SAMPLE COLLECTION

Samples are collected. Along with the Chain of Custody, a Sampling Checklist with any sampling instructions must be included. All of the sampling decisions should have been made at the laboratory in support of the project plan. Ideally, no decisions will be required in the field. Occasionally, unanticipated circumstances may require an alteration of the sampling plan but if possible, this should be done in consultation with the laboratory project manager.

SAMPLE SHIPPING

Samples are returned to the laboratory. Once completed, the samples are repackaged in the shipping containers provided by the laboratory and returned to the laboratory. In an ideal situation, a Field Blank is added to the shipment. This allows for determining if there were any contaminants introduced during the return shipment to the laboratory.

FIELD

The sample kit is shipped to the field. All of the necessary sampling containers must be included. If necessary, preservatives will be added to the containers. The field technicians should only have to open the container, fill the container with sample and seal the container. Chain of Custody documentation must be included.

LABORATORY - SAMPLE KIT SHIPPING

The sample kit is prepared for shipment. When collecting samples in the field, contamination is an issue. The laboratory has to assure that the samples have not been contaminated in the process of sending sample collection containers to the field, as well as, the process of collecting samples and returning the samples to the lab for analysis. This is the purpose of the trip blank and the trip spike. The trip blank, is just that, a sample container filled with a similar sample matrix as the samples to be collected. For example, if the samples are of a contaminated water source, the trip blank sample matrix will be water. The trip blank can also be a well-known, well analyzed sample of the same matrix. The trip spike is a trip blank spiked with a marker compound and a series of compounds which are part of the target analysis collection. That is, if the target analysis is EPA Method 625, then the trip spike would consist of water spiked with a representative number and expected concentration of compounds in the EPA 625 methodology. Depending on the strategy and protocol, multiple trip blanks and trip spikes may be incorporated in the sampling kit. For example, trip spikes at multiple concentration levels may be included to determine the ability to ship and analyze low versus high concentrations of components. Or a range of labile components may be included to determine the stability of the components under the shipping conditions. Both the trip blank and trip spike are packaged such that any tampering with the samples will be evident. And, of course, this is where the Chain of Custody originates.

LABORATORY - SAMPLE KIT RECEIVING

Samples are checked into the lab. Laboratory receiving opens the sample shipping containers to assure that nothing has broken or spilled. This is typically carried out in a closed environment isolated from the laboratory and handled by personnel trained, appropriately equipped and appropriately dressed to address any potentially hazardous conditions. Chain of Custody procedures are observed.

CUSTOMER

The final report is delivered.

SAMPLE RECEIVING

Samples are checked for integrity.Chain of Custody procedures are followed. Samples are checked into the lab. Samples are checked for integrity. Samples are checked for container leaks. Sample seals are checked. Samples are checked against the sample collection list. Where appropriate, samples are checked against the sampling instructions. For example, the size and type of container are checked against the sampling requirements.

Samples have a limited shelf life. Samples must be analyzed before a certain date. That date is determined by the date the samples are taken and the type of analysis to be performed. Sample analysis is scheduled to assure the sample preparation and sample analysis is completed prior to that date. In the cases where sample preparation is not required, sample analysis must be scheduled prior to expiration of the sample integrity.

Samples are stored and staged awaiting preparation or pickup by the appropriate analysis lab. All necessary notices and alerts are distributed. These notices and alerts are checked on a daily basis to assure no irregularities occur.

SAMPLE PREPARATION

Samples are prepared for analysis. Chain of Custody procedures are followed.

Where required, samples are prepared for analysis. The samples are extracted and concentrated to the appropriate volume. They are then transferred to the appropriately labeled containers. During the transfer process an internal standard and the appropriate matrix spikes are added. Laboratory blanks are also processed and added to the sample tray. Laboratory blanks are processed and labeled in an identical manner as other samples. Once in the sample tray, laboratory blanks should be indistinguishable from process samples.

The samples are then recorded and stored. The analysis lab is notified and the samples are placed on the analysis inventory log. Since samples have a specific shelf life, the order in which samples are processed may not follow a strict first in; first analyzed policy. As well, other priorities must be taken into consideration. This makes scheduling samples for analysis a non-trivial task. In some labs, it is a full time job to schedule, track and assure that samples are analyzed and reported in the required time frame and with the appropriate priority.

SAMPLE ANALYSIS

Samples are analyzed. Chain of Custody procedures are followed. Samples are analyzed.

Prior to any sample analysis, the instrument is calibrated over the range which components are to be quantitated. This is typically performed, at least, once a week. If necessary, this instrument calibration process may be performed out of a routine sequence, e.g., after instrument down time. Regardless, at the beginning of each eight hour processing session, a Daily Instrument Calibration is done. This typically consists of one sample which is in the middle of the calibrated quantitation range. In order to qualify as valid, Quality Assurance has predetermined statistical ranges within which the results of these calibration samples must fall. Outside of that range, the samples that are analyzed are not considered valid and cannot be reported.

Depending on the analysis, several internal standards may be added to each sample. Each sample is analyzed in turn. The laboratory analyst does a visual check of the data to be sure the sample was processed properly. That is, the sample was introduced into the instrument correctly and the instrument performed as expected. Quality Assurance has predetermined statistical ranges within which the internal standards must fall. Outside of that range, the samples that are analyzed are not considered valid and cannot be reported.

QUALITY ASSURANCE

Quality Assurance checks for correctness. Chain of Custody procedures are checked and verified.

Quality Assurance checks for correctness. Quality Control is done throughout this process. QA is about verifying that the quality control process worked. Instrument calibration data, internal standards, system blanks and matrix spikes are checked for correctness. That is, this check goes beyond determining if these indicator components are present. It checks to see that the presence or absence of these indicator components make scientific sense. For example, are there trends in the increase or decrease of area counts per internal standard chromatographic peak? Is the absence of matrix spikes due to preparation or analysis issues or is it due to degradation in the matrix? Or is there a pattern in the matrix spike data that would infer shipping issues? Or are there components present across samples belonging to different projects that would suggest cross contamination? Quality Assurance is about looking at the big picture and using the data to determine that all is well.

SAMPLE REPORTING

Sample analysis reports are prepared. The results of individual samples are prepared. Typically, the samples are part of a larger project which requires that summaries and assessments are made. Generally a table of the results of individual samples is included as the reference and centerpiece of the project commentary. In the course of this process component identification is verified and component quantitation is verified. These checks may have been done in the Quality Assurance phase but a double check of these two aspects of the project is always wise. A wrong identification or an incorrect quantitation should be guarded against at all costs.

The project report starts with a Quality Assurance/Quality Control header and synopsis. An assessment of the scientific findings is next and the detailed tables of the sample analysis are last. Following, the flow and format of scientific findings published in peer reviewed scientific journals is not a bad practice.