Western Environmental
Testing Laboratory
Sample Integrity: Sample Collection

Sample Collection is the first, and perhaps the most important step in the analytical process. Poor sampling inhibits the labs ability to produce representative data of a sampling source. Sampling is comprised of 5 main steps:
1. Create a Field Sampling Plan
2. Contact lab to order bottle kit and discuss any scheduling complications
3. Conduct sampling following instructions from Field Sampling Plan and the lab
4. Release Custody of Samples to the lab, or a third party shipper
5. Review Sample Receipt to ensure correct analyses are ordered

What do each of these steps mean? Let’s take a closer look.

1. Field Sampling Plan- This is necessary to succeed in sampling, and generally should include the following:

  • General Facility Info or Sampling Locations
  • Contact Person and Samplers Name
  • Sampling Objectives
  • Facility of Location Information (PWS codes for drinking water)
  • Data Quality objectives
  • Sampling Points
  • Sample Collection Procedure
  • Sample Handling Procedure
  • Equipment Checklist
  • Equipment Preparation and Cleaning Procedures

 

2. Ordering Bottles and Scheduling Sampling- Call us to order your sample containers. The bottles provided will be bagged together into “sets” to keep each site organized. A cooler will also be provided. The lab will generally need the following information:

  • What are you sampling for?
  • How many sites do you intend to sample?
  • When are samples being collected and when will they be delivered to the lab?
  • Are any additional sampling supplies required (COCs, gloves, extra coolers, ice packs, custody seals, Ziploc bags, etc.)?

Depending on the situation, more coordinating and information may be required! For example:

Courier Pick Up or Drop Off– If you need sample containers dropped off at your site or picked up from a courier, it is wise to plan sampling around your labs standard courier routes. You can find WETLAB’s standard courier schedule here.

Sample Shipping– If samples are being shipped to or from a remote location, consider the amount of time samples will be in transit. If you are sending short-hold samples, selecting a “next day delivery” option may be necessary.

Subcontracted Work– Most subcontracting is shipped to southern CA and NV, therefore, factor this extra time in transit when making your sample plan. Furthermore, avoid delivering samples requiring subcontracting on Fridays, as they cannot ship out until the following Monday.

Weekend Work– Weekend work is not ideal, however, it is sometimes unavoidable! It is important, however, to notify your lab as soon as possible about weekend work so that staff can be scheduled to accommodate the request.

 

3. Sampling- Once the game plan is set, it is time to execute your sampling project.

  • Follow the steps outlined in your Sampling Plan and make sure to follow any special instructions provided by your lab.
  • Take note of the weather conditions, high and low temperatures can drastically affect how you pack and transport your samples.
  • Wear PPE! Gloves, glasses, masks, hairnets… they all serve a purpose to keep you safe and/or your samples clean.
  • Make sure to add the proper preservatives to your samples in the field, add custody seals to bottles or coolers if your sample plan requires them, and make sure to use bubble packaging for glass containers.

 

4. Releasing Custody of Samples- An additional responsibility of a sampler is properly documenting sample information and signing for any change of sample custody. The analytical Chain of Custody (or COC) is a required legal document submitted with samples to the laboratory. This document is a requirement for any sample submission to a lab, and serves numerous purposes:

  • Client and Reporting information
  • Turnaround time, compliance needs for reporting, report format, and QC requirements
  • Sample ID, Date/Time, Preservatives, Matrix, Number of Containers, and required tests
  • Miscellaneous comments, including hazard warnings, reporting requests, sample return requests, preservative notes, etc.
  • Relinquishing custody of the samples

 

5. Review Sample Receipt- WETLAB can send you an electronic “ sample receipt” which will list the entered information from your Chain of Custody, the receiving conditions of your samples (including anomalies), and an itemized list of all the analytical testing slated for your samples.
This is the final check before the testing will commence, so it’s important to review as soon as possible and contact the lab with any questions or concerns.

Contact WETLAB at (775)355-0202 to discuss your sampling requirements and project needs.

Organic compounds are present in both indoor and outdoor environments, as they are necessary ingredients of products and materials we use every day.  Semi Volatile Organic Compounds (SVOC) are a subgroup of Volatile Organic Compounds (VOC) that have a higher molecular weight and boiling point (240-260 C to 380-400 C) and are present in everyday items like pesticides and fire retardants.

SVOCs are analyzed by sample extraction and the extract is analyzed by Gas Chromatography/ Mass Spectrometry (GC/MS).  The reported analytics can be separated into three groups (acids, bases, and neutrals) and are sometimes referred to as Base/Neutrals and Acids. WETLAB is currently in method development to perform the analysis of municipal and industrial wastewater by EPA 265 and solid waste, soils, and waste samples by EPA 8270.

At WETLAB, we are constantly trying new ideas, methods, and analyses to better serve our clients.  Contact us at (775) 355-0202 to find out how our new, in-house SVOC analysis can help you get the environmental testing results you need.

In our blog posts Lessons From the Lab we answer frequently asked questions from clients.  Find all installments of Lessons From the Lab here

What is a Reporting Limit?

A Reporting Limit (RL) is defined as the smallest concentration of a chemical that can be reported by a laboratory. If a laboratory is unable to detect a chemical in a sample, it does not necessarily mean that the chemical is absent from the sample altogether. It could be that the chemical concentration in the sample is below the sensitivity of the testing instrument. Concentrations below the RL are reported as not detectable at the RL or “less than” the RL. The RL value is often defined be each specific laboratory, so it is not uncommon to come across different RL’s when testing the same compound. RL’s act as safety protocols that allow laboratories to efficiently communicate the different variables correlated with testing and analyzing samples from a wide variety of sources and factors. It is important to identify the limit of concern that the client has when testing their sample to ensure that the RL is less than the regulatory limit. That enables a laboratory to identify whether a concentration of the chemical in question is above the regulatory limit of concern.

The Method Detection Limit (MDL) is defined as “the minimum concentration of a substance that can be measured and reported with a 99% confidence that the analyte concentration is greater than zero” (40CFR sec. 136 Appendix B). The MDL is used for various reasons in an analytical laboratory, with the primary reason being it is used to determine the reporting limits for each analyte that a laboratory analyzes for. Reporting Limits (RL’s) are generally 3-5 times the MDL. On occasion a laboratory can report lower than the calculated MDL, however these results are always flagged as estimates and cannot not always be considered legally defensible data. MDL studies are also required as part of the process of maintaining certifications.

A MDL is initially established when a method is set up, a new piece of equipment is brought online or if there is a significant change in equipment or location (i.e. moving to a new location, significant maintenance or replacement of major parts). MDL’s are confirmed on a regular basis according to method specifications (generally on an annual basis but for some parameters, such as anions, it is done twice a year). MDL studies are performed on a regular basis to assure that there is no loss of sensitivity on the equipment due to wear and tear or the constantly changing environmental conditions.

Do you have more questions about MDL’s or questions about other laboratory terminology? Is there something that always confused you about laboratory services? Leave a comment and let us know what you want to know about!