NCTR Particle Size SOP.pdf

Uncontrolled when Printed SOP No. NCTR OSC CHEM 316.03, Page 1 of 2

National Center for Toxicological Research Division of Biochemical Toxicology

Chemistry Support Group US Food and Drug Administration, Jefferson, AR

Laboratory Operating Procedures SOP No: NCTR OSC CHEM 316.03

Prepared by: F. McLellen

Approved by OSC/Chemistry Team Leader:

Supersedes: 316.02 Date Approved Page 1 of 2 Effective Date: 00/00/00

Standard Operating Procedure Particle Size Analysis of Harwood Chips

1. PURPOSE:

This procedure is to describe the standard operating procedure (SOP) for analysis of particle size of hardwood chips in compliance with FDA Good Laboratory Practice (GLP) as specified by 21 CFR 58.

2. SCOPE:

This procedure applies to the determination of particle size of hardwood chips utilized at the

NCTR.

3. PRINCIPLE

A sieve shaker is used to shake two sieves of different sizes, and a receiver pan in order to determine the particle size of hardwood chips.

4. MATERIALS and SUPPLIES

a. Balance with accuracy to 0.01g

b. U.S. Standard #8 Sieve: 2.36 micron/0.093 inches

c. U.S. Standard #20 Sieve: 850 micron/0.0331 inches

d. Receiver Pan

e. Ro-Tap sieve shaker (I.E. Ro-Tap RX-812)

f. Scoop

5. Procedures

Note: Prior to weighing operations, the analytical balance is calibrated, and the calibration is documented with NIST traceable weights in the weight range of the intended operation.

A. Weigh each clean, empty sieve pan and record each empty weight.

B. Nest the sieve pans in the following order: #8 on top, #20 in the middle, and receiver pan on bottom. Place the nested sieve pans and receiver pan on the balance.

C. Tare the balance and weigh 25.00g into the #8 (top) sieve pan. Record this weight as the total sample weight.

D. Place the nested sieve pans and receiver pan on the Ro-Tap sieve shaker.

E. Using the Ro-Tap sieve shaker, shake sieves for 3.0 minutes.

F. Stop Ro-Tap sieve shaker and remove sieve pans and receiver pan from the Ro- Tap sieve shaker. .

G. Carefully separate the sieve pans and receiver pan from each other. Be careful not to spill the contents of any of the pans.

Uncontrolled when Printed SOP No. NCTR OSC CHEM 316.03, Page 2 of 2

H. Weigh each pan, to 0.01g, separately on a tared balance. Record each weight as the (sample weight+ pan weight) for that pan.

5. Calculations

Sample Weight after shaking= (Sample Weight + Pan Weight)- Pan Weight

Example: 25.00g of sample were placed in the #8 sieve. The nested sieves were then placed on the Ro-Tap sieve shaker and allowed to vibrate for 3.0 minutes. The results are listed.

Pan Pan Weight Sample Weight+ Pan Weight

Sample Weight after shaking.

#8 Sieve 300.00 301.72 1.72

#20 Sieve 300.00 323.01 23.01 Receiver Pan 300.00 300.29 0.29

% Retained = Sample wt after shaking x4 (1.72 x4 = 6.88 %)

7. Particle Size Limits (Updated 2025)

#8 Sieve – no more than 10% of the original sample weight.

Receiver Pan – no more than 0.7% of the original sample weight.