provides quality and efficient integrated laboratory testing services and expertise

Plant sample preparation and submission guide

For Kjeldahl N analysis, macro- and micronutrient analysis by acid digestion and ICP-OES (sample size: < 0.841 mm, < 20 mesh):

Oven-dry samples at 80 °C. Large dried samples are first ground using a stainless steel beater cross grinder and subsampled by quartering to a manageable size. To obtain homogeneous powder, samples are finely ground using the stainless steel cyclone Udy mill or Wiley mill (see Facilities for Rent), and then allowed to pass through a 20-mesh or 0.841-mm stainless steel sieve to avoid metallic contamination. After grinding, the whole sample must be mixed thoroughly.

In between samples, the mill is thoroughly cleaned with a stiff-bristled brush or compressed air. An additional step of sample pre-flushing is recommended before collecting the ground sample for analysis in order to avoid cross-contamination.

For total C, C-13, total N and/or N-15 analysis by Dumas method (< 0.177 mm, < 80 mesh):

Grind oven-dried plant samples to talcum powder fineness (0.177 mm or #80 mesh) using a stainless steel ball mill (see Facilities for Rent).

Place the ground sample in a paper envelope and label it with the following information:

Submit the labeled sample/s with accomplished sample ID list form.

>>> READ MORE... 

Plant Sample Weight Requirement.pdf


ISL's Soil and Plant Processing Facilities are located at the 1st and 3rd floor levels of the Kenzo Hemmi Laboratory. All requests for the use of these facilities must be emailed to at least one week before the date of use. Include the requisition number or a scanned copy of the PR for reference on your email.

Refer to the procedure in using ISL Plant Processing Facilities  and send an email to for any assistance needed.