Simplify Soil Testing Workflows
Soil analysts often process hundreds of soil samples per day, performing various physical, chemical, and biological tests. The motivation for these tests varies from maximizing yields and profits at the individual level to maintaining food security at a governmental level.
The results, for example, enable farms to identify and replenish only the specific nutrients needed by a given plot of land. Therefore, the data needs to be consistently accurate and reliable.
Working within a high-intensity environment, any strategy to simplify workflows can both relieve pressure on analysts and support data quality, improving lab efficiency and throughput.
Soil assessment
As mentioned, chemical tests on soil provide information on nutrient levels that direct investment and use of fertilizer. These tests might also reveal any contamination from local industrial activity or disposal.
Following protocols and guidelines produced by national and international organizations helps analysts maintain high data quality. These organizations include the US Environmental Protection Agency (EPA) and the Food and Agriculture Organization of the UN.
Bottlenecks in sample preparation
Two key methods for trace metal analysis are flame atomic absorption (FLAA, EPA method 7000B) and inductively coupled plasma atomic emission spectroscopy (ICP-AES, EPA method 6010D). The preparative steps for both of these methods are time-consuming.
In contrast to ICP-AES, FLAA enables analysis of multiple elements simultaneously, which can save some time. However, the inherent heterogeneity of soil demands time-consuming grinding, acid digestion, and filtration (EPA method 3050B) to generate homogenous liquid samples.
When processing potentially hundreds of samples per day, the risk of contamination during these preparative steps is high. Trace elements might transfer from gloves and other samples to the immediate sample or apparatus.
In some cases, the filter paper is itself acid digested to maximize the recovery of certain trace elements, such as lead and nitrogen. Rushing these preparative steps increases the risk of inconsistent and inaccurate results.
Simplifying the workflow
There are alternative analysis techniques, such as X-ray fluorescence spectroscopy (XRF), which require fewer preparative steps. However, comparisons indicate that XRF cannot match the sensitivity of ICP-AES, making the latter the preferred method.
To simplify the workflow, analysts can target the filtration step. Although filtration itself plays a small part in the overall workflow, during peak periods, analysts are likely to hand-fold hundreds of circles of filter paper each day.
A simple switch to pre-folded filters in place of flat circles or sheets effectively negates the manual folding, saving significant time in sample preparation.
An added benefit, on top of improving overall lab efficiency, is reduced paper handling, which also reduces the risk of cross contamination. Taken together, the benefits of this single workflow modification support can improve both data quality and throughput.
Do pre-folded papers comply with standards?
In addition to quantitative ashless grades, Whatman offers a range of Ready-To-Use, pre-folded filter papers made of the same high-quality materials that comply with soil testing standards and protocols.