Standard methods call for fresh GGA standards every (batch, day, week), which takes hours of your valuable time each week. In addition, it's challenging to achieve consistent results with in-house preparation of GGA standards, causing inconsistent results. Here's how we fix that, and how you can save dozens of hours this month.
Here’s some food for thought.
Standards aren’t always as standard as you hope.
Making GGA standards in-house is time and budget-consuming. It takes about 2.5 hours:
But if you work with a provider other than CPI for your GGA standards, you might run into a problem like this municipal utility:
The utility was having difficulty obtaining accurate and precise glucose-glutamic acid (GGA) results for daily biochemical oxygen demand (BOD) testing of a municipal wastewater effluent.
Test results would be within specification (198 mg/L +/- 30), but when the facility ordered GGA standards with a new lot number from their vendor, it would take multiple reorders before finding a new lot number that gave acceptable results.
That’s a huge waste of time, budget, and mental focus.
So our team set out to create a more accurate and precise procedure for GGA standards. Giving our customers access to:
- Massive time savings that come from prepared GGA standards and…
- Even greater quality than in-house fresh standards produce.
How to get more accurate and consistent GGA standards
Here’s what our team did.
- Took a deep dive on published information regarding the relationship among BOD, total organic carbon (TOC), and COD. The literature indicates a BOD:COD:TOC relationship for a particular sample.
- Derived the BOD, COD, and TOC factors from a sample. And using these factors as a backbone, created a lot volume of 20 L.
- WAIT! Why 20 L?
- When you only make up 1 L, which is what most labs do, you have to measure out 150 mg of each reagent. Weighing out milligram amounts can be tricky, and humidity can be a factor. Weighing 3.00 g of reagent for a 20 L lot is much easier.
- Inadvertent microbiological activity could compromise concentration of the standard. So, autoclaving was employed to eliminate the possibility.
- This was separated into 6-mL vials of individual, sterile material.
- WAIT! Why not larger?
- Because larger vessels might be sterile initially, but once opened and used, sterility could be compromised.
Then the team took a little break to build a custom, automated liquid handling system dedicated to GGA production. It’s called a gantry. And it uses fluid-metering pumps with ceramic pistons known for their chemical resistance and long-term, precise performance.
The standard operating procedure developed describes the use of low conductivity, reverse-osmosis deionized water (<0.1 μmhos/cm) even though Standard Methods for the Examination of Water and Wastewater allows a much higher level (sometimes you’re allowed to drive 70MPH, but going around that sharp corner you’re a lot safer if you err on the side of caution, right?)
So the 20-L tank is filled to 18 L, the 2-L volumetric flask of dissolved glucose and glutamic acid are then added, bringing the total volume to 20 L.
If an unautoclaved aliquot meets specifications at this point, production commences.
How does production differ from what I do in my lab?
First, making GGA standards in your lab takes a lot of time and you only get a small volume. Since Standard Methods calls for creating this fresh every time, you might be wasting dozens of hours every month preparing it.
So instead of using your ovens and dessicators and analytical balances and flasks and boats and refrigerator, you could just grab a vial and start the workflow.
What happens when we produce your GGA standards?:
- Boxes of 250 glass culture tubes are placed in the gantry and filled with 6 mL of reagent.
- The tubes are capped and autoclaved.
- After the first batch is done, it’s tested for:
- heterotrophic plate count (HPC)
- COD
- TOC.
- *Standard Methods acceptance criteria, 198 +/- 30 mg/L
- If the HPC results are 0 CFU/mL, and TOC and COD are within specification, the batch is approved.
- A box of 150 filled tubes are sealed in a plastic sleeve, inverted, vacuumed to determine if there are any leaks.
- No leaks? They’re sent out to you.
They’re shelf stable for at least 4 years (that’s as long as we’ve tested, since it seems adequate for any scenario we can imagine).
So instead of making fresh GGA standards every time you need them, you place a single order every few years and simply open a tube.
Potentially saving hundreds of hours every year.
Want to place your first order? Follow the link below.