Sensitivity improvement

Before such sensitivity improvements, high energy illumination was requited to give enough exposure intensity. 

Column internal diameter Volumetric flow rate Injection volume UV-deteaor cell volume Sensitivity improvement... 

Practical constraints prevent this technique from living up to its potential, even in this, the era of the superconducting probe. Until sensitivity improves by at least another order of magnitude, the INADEQUATE experiment will remain just that - inadequate by name and by nature. 

Wiebolt RC, Adams GE, Later DW. 1988. Sensitivity improvement in infrared detection for supercritical fluid chromatography. Anal Chem 60 2422-2427. 

Gassman and co-workers have recently investigated the photoinduced cy-clization of y,5-unsaturated carboxylic acids to y-lactones [100]. 5-Methyl-4-hexenoic acid 51 is converted into the radical cation 52. The cyclization of 52 is expected to yield the distonic radical cations 53 and 54, which leads to the anti-Markonikow products 55 and 56 in ratio 5 1. Fine-tuning of the sensitizer improved combined yields up to 89% [101],... 

It effectively controls blood pressure over 24 hours suppressing early morning BP rise. It increases insulin sensitivity, improves lipid profile. 

Higashi and coworkers [28] used 2-hydrazino-l-methylpyridine (HMP) derivatization to introduce a positively charged moiety in testosterone and dihydrotestosterone (DHT) to achieve a sensitivity improvement of 70- to 1600-fold compared to underivatized molecules in ESI. However, they found the derivative was unsuitable for di-keto steroids such as androstenedione and progesterone, so this form of derivatization is unlikely to be widely accepted. Separable syn- and anti- (E and Z) stereoisomers are formed using this derivative. Preparation is as follows a solution of 10 pg HMP in 50 pi ethanol containing 25 pg TFA was added to the steroid dissolved in 30 pi ethanol. After heating for 1 h at 60 C, the solvents can be removed and sample injected. 

Electrochemical detection has also been further recommended as an excellent alternative for the determination of seven sedatives and carazolol in swine liver and kidney (523). In this study, significant selectivity and sensitivity improvements compared to existing methods have been reported. 

Standard heat capacities of transfer can be derived from the temperature dependence of standard enthalpies of solution (8). While this technique can give general trends in the transfer functions from water to mixed solvents (9), it is not always sufficiently precise to detect the differences between similar cosolvents, and the technique is rather laborious. Direct measurements of the difference between heat capacities per unit volume of a solution and of the solvent a — gq can be obtained with a flow microcalorimeter (10) to 7 X 10 5 JK 1 cm-3 on samples of the order of 10 cm3. A commercial version of this instrument (Picker dynamic flow calorimeter, Techneurop Inc.) has a sensitivity improved by a factor oi about two. 

USP 2464777(1949) CA 43,6828(1949) [Addn of 4-12% NC(having a fiber length of 30-250ft) to LA reduces its sensitivity improves its loading characteristics for use in detonators]... 

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