were many reports on pKa determination by CE for cephalosporins (21), sulfonated azo-dyes (22), ropinirole and its impurities (23), cyto-kinins (24), and so on. 

Figure 4.12 — (A) Flow-cell for the simultaneous determination of four analytes (1) ion-selective electrodes (2) reference electrode (3) Pt wire for grounding (4) Teflon gasket (5) carrier (6) inlet for reference solution (7) waste (8) screws (9) diecast box (10) rubber sheet for sealing. (B) Seven-electrode holder (the reference electrode is placed from the top into die central bore). ISEs for Na, K, Ca ", NOj", Cr, and HCO, (NH, electrode with internal buffer of 0.1 mmol/L NaHCOj) are placed horizontally around the reference electrode, the metal waste tubes being connected to the waste via filter-paper strips. (Reproduced from [124] and [108] with permission of Elsevier Science Publishers and VCH Publishers, respectively).

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