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Particle Size Distribution (Rotap) Test

  • Up to 6 sieves: 70 per analysis
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  • 7-9 business days
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  • Rush Available
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Particle Size Distribution (Rotap) Test

Technical data sheet


Method description

Up to six sieves can be stacked on the Rotap in descending size order. The sample is placed on the top sieve and is sifted down via the shaking and tapping action of the instrument. Sample weights retained on the sieves are recorded. A full range of sieves with openings from 1 inch to 0.037 mm are available.

Acceptable matrices

Free-flowing powders and particulates

Unacceptable matrices

Liquids, particle sizes that are >25 mm



Method reference

Internally-developed method

Reportable unit

% retained on each sieve

Sample size requirements

100 grams

Information required by submitter

We need to know the sieve sizes to be tested, either US Std. sieve numbers or particle size range to be covered (micrometers, millimeters, or inches). The use of flow agents or run times can be specified to meet method requirements.

Additional information

This method sizes particulate samples and powders by sieve separation. However, for sticky or high-fat samples, the Alpine tester is more accurate.

Rotap Sieve Sizes
Sieve# Opening(“)  Opening(µm)
1-inch  1.000
3/4-inch  0.750
 5/8-inch  0.625
 1/2-inch  0.500
 7/16-inch  0.438
 3/8-inch  0.375
 1/4-inch 0.250
 #4  0.187  4750
 #5  0.157  4000
 #6  0.132  3350
 #7  0.111  2800
 #8  0.0937  2360
 #10  0.0787  2000
 #12  0.0661  1680
 #14  0.0555  1410
 #16  0.0469  1190
 #18  0.0394  1000
 #20  0.0331  840
 #25  0.0280  710
 #30  0.0232  590
 #35  0.0197  500
 #40  0.0165  420
 #45  0.0138  350
 #50  0.0117  297
 #60  0.0098  250
 #70  0.0083  210
 #80  0.0070  177
 #100  0.0059  149
 #120  0.0049  120
 #140  0.0041  105
 #170  0.0035   88
 #200  0.0029   74
 #230  0.0024  62
 #270  0.0021  53
 #325  0.0017  44
 #400  0.0014  37
*Prices and offerings are subject to change without notice.

Common Particle Size Distribution (Rotap) Test Testing Questions

While our sales and customer service team are happy to answer general testing questions, consultations typically start at a rate of $250 per 30 minutes regarding the interpretation of reported test results or questions about our test methods. We cannot consult on regulations, tolerance limits, or claims.

We make every effort to keep our methods and detection limits up to date according to the latest standards and qualifications. If you have any questions regarding the limit of detection/quantification or method references, please contact our Customer Service team at 1-800-245-5615.

Our standard turnaround time is 10 business days for most assays. There are some assays that require a longer turnaround time. We also offer a RUSH service that is half the time of the standard turnaround time of the assay at double the cost of the assay. A few assays that we provide cannot be rushed due to the nature of the test. Please check the specific assay you are interested in regarding the ability to RUSH the turnaround time.

Medallion Labs, a division of General Mills, offers multiple areas of expertise for analytical testing and product evaluation for the food and ingredient industry. Our areas of expertise include Chemical Analysis, Nutritional Analysis, Food Safety, Shelf Life Studies, Microbiology, Specialty Fibers, Physical Testing, Allergen Testing, as well as Product Evaluation (which includes Product Performance and Sensory Evaluation) and Technical Consulting/Method Development. Our methods are developed for the testing of food products and ingredients.

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Medallion Labs

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