KIRTLAND AIR FORCE BASE ALBUQUERQUE, NEW MEXICO ...

APPENDIX C
4.1.4 Accuracy
Accuracy is the degree of agreement between an observed value and an accepted reference value.
4.1.4.1 Field Accuracy Objectives
Sampling accuracy will be determined by collecting and analyzing field and trip blank samples, and
adhering to all sample handling, preservation, and shipping requirements. For on-site field test kits and
meters, accuracy will be determined by analysis of calibration standards prior to sample collection.
4.1.4.2 Laboratory Accuracy Objectives
Accuracy is expressed as the percent recovery of standards and matrix spikes. The equation to be used
for accuracy is presented in Section 13.0 of this QAPP. Accuracy control limits will be as specified by
the analytical methods. Standards measure the bias of the analytical system–reagents, equipment,
instrumentation, and analyst technique. Matrix and surrogate spikes measure sample matrix effects as
well as the analytical system bias. In general, calibration and laboratory control standards are used to
monitor and control the analytical system, while matrix spikes are used to screen for matrix effects.
System monitoring compounds (surrogates) will be spiked into all blanks, standards, and environmental
samples (including matrix spike/matrix spike duplicate samples) prior to purging or extraction for
organic sample analysis. Surrogates are compounds that are chemically representative of the method
target compounds. After analysis is performed, surrogate percent recoveries are calculated. These
surrogate percent recoveries will show the efficiency by which the analytical system is measuring known
amounts of different compounds. Surrogate recoveries can, however, be influenced by matrix
interference. Therefore, data for different matrices are compiled by laboratories, and statistically based
limits are established for solid and aqueous matrix percent recoveries.
Method blank analyses also monitor and control the bias of the analytical system by measuring trace
levels of contamination. In general, method blanks containing target analyte(s) at levels greater than the
detection limits trigger the need for corrective action.
Accuracy in the laboratory will be measured by analyzing matrix spikes at a frequency of 1 for every
20 project samples. In addition, quantifiable accuracy will be determined with each batch of samples
prepared and analyzed by the use of laboratory control standards (LCS).
4.1.5 Representativeness
Representativeness expresses the degree to which data accurately and precisely represent a characteristic
of a population, parameter variations at a sampling point, a process condition, or an environmental
condition.
Representativeness in the laboratory is ensured by using the proper analytical procedures and meeting
sample holding times. Analyzing and assessing field duplicated samples will be used to assess
representativeness as well as precision. Sampling networks are designed to provide data representative
of facility conditions. During development of sampling networks, consideration is given to past site
practices, existing analytical data, physical setting and processes, and constraints inherent to the
environmental restoration program. The rationale of sampling networks is discussed in detail in the FSP
(Appendix A of the BWP). Representativeness will be ensured through the implementation of approved,
consistent procedures.
Kirtland AFB
Quality Assurance Project Plan C-21 April 2004