Batch sampling

Colorants. According to U.S. regulations, colorants are divided into two classes certified and exempt (see Colorants for foods, drugs, COSMETICS, AND MEDICAL DEVICES). Batch samples of certified colors must be sent to the FDA for analysis and confirmation that the colorants comply with estabhshed specifications. Color manufacturers pay a small fee for each batch of color that is analy2ed. The number of certified colors available to food technologists has declined. Several of the historical colorants were found to have carcinogenic effects. Table 1 shows the certified colors that are permissible for food use in the United States as of 1993. 

In the CIELAB and CIELUV color spaces, the difference between a batch sample and a reference standard designated with a subscript s, can be designated by its components, eg, AAL = L — L. The three-dimensional total color differences are given by EucHdian geometry as the 1976 CIE lYa b and 1976 CIE lYu Y color difference formulas ... 

Are all production batches sampled for Quality Assurance approval ... 

Another significant difference between large- and small-scale processing is dilution of the product samples with water. Food processing equipment for fluids often needs to be started with water, and the food needs to be flushed from the system with water before the process is shut down. When making small batch samples in this type of equipment, care must be taken to obtain a representative sample with a minimum of dilution. There will also be a difference in the weights of the sample into and out of the process due to water addition or sample loss to minimize dilution. 

Fraction of a lot (batch sample) taken Gy [1992] without respecting the rules for sampling correctness or under unknown conditions. 

Stability — Samples remain stable for at least 468 days when frozen at -20°C. They are stable for at least five simulated freeze-and-thaw cycles and approximately 28 hr at room temperature. The analyte is viable for at least 6 days in a reconstitution solution stored in the autosampler (temperature set point at 10°C). A dried-down batch (sample process stopped at dry-down step) was stable at least 5 days in a refrigerator (temperature varied from 4 to 8°C). A stock solution of paricalcitol is stable for at least 11 months. Stock solution of internal standard is stable about 4.5 months under refrigeration. 

Evolved gases were monitored continuously for 02, C02, NOx, CO, and total hydrocarbons (THC) by a continuous emission monitoring system (CEMS). Batch samples of the offgases were also taken and analyzed for NH3, HCN, residual energetic materials, volatile organic compounds, and N2. The batch samples were collected over the entire duration of each run, and the single value reported represents the average concentration for the whole run. 

The selectivity is demonstrated by analysis of a mixture of the relevant compounds, e.g., a selectivity batch/sample solution. The resulting electropherogram is compared with the selectivity electropherogram provided in the method description. The resolution between the critical peak pair(s) is determined. The target resolution should be >2.0 (the calculation... 

The imperative is always to respect that all extractions (all possible virtual increments) must have the same selection probability. This is called the fundamental sampling principle (ESP), which must never be compromised lest all possibilities of documenting accuracy (unbiasedness) of the sampling process are lost. ESP implies potential physical access to all geometrical units of the lot, which is easily seen as much easier to achieve in the process situation than in batch sampling cases. The TOS contains many practical guidelines of how to achieve compliance with ESP [1-14], as praxis-codified in the seven sampling unit operations outlined below. 

Figure 3.7 Sampling error relationships for the case of batch sampling (0-D). A core of correct sampling errors (CSE) is embedded in a cloak of incorrect sampling errors (ISE). Representative sampling must start by eliminating all ISE.

The fundamental principles for representative sampling and effective counteractions towards heterogeneity were delineated for batch sampling (0-D) as well as process sampling (1-D). All principles are contained in the theory of sampling (TOS). 

After mixing, the propellant is transferred into a casting pot, a container in which it may be held and from which it may be cast. The long pot life of mixed PVC plastisol propellant permits it to be held almost indefinitely to meet the convenience of the production schedule. The long pot life also makes possible the full characterization of a batch of mixed propellant, by extensive tests on batch samples, before the batch is committed to further processing. 

The alternative approach is to prepare a composite sample from the individual batch samples and from that take a sample for finished excipient release testing. This approach requires combining equivalent quantities from the individual batch samples into a container. Once all of the material has been added from the individual samples, the composite sample must be blended to make it homogeneous. Once the composite has been adequately blended, a representative sample must be taken for finished excipient testing. These test results are then reported on the COA. 

Unlike other spectroscopic methods requiring samples under vacuum or very low gas pressures, NMR spectroscopy of working catalysts is not limited by the so-called pressure gap. The flow techniques described in Section III.B are suitable for catalytic reaction experiments under atmospheric pressure. If necessary, a higher pressure inside the MAS NMR rotor reactor can be used. The gas pressure inside batch samples may be limited by the strength of the walls of the glass inserts or the type of the cap used to seal the MAS NMR rotor after the preparation of the reaction system. In both cases, at least atmospheric pressure can be reached inside the sample volume. 

Sampling. Composite or continuous sampling furnishes water samples that are more representative than grab or batch samples. If possible, such samples should be used and processed immediately to avoid storage problems. However, the collection of small-volume samples may be more easily accomplished by batch sampling. 

The following section is a review of instruments and techniques that have been used and/or specifically developed for aircraft measurement of trace species. To limit the scope, focus is restricted to species that we have identified to be of interest to a large segment of the atmospheric chemical community. The objective is to give the reader a starting point from which to either choose or develop an instrument or technique for aircraft sampling. This section is divided into two parts the first covers techniques that are used for batch sampling or analysis of atmospheric constituents the second is a review of continuous analysis methods. 

Chromatographic Techniques. These techniques have long been applied to the problems of separation and analysis of trace atmospheric species. For stable species, batch samples are usually collected as described in the preceding section and transported to the laboratory for subsequent analysis. However, some compounds are not sufficiently stable to survive transport intact. In situ chromatographic analyses have been used for these samples. Usually, chromatography is used on aircraft in a batch mode samples are collected, preconcentrated, and separated on a column, and the individual species are detected as they elute the process is then repeated for the next sample. Thus, as with other batch techniques, time resolution is limited. 

With few exceptions, the results given by fluorometry, chromatography and neutron activation analysis compare well with those obtained by inductively coupled plasma atomic emission spectrometry. The precisions obtained for the various samples were very good for between- and within-batch samples. 

Accuracy determines the closeness of the analytical data to the true value. It is estimated from the recovery of a known standard spiked into the sample. Based on the percent spike recovery, a correction for the bias may be made. Routine environmental analyses generally do not require such corrections in the results. However in specific types of analysis, correction for bias may be required when the percent spike recovery for a QC batch sample is greater than 0 and less than 100. In the wastewater analyses for certain organics, U S. EPA has set forth the range for percent recovery. If the spike recovery for any analyte falls outside the range, the QC criteria for that analyte is not met. 

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