For these analytes, the peak areas were similar for samples worked up using either of the two cartridges for SPE-2 (Fig. 3b).
Sample handling and sample work up; for example, avoidance of polycarbonate-containing plastic tools such as tubes or syringes.
Besides these biological factors, other effects present in the data set are: 4. Technical variation; this originates from, for instance, sampling, sample work-up and analytical errors.
Overall, 37percentt of the sample works for companies with at least 5,000 employees and 51percentt for firms that employ fewer than 1,000 individuals.
For this purpose, two sample work-up methods were developed, using ethyl acetate extraction orethyl chloroformate derivatization.
"Do the same things you would do offline — you're still going to interview, still going to get references and still going to ask for samples of work," Mr. Swart said.
The addition of Alexa 594 as a dye-label for an additional – third – target sample works within the framework of more commonplace Cy5/Cy3 labelled target sample combinations.
For urine samples, working standards and quality controls were evaporated under a stream of nitrogen and reconstituted in 100 μL of tenfold diluted blank urine.
For plasma samples, working standards and controls were evaporated under a stream of nitrogen and 100 µL of control plasma was added for calibrants and quality control samples preparation, the samples were mixed vigorously for 5 10 s using a platform (vortex) mixer.
In preparation for sampling, the working table was covered with a large sheet of clean white paper.
