Sensitivity-selectivity

The intrinsic charge-generation efficiency of polymers is often low and needs to be enhanced by the addition of sensitizers. The sensitizer can be dissolved in the polymer to enhance the bulk charge-generation efficiency of the polymer. Effective sensitizers include 2,4,7-trinitro-9- uorenone [129-79-3] (TNF), hiUerene, thiapyryhum dye, CdS nanoclusters, etc (Table 3). Molecular stmctures of selected sensitizers are shown in Figure 8. 

Fig. 8. Molecular stmctures of selected sensitizers (18) thiapyryhum dye [25966-12-5] , (19) difluoroboron-l,3-diphenyi-l,3-propanedionate (DPBDK) (20)...

A selective, sensitive and stability indicating reversed phase-HPLC method was developed for the determination of clarithromycin antibiotic in human plasma. 

In addition to reproductive effects, fish exposed to endocrine disrupters may have a decreased response to stress or decreased growth and metabolism which can affect their ability to survive, or to defend themselves against predators. All of these factors can affect the ability of the species to survive and to reproduce itself in sufficient numbers to maintain the stocks on which our commercial and sport fisheries are based. Not all fish species will be equally susceptible to the effects of endocrine disrupters. Selective sensitivity to such effects, especially those affecting reproduction, may well lead to major changes in the flora and fauna of some of our major aquatic ecosystems as the balance between fish, mammals, invertebrates and plants, and between predators and prey, is destabilised... 

There are various ways in which CMEs can benefit analytical applications. These include acceleration of electron-transfer reactions, preferential accumulation, or selective membrane permeation. Such steps can impart higher selectivity, sensitivity, or stability to electrochemical devices. These analytical applications and improvements have been extensively reviewed (35-37). Many other important applications, including electrochromic display devices, controlled release of drugs, electrosynthesis, and corrosion protection, should also benefit from the rational design of electrode surfaces. 

Studies of the polarized IBTILE provide a fundamental knowledge that makes it possible to explain phenomena occurring at the membranes of ion-selective electrodes. In addition, the rates of ion transfer and assisted ion transfer reactions are proportional to concentrations, which is a basis of an amperometric ion-selective (sensitive) electrode. 

Tandem mass spectrometry is the ultimate problemsolving tool for chemical analysis when enhanced specificity, specificity, selectivity, sensitivity, and/or speed are required, but at a price. This is primarily due to the capacity of MS/MS to obtain spectra of selected precursor ions in complex mixtures. Advantages in using MS/MS are ... 

For the quality of a sensor, not only the transduction is essential but also the sensitive layer. In addition, it determines selectivity sensitivity, stability... 

In this way, it is possible to reach an extremely high selective sensitivity down to 1 part in 1015, which in 14C dating corresponds to being able to date samples about 50 000 years old. Moreover, modern systems can measure isotopic ratios in modern carbon, both C/ C and C/ C, with an ultimate precision as good as 2%o and l%o, respectively. The former value corresponds to determining the conventional radiocarbon age with an absolute error, smaller than in the past, better than 20 years, while the l%o precision for the 13C/12C allows an adequate correction for isotopic fractionation effects. Even in routine measurements, at least in the case of historical samples, a precision of 5%o in the 14C/12C measured value is standard, corresponding to an uncertainty in the radiocarbon age of 40 years.[27]... 

Erhardt-Zabik, S., J.T. Watson, and M.J. Zabik. 1990. Selective sensitivity of highly chlorinated species in negative ion mass spectrometry implications for complex mixture analysis. Biomedic. Environ. Mass Spectrom. 19 101-108... 

A simple and rapid RP-HPLC method was developed for the determination of retinoid in galenicals. Commercial preparations were diluted, filered and used for separation. Measurements were carried out in an ODS column (150 X 4.6 mm i.d. particle size 3 /xm). Solvents A and B were methanol-10 mM ammonium acetate (75 25, v/v) and methanol-THF (84 16, v/v), respectively. The flow rate was 0.8ml/min. Gradient conditions were 0-25 min, 0 per cent B 35 min, 100 per cent B, isocratic for 10 min. Typical chromatograms are shown in Fig. 2.37. The repeatability of peak area ranged between 0.48 -3.2 per cent for UV-DAD and 0.57 - 3.1 per cent for fluorescence detection. The reproducibility varied between 0.26 - 4.6 per cent. It was found that the method is precise, selective, sensitive and linear, therefore, it can be employed for the routine quality control of this class of drags [85],... 

HP-jS-CD were added. All compounds were resolved in 20 min (see Figure 5). The data indicated that the validated method offered equivalent and complementary information, in terms of selectivity, sensitivity, accuracy, linearity, and precision, to that of an established gradient LC method employed for similar purposes. Ragaglitazar is a dual peroxisome proliferator-activated receptor ot and y agonist intended to restore insulin sensitivity and correct diabetic dyslipidemia. A chiral CZE method combining two CDs, sulfobutylether-jS-CD and dimethyl-/i-CD, lent itself to the analysis of ragaglitazar, its distomer (the (+)... 

Separation and detection techniques for antibacterials in food mainly focus on the use of LC coupled to MS or tandem MS. Nevertheless, recent studies have suggested capillary electrophoresis coupled to laser-induced fluorescence (LIE) as a way of improving sensitivity [49], HRLC coupled to microTOF-ESI-MS as a highly selective, sensitive, and quick screening method for 100 veterinary drugs in fish, meat, and egg samples [195], and nanoscale LC coupled to UV or ion trap MS, with LODs in the range 0.01-0.51 pg/L (nanoLC-MS) and the possibility that even lower limits could be achieved by using triple quadrupole MS [59]. 

Because of its exceptional selectivity, sensitivity and speed, IC is particularly suited to applications involving analysis of anions and cations in wastewater, natural waters, source effluents, workplace environments, ambient air and rain water. The analysis of organic as well as inorganic ions can be performed by 1C. Table I is a growing list of ions which have been successfully separated and detected. The principles of IC and selected applications to environmental pollutants are described in this paper. 

Mass-produced cantilever sensors, however, have the potential to satisfy the conditions of selectivity, sensitivity, miniature size, low power consumption, and real-time operation [5, 6], Microcantilevers are micromachined from silicon or other materials and can easily be fabricated in multiple-element arrays. They resemble miniature diving boards measuring 100 to 200 pm long by about 20 to 40 pm wide by 0.3 to 1 pm thick and having a mass of a few nanograms. Their primary advantage originates from their sensitivity, which is based on the ability to detect their motion with subnanometer precision. 

Hayazawa, N., Watanabe, H., Saito, Y, and Kawata, S. 2006. Towards atomic site-selective sensitivity in tip-enhanced Raman spectroscopy. J. Chem. Phys. 125 244706. 

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