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Volume IV - 5.6 Sample Analysis

DFS Pyramid Logo

Orientation and Training

Food and Drug Administration

DOCUMENT NO.:

IV-05
VERSION NO.: 1.3

Section 5 - Pesticides Analysis

EFFECTIVE DATE: 10/01/2003REVISED: 02/14/2013

5.6.1  Sensitivity Levels for Pesticide Residue Determination

A.  Objective

To acquaint the trainee with the approximate sensitivity levels in multiresidue analysis.

B. Assignment

Read the reference and become familiar with its contents.

C.  Reference

  1. U.S. Food & Drug Administration, Center for Food Safety and Applied Nutrition, Office of Plant, Dairy Foods and Beverages. Makovi, C. M. (Ed.), McMahon, B. M. (Ed. Emerita). (1994). Pesticide analytical manual-multiresidue methods (3rd ed., Vol. I, section 105-Analytical Limits of Quantitation, updated October 1999). R.O.W. Sciences, Inc.

D.  Questions

  1. What criteria are required before considering a peak of 10% FSD as a trace or non-significant peak?
  2. What is the identity and quantity of each pesticide injected in establishing detector response for chlorinated, organophosphorus, and early-eluting residue determinations?
  3. For an organophosphorus compound, what is the trace level (ng) that gives 75% FSD for 7.5 ng, assuming correct setup?

5.6.2  Sample Preparation and Compositing

A.  Objective

To familiarize the trainee with PAM methods for sample preparation and compositing.

B.  Assignment

The trainer will explain how to prepare the following samples and how to select a representative portion to be held by the laboratory:

  • A case of apples and a case of peaches
  • Smelt sample consisting of 20 fish, less than 2 lb total
  • Salmon sample of 20 fish, about 5 lb each
  • Milk concentrate and low-fat dairy product
  • Coarse dry animal feed n 20 lb of bananas

As assigned, prepare samples for laboratory analysis.

C.  References

  1. U.S. Food & Drug Administration, Center for Food Safety and Applied Nutrition, Office of Plant, Dairy Foods and Beverages. Makovi, C. M. (Ed.), McMahon, B. M. (Ed. Emerita). (1994).Pesticide Analytical Manual-multiresidue methods (3rd ed., Vol. I, section 102-Preparation of Analytical Samples, updated October 1999). R.O.W. Sciences, Inc.
  2. U.S. Food & Drug Administration, Office of Regulatory Affairs, (current edition). Investigations operations manual (IOM) (chap. 4, Sample Schedule Chart 3 for Pesticides, pp. 196-199).

D. Questions

  1. How would one prepare a sample of 20 melons submitted to the laboratory?
  2. How would one prepare a sample of six l-gallon cartons of milk?
  3. How would one prepare a sample of 20 lb of wheat?
  4. How would one prepare a sample of slightly decomposed heads of lettuce? Very decomposed heads of lettuce?
  5. What are the major considerations for a laboratory sample in regard to the sample received by the laboratory and storage of reserve portions?

5.6.3  Nonfatty Foods-Multiresidue Determination

A. Objective

To acquaint the trainee with methods used to prepare, extract, and clean up samples of nonfatty foods for analysis of organochlorine and organophosphorus residues.

B.  Assignment

  1. Under the observation of an experienced analyst, prepare, extract, and clean up routine samples, including a fortified (spiked) sample and a reagent blank. The fortified sample should contain a chlorinated and an organophosphorus compound.
  2. Store all sample extracts for GC determination until completion of the next section on fatty foods.

C.  Reference

  1. U.S. Food & Drug Administration, Center for Food Safety and Applied Nutrition, Office of Plant, Dairy Foods and Beverages. Makovi, C. M. (Ed.), McMahon, B. M. (Ed. Emerita). (1994). Pesticide analytical manual-multiresidue methods (3rd ed., Vol. I, sections 302-Mehtod I for Nonfatty Foods and 303-Method II for nonfatty Foods, updated October 1999). R.O.W. Sciences, Inc.

D.  Questions and Instructions

  1. Briefly describe the extraction and cleanup principles involved in this assignment.
  2. What three types of samples call for the following blending techniques: acetonitrile, 35% water-acetonitrile, heated acetonitrile-additional water?
  3. What extraction procedure would be recommended to obtain complete extraction?
  4. Where are the sample extracts from assignment (2), above, stored?

5.6.4  Fatty Foods-Multiresidue Determination

A.  Objective

To acquaint the trainee with methods used to prepare, extract, and clean up samples of fatty foods for analysis of organochlorine and organophosphorus residue compounds.

B.  Assignment

Under the observation of an experienced analyst, prepare, extract, and clean up several routine samples, a reagent blank, and a fortified sample (milk or cheese is suggested).

C.  Reference

  1. U.S. Food & Drug Administration, Center for Food Safety and Applied Nutrition, Office of Plant, Dairy Foods and Beverages. Makovi, C. M. (Ed.), McMahon, B. M. (Ed. Emerita). (1994). Pesticide analytical manual-multiresidue methods (3rd ed., Vol. I, section 304-Method for Fatty Foods, updated October 1999). R.O.W. Sciences, Inc.

D.  Questions

  1. Briefly describe the extraction and cleanup principles involved in the assignment.