Alternative Lamps

There are a number of different lamps available on the commercial side that claim to be natural or daylight or sun lamps for reproducing some or all of the benefits of natural sunlight, even Most are poor substitutes. 

As was previously mentioned, specialty lamps available from only one source can be a problem. Lamp A and C manufacturer s original lamps disappeared from the marketplace for a time and changes were made in their replacements. Sole source lamps are not very reliable international standards. 

A number of basic questions regarding sole source lamps arise. Who will validate the lamp(s) Will these lamps be evaluated as a yes/no problem as advocated by Sager et al. (30) or on a qualitative and quantitative scientific basis as any other analytical method for impurities  

If the ICH guideline is to reach its objective of reducing the unnecessary duplication of efforts and speed up the review process, revision of the guideline is of course necessary and the use of broad qualifiers such as similar must be replaced by definite standards as is common in all compendia. 

International Conference on Harmonisation (ICH). Guideline for the Photostability Testing of New Drug Substance and Products. Federal Register 1997 62 27115-27122. 

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The photo cell senses light of all wavelengths that is generated by fluorescence but the wavelength of the excitation light can only be changed by use of an alternative lamp. This simple type of fluorescence detector was the first to be developed, is relatively inexpensive, and for certain compounds can be extremely sensitive. Typical specifications for a fluorescence detector are as follows ... 

Film samples were also exposed to UV light on RS sunlamp turntables. These consist of two RS sunlamps mounted 10 inches above 12 inch diameter turntables which were rotated at about 5 rpm. Alternate lamps were replaced every week. 

The Effect of Light Source on Curing Rate. As stated earlier, Sylvania F4T5 was the lamp used in the standard Photo-DSC measurements and this lamp had a broad emission spectrum centered at 350 nm. When an alternate lamp (GE F4T5) with an emission peak at 365 nm was used, the ranking of initiators, in terms of peak time, remained the same. Table III lists representative results from these experiments. The emission spectrum of this GE lamp was also shown in Figure 3. 

A suitable heating lamp or other heating device. The author has found the 250 watts vertical pattern radiator lamp ( sausage lamp) or, alternatively, the Santon 250 or 500 watts immersion heater f to give excellent results. 

On the other hand, 2-arylthiazoles are easily isomerized to 3-aryliso-thiazoles in 407o yield upon irradiation with a high-pressure mercury lamp, in benzene solution in the presence of iodine (738). A valence bond isomerization was proposed among several alternatives to account for these results. 

Aluminum is best detected quaUtatively by optical emission spectroscopy. SoHds can be vaporized direcdy in a d-c arc and solutions can be dried on a carbon electrode. Alternatively, aluminum can be detected by plasma emission spectroscopy using an inductively coupled argon plasma or a d-c plasma. Atomic absorption using an aluminum hoUow cathode lamp is also an unambiguous and sensitive quaUtative method for determining alurninum. 

As an alternative to radiation, a stain such as ethidium bromide is used to visualize DNA. The ethidium may be incorporated into the stmcture of DNA either before or after electrophoresis. The gel is then visualized under a fluorescent lamp. 

The simplest and of course the most inexpensive external light source is the sun. This source, however, is not always as dependable and reproducible as the photochemist would like. Alternatively, a sun lamp, whose... 

Safety lamp mine. Alternative name for gassy mine, implying possible presence of methane. 

The procedure is strictly analogous to that used for absorbance measurements in UV and visible molecular spectrometry (p. 355). To avoid interference from emission by excited atoms in the flame and from random background emission by the flame, the output of the lamp is modulated, usually at 50 Hz, and the detection system tuned to the same frequency. Alternatively, a mechanical chopper which physically interrupts the radiation beam, can be used to simulate modulation of the lamp output. 

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