Field blank defined

Methods for determining the LOD that are based on the analysis of a field blank that does not contain the analyte of interest are problematic in many real-world applications because either such samples do not exist, or would be impossibly difficult to create. As such a circumstance is frequently encountered in environmental analysis, the USEPA adopted a detection limit procedure, termed the method detection limit (MDL), which focuses on an operational definition of detection limit. Specifically, the MDL is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero. The MDL is determined from a replicate analysis of a sample of a specified matrix. Specifically, at least seven aliquots of sample, spiked to contain a concentration of from one to five times the method s estimated MDL, are analyzed. The MDL calculated from these results is statistically tested to determine its reasonableness. If the result fails the testing, this iterative process begins again with a new estimate of the MDL. 

Results of the field QC samples (trip blanks, field duplicates, equipment blanks, etc.) are part of the data packages and, together with field samples, they are evaluated to establish whether they are valid. But what is the significance of these data Like the field samples, these data were collected for a well-defined need, use, and purpose. They provide part of the answer to the question Are the data representative of the sampled matrix ... 

IMAGE stores what is in KK(L) in KA. KK and KA have been defined by the program as double-precision variables. KK must be written with a Hollerith field specification using multiples of 8H. Care must be taken to leave trailing blanks to fill up the eight characters used in the double-precision word. 

For an easy review of characteristic completeness, no blank data fields are acceptable in the database. Accordingly, the Not applicable (N/A) option has been introduced into the PRIS design characteristic system. If particular equipment or parameters that have been defined in the PRIS database do not exist at the NPP, N/A is entered in the related field or text box. This entry will give a user positive information that such a feature is not present at the plant, unlike a blank field, where relevant data may be missing in the database. 

Indexing differentiates between single word- and phrase-indexing. If a field is single word indexed, every single word of this field is searchable. STN calls it single terms. A word is defined as a sequence of alphanumeric characters which are separated from each other by blanks and special characters. Hyphenated words have to be searched as two words ... 

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