The EPA does not approve specific equipment. They state that alternative technologies can be used if you can demonstrate equivalency, or better, performance. What matters is proving that the method produces the same or better results. 

In Canada, for example, and in the US, national accreditation bodies accredit to ISO/IEC 17025. So, you simply must validate your method in-house according to ISO/IEC 17025 requirements. 

Regulators and accrediting bodies care that your method is scientifically defensible, reproducible, and traceable to CRMs and quality control standards. The results we presented today suggest that the ColdBlock soil method can meet this criteria, but each laboratory must validate the method in-house to demonstrate it as a valid alternative to 3050b.

The EPA does not approve specific equipment. It states that alternative technologies can be used if you can demonstrate equivalent or superior performance. What matters is proving that the method produces the same or better results.

In both Canada and the U.S., national accreditation bodies accredit laboratories to ISO/IEC 17025. Therefore, you simply need to validate your method in-house according to ISO/IEC 17025 requirements.

Regulators and accrediting bodies care that your method is scientifically defensible, reproducible, and traceable to CRMs and quality control standards. The results we presented today suggest that the ColdBlock soil method can meet these criteria; however, each laboratory must validate the method in-house to demonstrate it as a valid alternative to 3050B.

3050B is designed for metals that are stable during heating in nitric and hydrochloric acids. Traditionally the method is done in open vessels like heating blocks or heating plates. 

Mercury behaves differently than most metals and volatility is an issue. When heated in nitric or hydrochloric acid, Hg(II) forms species like elemental mercury or volatile chlorides that are highly volatile and can escape into the air. That’s exactly what happens in an open heating block or hotplate setup as there’s no mechanism to keep vapors in solution. 

This makes recoveries inconsistent and unreliable, which is why 3050B explicitly says it is not suitable for mercury. Mercury has its own EPA method (7471B) so labs can use conditions tailored to its chemistry. This avoids poor data quality from a one-size-fits-all approach. 

ColdBlock overcomes this issue with its cooling block, which condenses vapors back into the solution. Volaltile elements like mercury do not escape into the air. Even if Hg(II) reduces to Hg(0) during digestion, it’s reabsorbed into the solution instead of being lost. This is why you can confidently include mercury and show strong recoveries using ColdBlock.

Yes, in samples with higher organic content, we see improved recoveries of elements that are often bound in organic complexes. This is because we have standardized the addition of peroxide ensuring consistent oxidation of the organics across all sample types.

There are consistent recoveries of antimony, arsenic, lead, and occasionally cadmium, and the data suggest that the ColdBlock method reliably liberates metals sequestered in complex organic matter, improving overall extraction efficiency.

The entire ColdBlock digestion system has been designed for scalability.

For the soil digestion method presented here, the ColdBlock Pro Series CBM was used. It has 16 channels, so a single digester can run up to 16 samples at a time. 16 samples are digested in 45 minutes. The system is scalable in that multiple digesters can be connected to the same controller. As they can all be loaded so that the same time, two medium ColdBlock digesters would mean 32 samples can be run at once. That’s 32 samples every 45 minutes.

We are often asked the question about throughput capacity and what improvements can be achieved when switching to ColdBlock. With ColdBlock’s short cycle time, and a similar capacity to other technology such as heating blocks, the outcome is a 4X increase in throughput capacity by simply scaling up to a double digester.

ColdBlock has been built in a way to allow a simplified installation and maintenance process. In terms of installation, it is a very straightforward process, and a simple transition from heating blocks or microwave. It runs in a vent hood, and has similar ventilation and power requirements. However, the main difference is that ColdBlock uses a chiller for the cooling zone.

Maintenance takes less than 10 minutes per week, and involves a visual inspection of the unit, and a wipe down of the inside of the unit (if required). It is a very simple process that doesn’t require replacement or consumable parts. Maintenance can be done in your own lab by a lab technician, and it does not require outside maintenance or recalibration of any kind.

Please review the installation and maintenance video for more insight into the process.

After the digestion, the samples are diluted appropriately. We run instrument checks to minimize matrix effects on the instruments. Our digestions are producing solutions with a higher chloride content than typical 3050B digestions.

For ICP-MS, we manage this using our collision cell with helium in kinetic energy discrimination mode. This reduces polyatomic interferences. We also use internal standards to correct for any residual signal suppressions on the machines.

For OES, we’re monitoring wavelengths carefully, and we’re applying background correction to avoid spectral overlaps.

Overall, the ColdBlock method pairs very well with current ICP and ICP-MS instruments.