Degradation sensitization

Magnetic sector mass spectrometers accelerate ions to more than 100 times the kinetic energy of ions analysed in quadrupole and ion trap mass spectrometers. The higher accelerating voltage contributes to the fact that ion source contamination is less likely to result in degraded sensitivity. This is particularly important for analysis that requires stable quantitative accuracy. 

Pigment-Sensitized Dye Photooxidation. Dye degradation sensitized by titanium dioxide is a recognized phenomenon (16). 

A mechanical balance should be in its arrested position when you load or unload the pan and in the half-arrested position when you are dialing weights. This practice minimizes wear on the knife edges, which degrades sensitivity. 

Generally, dissolved solid concentrations should be kept below 0.2% for ICP-MS. Higher dissolved solid concentrations can lead to deposition of sample on the sampling and skimmer orifices, partial orifice plugging, or deposition of material on ion lenses that degrade sensitivity and medium-term to long-term precision. Furthermore, relatively small concentrations of a heavy element (100 ppm or greater) in a sample can cause a decrease in analyte sensitivity, particularly... 

Fig. 1.5. Ion image of S+ (a) produced from CS2 in an intense laser field (0.36PW/cm2), recorded with a position-sensitive detector (PSD). The small hole in the central part of the accumulated image is ascribable to the degraded sensitivity of the central part of the detector. The coincidence ion images of S+ (b-d), and the corresponding kinetic energy release distributions (e-f) obtained for the (1,1), (1,1,1) and (1,1,2) Coulomb explosion pathways, respectively...

LSPR-based sensitivity enhancement using surface-relief nanostructures has been confirmed experimentally in a few smdies to date. In the experiments conducted by Byun et al. [26], ethanol-water mixture at varied ethanol concentration was used to estimate the sensitivity enhancement by periodic nanowires atA = 200 nm and 500 nm respectively as 44% and 31% over conventional structures, as shown in Fig. 7. Note that the sensitivity enhancement for bulk index measurement is relatively limited compared to layered bio-molecular interactions, because of reduced index contrast against ambience. It was also found that surface roughness can degrade sensitivity performance [27]. Measurement of the DNA hybridization process was performed using nanoposts at A = 110 run and presented more than fivefold sensitivity improvement, as shown in Fig. 8 [28]. 

Several types of spectra are referred to in the pharmaceutical photostability literature, including emission, absorption, activation, action, and spectral power distributions (SPDs). Each of these terms has a specific meaning and use. For example, the absorption spectrum of a typical compound is often assumed to represent its degradation sensitivity, which is not always the case. This assumption arises because of the fact that in order for a compound to react with radiation, it must first absorb it and a good first indicator of these active wavelengths are its absorption spectra. 

Fragile, delicate, easily breaks down Degrades, sensitive to contamination Deteriorates rapidly, has to be handled with care... 

Solid-state reactions usually require higher-activation energy compared to solution-state reactions due to the constraints of the crystal lattice. What is very often underestimated is the negative effect of the bulk lattice on the crystal surface. It can be expected that the degradation-sensitive reaction sites in the solid state will be more vulnerable on the crystal surface, where particles are in direct contact with the external environment. Clearly environmental factors such as temperature, humidity, and interactions with excipient particles may have a negative effect on the rate of chemical degradation occurring on a crystal surface. Stractural information on the particle surfaces can potentially provide additional information about the exposure of reaction-sensitive sites. 

BIOPOLYMERS Xanthan Scleroglucan - high productivity in brine - resistant at high shear rates and temperature - adsorption (salt) - problematic injec-tability - sensitive to microbial degradation - sensitive to oxygen... 

ICl rapidly undergoes electrophilic substitution predominantly with tyrosine residues of the target molecule. The reaction is fast and finishes within a few seconds. The optimum conditions for the mild incorporation of radioiodine into proteins are a low temperature of 4°C, a pH value in the range of 6-8, and a short reaction time of <1 min. Chloramine-T often degrades sensitive peptides. This has to be prevented by the addition of a reducing agent. 

Spray-dried particles have also been incorporated into effervescent products. In one study, spray drying was used to protect a degradation-sensitive active by coating fine particles of the drug with a sugar alcohol solution (50). In vivo results of tablets made using the spray-dried particles combined with coated citric add and sodium bicarbonate revealed that the active was rapidly absorbed from the tablet. 

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