Sample primary

The primary sample types used for field spiking were freshly prepared soapy distilled water (soapy water), air filter cassettes set up with 2.0 L/min. of air flow, and foil-backed patches of underwear cloth with a cover flap of coveralls cloth. The spiking solution was applied to the underwear material and the coveralls patch was then folded down to cover the spiked area. The patch was then exposed to air and sunlight for the duration of the trial in an area upwind from the trial site. The washwater samples for spiking consisted of 50-mL samples of soapy water prepared by putting on latex examination gloves and washing with Ivory soap in deionized water prior to the trial in the same way the operator would wash his hands. 

In the lab, the same primary sample types were used, and samples were also done to verify that the recovery from the coveralls alone was similar to that for the combined underwear plus coveralls patch and to verify that recovery from the individual types of cotton matrix was adequate. The results showed that recovery for the underwear was reduced by the large size of the garment compared to the patches used for the primary field and lab spiked samples. Recovery from the spiked cotton swabs was lower than expected but was still considered adequate (see Table 1). 

Prevalency of screening tests probability that the analyte A is present in a given number of samples Number of primary samples (in sampling) ... 

The relationship between the estimated variances s2 has to consider the number of primary samples, p, subsamples, q, and test samples, q r... 

There are various types of samples within given sampling schemes, e.g., bulk samples > primary samples > gross samples > subsamples > test samples > measuring samples —Fig. 2.4... 

The sampling plan should specify the number and size of primary samples which need to be obtained from the lot/batch. It should also describe how the laboratory sample is to be obtained. These issues may well be outside of the analyst s control, but it is important to consider how the validity of any analysis will be affected. 

Each sector has specific requirements in terms of the number of primary samples that should be taken. Simple empirical rules which have been used in the past to determine the number of samples to be taken from a lot include n = -JN and n = 3 x / N (in each case, N is the total number of items in the lot). In both cases, n is rounded to the nearest integer. 

Other designations for samples are bulk sample, primary sample, secondary sample, subsample, laboratory sample, and test sample. These terms are used when a sample of a bulk system is divided, possibly a number of times, before actually used in an analysis. For example, a water sample from a well... 

Differentiate between bulk sample, primary sample, secondary sample, subsample, laboratory sample, and test sample. 

A bulk sample is the original undivided sample that was taken directly from the bulk system being characterized. A primary sample is the same as a bulk sample. A secondary sample (also subsample) is a part of the primary sample taken to the next step. A laboratory sample is a sample taken to a laboratory for analysis. The laboratory sample could be a primary sample or a subsample. A test sample is that part of a laboratory sample actually measured out for the method used. 

All primary samples were analysed on site using photometric tests... 

The five primary samples per cluster were combined into a single composite sample... 

The focus of process sampling very often is on selecting the final, conveniently small, analytical sample mass as early as possible in the sampling process, preferentially directly as part of the primary sampling. 

Other designations for samples are bulk sample, primary sample, secondary sample, subsample, laboratory sample, and test sample. These terms are used when a sample of a bulk system is divided, possibly a number of times, before actually being used in an analysis. For example, a water sample from a well may be collected in a large bottle (bulk sample or primary sample), from which a smaller sample is acquired by pouring into a vial to be taken into the laboratory (secondary sample, subsample, or laboratory sample), then poured into a beaker (another secondary sample or subsample), before a portion is finally carefully measured into a flask (test sample) and diluted to make the sample solution. 

There are many laboratory devices available for the reduction of the primary sample to an analysis sample. The three most important methods used in the pharmaceutical industry are (i) scoop sampling, (ii) cone and quartering, and (iii) the spinning riffler or rotary sample divider (Fig. A-3). 

In most published methods, the primary sample extracts are subjected to various types of cleanup procedures including conventional liquid-liquid partitioning, solid-phase extraction, matrix solid-phase dispersion, and online trace enrichment. In many cases, some of these procedures are used in combination in order to help obtaining highly purified extracts. 

Using mentioned extraction/deproteinization procedures, the obtained aqueous or organic extracts often represent very dilute solutions of the analyte(s). These extracts may also contain coextractives that, if not efficiently separated prior to analysis of the final extract, will increase the background noise of the detector making it impossible to determine the analyte(s) at the trace residue levels likely to occur in the analyzed samples. Hence, to reduce potential interferences and concentrate the analyte(s), the primary sample extracts are often subjected to some kind of additional sample cleanup such as liquid-liquid partitioning, solid-phase extraction, or online trace enrichment and liquid chromatography. In many instances, more than one of these cleanup procedures may be applied in combination to allow higher purification of the analyte(s). 

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