Optical length

DLs for impurities should correspond to less than 0.1% of the main compound " compounds that take effect in lower amounts may require lower DLs. For example, imipramine N-oxide hydrochloride impurities and salicylamide impurities have been determined at the 0.01% level. DLs and QLs in CE are generally to some extent higher (in concentration) than in HPLC because of the small optical path (50—100 pm) used for ultraviolet (UV) detection and small injected volume (2—20nl) compared with HPLC 10 mm optical length and 10—200 pi injected volume. ... 

When the optical length of the sample is much shorter than the other factors such as the length of the electron pulse, the response function takes on a Gaussian shape. As the optical length increases, the shape of the response function becomes trapezoidal. Furthermore, a thick sample causes the prolongation of the electron pulse by electron scattering, which leads to the degradation of time resolution. Therefore the experiment to observe ultrafast phenomena requires the use of a thin sample. 

The experiments were carried out using the subpicosecond pulse radiolysis system [77] described in Sec. 10.2.2 ( Subpicosecond Pulse Radiolysis ). Considering the signal intensity and the degradation of the time resolution, a sample cell with the optical length of 2 mm was mostly used. The sample was saturated by Ar gas to eliminate the scavenging effect by the remaining O2 gas. 

Fig. 4. Contact charge transfer complexes of nitrobenzene with VCZ and poly VCZ measurements of optical density at 437 mp. at room temperature Optical length 1 cm VCZ, -o- Poly VCZ in nitrobenzene, [NB] + [VCZ] = 0.3 M in benzene...

Fig. 6. Contact charge transfer complex between IBVE and AN. [IBVE] -f- [AN] = 0.3 M. Optical length 0.1 cm. Solvent n-hexane, O.D./[AN] = ey[IBVE]...

Absorbance (A) is defined by the Lambert-Beer law as log(7/70) and is equal to the product of sample concentration C (mol liter-1), molar absorbance e characteristic of the sample (liter mol-1 m-1), and the optical length L (m) of the sample ... 

Fig. 3. Evolution with increasing 7-dose of the absorption spectra of an aqueous solution containing [Au ] = [Ag ] = 5 x 10 mol L [PVA] = 0.1 mol L [propan-2-ol] = 0.2 mol L at pHlO. Optical length = 2 mm [modified with permission from Ref 72, copyright 1998 American Chemical Society], (a) Dose rate of 3.8 kGy.h h Inset plasmon absorption spectra of pure silver and pure gold nanoparticles, (b) Dose rate of 35 kGy.h h Inset Evolution with the dose of the absorbance at A = 480 nm.

Fig. 2 Cross-sectional diagram of a microchip. Two parallel 45° mirrors were fabricated at each end of the microchannel to increase the optical length (Reprinted from [17] with permission of Elsevier)...

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