Some New Stable Ultraviolet Transmitting Solution Filters

Abstract

Abstract— For use with very intense light source, e.g. flash lamps and high‐pressure arcs, some new stable transmission filters for the U.V. were developed. All filters were composed to give maximum transmittance in the desired bands together with optimum absorbance of the visible light, at an optical path of 1 cm. The filters described are easy to prepare and have considerably better properties than the well known NiSO4‐‐CoSO4 filter and other filter combinations. During initial irradiation with high‐intensity light sources the transmittance of the freshly prepared filter solutions increases slowly till maximum transmittance is attained. The position of the transmission bands, however, does not change. Based on the fact that the 6700 Å absorption band of some non‐aqueous solutions of CoCl2 has an extinction coefficient about a hundred times larger than the 5100 Å absorption band of the aqueous solution with the same concentration, filter solutions were developed for the following transmission bands: 2600–3900 Å, 2900–3900 Å and 3100–3900 Å with transmission maxima of 90, 90 and 75 per cent respectively, and 2600–4600 Å, 2900–4500 Å and 3100–4600 Å with transmission maxima of 95, 95 and 90 per cent respectively, at an optical path of 1 cm.

NEAR‐INFRARED DETECTION OF SINGLET MOLECULAR OXYGEN PRODUCED BY PHOTOSENSITIZATION WITH PROMAZINE and CHLORPROMAZINE

“…2 Table 1. A liquid filter solution described by Wladimiroff (1966) containing 55% dimethylformamide, 0.42 M NiCI2, 0.85 M CoCI, and 1 M HCI in water was used with the Hg arc lamp to pass UV light between 290 nm and 390 nm; the fluence rate at the point of entry to the rectangular cuvette was 12 kW m-, as measured with a Yellow Springs Instrument Company (Yellow Springs, OH) model 5225 radiometer. Ten centimeters of water were used to block infra-red radiation in the excitation light path and a Corion LL-950 filter was used to eliminate visible and ultraviolet light from the emission signal.…”

Triplet Yield of Merocyanine 540 in Water Is Wavelength Dependent

“…Filter B is a mixture of 65% ethanol (99%, Merck, Darmstadt, W. Germany) and 35% H20 (1 mol dm-3 HCI, Merck, Darmstadt, W. Germany). This filter cuts off wavelengths shorter than 258 nm and longer than 390 nm (Wladimiroff, 1966). Filter C is a 0.21 mol dm-3 CuCI, and 1.06 mol dm-3 CaCl, aqueous solution and removes wavelengths below 380 nm and above 700 nm (Hoebeke et al, 1988).…”

The Kinetics of the Reaction Between the Hydrated Electron and Amino Acids Studied by Flash Photolysis

“…The transient absorption change was studied at 720 nm, where the hydrated electron absorption spectrum has its maximum [7], using an Osram XBO 450 monitoring lamp, a Zeiss MM 12 monochromator, an EM1 9558 QB photomultiplier and a Tektronix 565 oscilloscope. Liquid filters in a jacket surrounding the solutions restricted the excitation light to 220 < A < 360 nm (NiS0,-CoSO, in water [8]) for phenylalanine and to 260 < A < 380nm (NiC1,-CoCI, in ethanol [9]) for tyrosine and tryptophan.…”