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Quality Assurance / Quality Control

Aquatech Enviroscience Laboratories Inc. is proud to have a team of well trained and highly experienced analytical chemists. A comprehensive Quality Assurance / Quality Control (QA/QC) program has been developed and followed for all sampled analyzed at our laboratory. We are committed to providing the highest quality data possible.

QA/QC Procedures
The basis of our QA/QC plan is the batch method. Each batch of samples (with accompanying QC samples) goes from sample work up through instrumentation and on to data interpretation and final reports as a unit. The QA/QC data are evaluated to assess the quality of each sample batch. Certain criteria must be satisfied before sample data are reviewed.

  • Sample batch – Each batch consists of a maximum of nine samples, plus three QA/QC samples: reference material or spiked sample, a duplicate sample, and a procedural blank.
  • Reference Material – Standard or certified reference material are routinely analyzed where they are available. For analyses where no certified materials are available, spiked samples are used to assess the accuracy of the data. For data acceptance, results must be within specified limits.
  • Duplicates – Results for duplicates are presented along with the analysis results. One sample in each batch is analyzed in duplicate at no extra cost to the client. Duplicate results must agree to within limits specified for each analysis.
  • Blanks – One procedural blank is analyzed with each batch of samples to ensure the absence of interferences.
  • Surrogate Standards – Chemically labeled analogues of the target compound are added to each sample prior to sample work up for evaluation and correction of the recoveries of the target analytes.
  • Recovery Standards – Additional labeled analogues are added to each extract after sample work up and prior to instrumental analysis for determination of surrogate standard recoveries.

Instrument Analysis
Instrumental QA/QC procedures are implemented prior to analysis and on an ongoing basis.

  • Instrumental Linearity Verification – Instrumental linearity is routinely determined by a multi-point calibration. The Relative Response Factors (RRFs) for the linearity set must agree to within 15-20%, depending on protocol.
  • Daily Calibration – Mass Spectrometers are tuned and mass calibrated on an ongoing basis. RRFs are determined by a single point calibration prior to analysis of each batch of samples, bracketing if necessary sets of samples. RRFs at the beginning and end of each sample bracket (12 runs) must agree to within 10% and to within 15% of the linearity verification.
  • Sample Carryover – The absence of sample carryover from previous injections is assured by running a solvent after every calibration standard. In addition, sample data is scrupulously monitored to ensure that carryover of a proceeding sample has not occurred.
  • Window Standard – A standard check is run before analysis of each batch of samples to define the retention time window during which a group of compounds is expected.

Data Evaluation

  • When sample batch and instrumental QA/QC criteria are satisfied, sample data are evaluated for chromatographic quality, ion ratios, retention times and linear range.
  • Recoveries of the labeled surrogate compounds (added as internal standards) are required to be in an acceptable range, which is defined for each analysis, but is generally 40-120%.
  • Detection limits are reported for each sample and are calculated as the concentration equivalent to the minimum detectable instrument response. This is determined from the mass chromatogram of the compound and is defined as a peak of height three times the maximum height of the noise.

Aquatech Enviroscience Laboratories Inc. stands by its high quality data. The company’s reputation is a pure result of a combination our chemist’s expertise, meticulous methodologies, state-of-the-art instrumentation and uncompromising sophisticated QA/QC program.


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