Sample preparation for rapid, reproducible

SAMPLE PREPARATION FOR RAPID, REPRODUCIBLE CELL CULTURE... 

High-resolution nuclear magnetic resonance (NMR) spectroscopy is a relatively rapid technique and is highly robust in terms of reproducibility of results. The ubiquity of protons in cellular metabolites and the fact that other nuclei are observable by NMR (e.g., and mean that a relatively large number of different metabolites can be detected. Furthermore, the technique requires minimal sample preparation, and its nondestructive nature allows for more analyses to be... 

The methanol extraction method in our hands has the difficulty in that 1-5% of samples and blanks have very high values. We attribute the high values to contamination of the methanol with atmospheric moisture during sample preparation. Because of this problem and the need for a rapid and more reproducible method, we developed an alternative procedure for measuring the moisture content of stoppers using a drying oven purged into a Karl Fischer coulometric instrument. 

In using atomic spectroscopy analysis the sample introduction is an extension to sample preparation. To understand the limitations of practical sample introduction systems it is necessary to reverse the train of thought, which tends to flow in the direction of sample solution > nebulisation > spray chamber > excitation > atomisation. An introduction procedure must be selected that will result in a rapid breakdown of species in the atomiser to give reproducible results irrespective of the sample matrix. In designing an FI A system to carry out atomic emission and to generate efficient free atom production for excitation the following criteria must be adhered to as closely as possible ... 

Attempts to adapt MALDI-TOF to allow high-throughput analysis [48] have been made, but drawbacks still exist regarding pending sample preparation, matrix effects and the intrinsic inhomogeneity of the sample/matrix crystals combined with the positional resolution of the laser beam. Nevertheless, e.g. for oligonucleotides, it has been shown that autosampler arrays can provide rapid and reproducible results [49]. 

Nalorphine contains two hydroxyls, which are functional groups that can be used to check acetylation. If the surface areas or heights of the peaks for the internal standard change rapidly, it is probable that an error has been made in the sample preparation. This procedure at the same time gives a check of the statistical repeatability of the sample preparation. By plotting the peak areas in a control chart, the user can document the reproducibility of the method. A... 

With the growing demand for rapid chemical analysis to quantitate alkaloids, an array of chemical methods, each an improvement over the past, has been developed for five major opium alkaloids occurring in measurable quantity in Papaver. Among these, the reversed phase HPLC with a single run and with minimal sample preparation time is an easy and reproducible method for routine analysis of Papaver alkaloids. 

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