This depends upon the class of project and reporting requested when initiating the project. Some aspects of Quality Control (QC), for example, blank sample data, are included in all reports (when applicable). Other aspects, such as blank spike data, are not. Please refer to the Chemex Reporting Format page for more information on what is included in a particular reporting package, or contact the Business Development Group or the QA department.
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U stands for Undetected, also commonly referred to as N.D, Not Detected. This means that the target parameter was not detected at the scaled method detection limit (eg, for metals) or the instrument threshold/detection limit (eg, VOC or SVOC). Individual analyses qualifiers are explained in the 'Sample Data and Blank Data' page of the final report. Please click here to learn more about data flagging systems used at Chemex.
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The Method Detection Limit (MDL) is the estimated minimum concentration of analyte in a sample that can be detected with a prescribed level of confidence of distinguishing that sample concentration from the method background signal.

The MDL is the limit at which the laboratory is confident that the analyte can be detected. Continued accurate quantitation at this level is not implied. Greater accuracy (closeness to the true value) and corresponding better precision indicated by a small relative standard deviation (RSD), can be expected at concentrations higher than the mdl where the method is known to produce a linear response. For this reason all Chemex methods will have an established Quantitation Limit.
The MDL should be referred to by data users when considering the significance of a reported low level concentration in a sample.
Please note that dilution factors, percent moisture and other sample specific factors need to be taken into account when establishing QL's for a particular sample.
Click here to read more about how Chemex determine MDL's

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The Quantitation Limit (QL) is the estimated minimum concentration (assuming 100% recovery) of analyte in a sample extract or digest which can, not only be detected, but can also be quantified with an acceptable accuracy. At this limit the measured concentration will be expected to be satisfactorily close to the true concentration. At concentrations above the QL the analytical instrument should be expected to perform linearly. Please note that dilution factors, percent moisture and other sample specific factors need to be taken into account when establishing QL's for a particular sample.
Click here to read more about how we determine the Quantitation Limit.
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Analytical methods are validated statistically using samples that accord to certain ideals in terms of concentration, moisture content etc. Real samples, however, are rarely this perfect. Soils will have an inherent moisture content, water samples may require dilution to bring the level of the compounds of interest to within the instrumental range or a whole host of other factors that may change things from the protocol masses and volumes used to validate the method. All of these factors will combine to produce a single factor by which the sample result will differ from that which would be obtained were all of the conditions as protocol. This factor is called the scaling factor. This scaling factor calculation can be seen here and the effect of the scaling factor on method detection limits is here.
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