<PAGE>
                                                                    Exhibit 10.4

                                FIFTH AMENDMENT
                           DATED AS OF MARCH 26, 2003
                                       TO
                           RECEIVABLES SALE AGREEMENT
                         DATED AS OF DECEMBER 21, 2001

     THIS FIFTH AMENDMENT (the "Amendment"), dated as of March 26, 2003, is
entered into among PerkinElmer Receivables Company, as Seller (the "Seller"),
PerkinElmer, Inc., as Initial Collection Agent (the "Initial Collection Agent,"
and together with any successor thereto, the "Collection Agents"), the committed
purchasers party thereto (the "Committed Purchasers"), Windmill Funding
Corporation ("Windmill"), and ABN AMRO Bank N.V., as agent for the Purchasers
(the "Agent").

                                  WITNESSETH:

     WHEREAS, the Seller, the Initial Collection Agent, the Agent, the Committed
Purchasers and Windmill have heretofore executed and delivered a Receivables
Sale Agreement, dated as of December 21, 2001 (as amended, supplemented or
otherwise modified through the date hereof, the "Sale Agreement"),

     WHEREAS, the parties hereto desire to amend the Sale Agreement as provided
herein;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, the parties hereto hereby agree that
the Sale Agreement shall be and is hereby amended as follows:

     Section 1. Subject to the following terms and conditions, including without
limitation the conditions precedent set forth in Section 2, upon execution by
the parties hereto in the space provided for that purpose below, the Sale
Agreement shall be, and is hereby, amended as follows:

          (a) The defined term "Originators" appearing in Schedule I to the Sale
     Agreement is hereby amended in its entirety and as so amended shall read as
     follows:

               "Originators" means PerkinElmer, Inc., PerkinElmer Holdings,
          Inc., PerkinElmer Life Sciences, Inc., Receptor Biology, Inc.,
          PerkinElmer Instruments LLC, PerkinElmer Optoelectronics NC, Inc.,
          PerkinElmer Optoelectronics SC, Inc., PerkinElmer Canada, Inc.,
          Applied Surface Technology, Inc. and PerkinElmer Automotive Research,
          Inc.

          (b) Exhibit D to the Sale Agreement is hereby amended in its entirety
     to be and to read as set forth as Exhibit D to this Amendment.

          (c) Exhibit E to the Sale Agreement is hereby amended in its entirety
     to be and to read as set forth as Exhibit E to this Amendment.





<PAGE>


     Section 2. Section 1 of this Agreement shall become effective only once the
Agent has received, in form and substance satisfactory to the Agent, the
following:

          (a) A certificate of the Secretary of Applied Surface Technology, Inc.
     ("Applied Surface") certifying (i) the resolutions of Applied Surface's
     board of directors approving each Transaction Document to which it is a
     party, (ii) the name, signature, and authority of each officer who executes
     on Applied Surface's behalf a Transaction Document (on which certificate
     the Agent, each Purchaser Agent and each Purchaser may conclusively rely
     until a revised certificate is received), (iii) Applied Surface's
     certificate or articles of incorporation certified by the Secretary or
     Assistant Secretary, (iv) a copy of Applied Surface's by-laws and (v) good
     standing certificate issued by the Secretary of State of the jurisdiction
     where Applied Surface is organized.

          (b) A certificate of the Secretary of PerkinElmer Automotive Research,
     Inc. ("Automotive Research") certifying (i) the resolutions of Automotive
     Research's board of directors approving each Transaction Document to which
     it is a party, (ii) the name, signature, and authority of each officer who
     executes on Automotive Research's behalf a Transaction Document (on which
     certificate the Agent, each Purchaser Agent and each Purchaser may
     conclusively rely until a revised certificate is received), (iii)
     Automotive Research's certificate or articles of incorporation certified by
     the Secretary or Assistant Secretary, (iv) a copy of Automotive Research's
     by-laws and (v) good standing certificate issued by the Secretary of State
     of the jurisdiction where Automotive Research is organized.

          (c) All instruments and other documents required, or deemed desirable
     by the Agent, to perfect the Agent's first priority interest in the
     Receivables, Related Security, Collections, the Purchase Agreement and the
     Lock-Box Accounts of Applied Surface and Automotive Research in all
     appropriate jurisdictions.

          (d) Notwithstanding any provision to the Sale Agreement, the Lock-Box
     Agreements for Applied Surface and Automotive Research shall be delivered
     to the Agent by April 9, 2003.

          (e) UCC search reports from all jurisdictions the Agent requests.

          (f) Favorable opinions of counsel coveting such matters as any
     Purchaser Agent or the Agent may request.

          (g) Such other approvals, opinions or documents as the Agent or any
     Purchaser Agent may reasonably request.

     Section 3. The parties hereto consent to the execution and delivery of that
certain First Amendment to Purchase and Sale Agreement by the parties thereto.

     Section 4.1. To induce the Agent and the Purchasers to enter into this
Amendment, the Seller and Initial Collection Agent represent and warrant to the
Agent and the Purchasers that:

                                      -2-




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(a) the representations and warranties contained in the Transaction Documents,
are true and correct in all material respects as of the date hereof with the
same effect as though made on the date hereof (it being understood and agreed
that any representation or warranty which by its terms is made as of a specified
date shall be required to be true and correct in all material respects only as
of such specified date); (b) no Potential Termination Event exists; (c) this
Amendment has been duly authorized by all necessary corporate proceedings and
duly executed and delivered by each of the Seller and the Initial Collection
Agent, and the Sale Agreement, as amended by this Amendment, and each of the
other Transaction Documents are the legal, valid and binding obligations of the
Seller and the Initial Collection Agent, enforceable against the Seller and the
Initial Collection Agent in accordance with their respective terms, except as
enforceability may be limited by bankruptcy, insolvency or other similar laws of
general application affecting the enforcement of creditors' fights or by general
principles of equity; and (d) no consent, approval, authorization, order,
registration or qualification with any governmental authority is required for,
and in the absence of which would adversely effect, the legal and valid
execution and delivery or performance by the Seller or the Initial Collection
Agent of this Amendment or the performance by the Seller or the Initial
Collection Agent of the Sale Agreement, as amended by this Amendment, or any
other Transaction Document to which they are a party.

     Section 4.2. This Amendment may be executed in any number of counterparts
and by the different parties on separate counterparts and each such counterpart
shall be deemed to be an original, but all such counterparts shall together
constitute but one and the same Amendment.

     Section 4.3. Except as specifically provided above, the Sale Agreement and
the other Transaction Documents shall remain in full force and effect and are
hereby ratified and confirmed in all respects. The execution, delivery, and
effectiveness of this Amendment shall not operate as a waiver of any right,
power, or remedy of any Agent or any Purchaser under the Sale Agreement or any
of the other Transaction Documents, nor constitute a waiver or modification of
any provision of any of the other Transaction Documents. All defined terms used
herein and not defined herein shall have the same meaning herein as in the Sale
Agreement. The Seller agrees to pay on demand all costs and expenses (including
reasonable fees and expenses of counsel) of or incurred by the Agent and each
Purchaser Agent in connection with the negotiation, preparation, execution and
delivery of this Amendment.

     Section 4.4. This Amendment and the rights and obligations of the parties
hereunder shall be construed in accordance with and be governed by the law of
the State of Illinois.

                                      -3-




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     IN WITNESS WHEREOF, the parties have caused this Amendment to be executed
and delivered by their duly authorized officers as of the date first above
written.

                                  ABN AMRO BANK N.V., as the Agent,
                                    as the Committed Purchaser


                                  By:
                                     -------------------------------------------
                                  Title:
                                        ----------------------------------------


                                  By:
                                     -------------------------------------------
                                  Title:
                                        ----------------------------------------


                                  WINDMILL FUNDING CORPORATION


                                  By:
                                     -------------------------------------------
                                  Title:
                                        ----------------------------------------


                                  PERKINELMER RECEIVABLES COMPANY


                                  By: /s/ David C. Francisco
                                     -------------------------------------------
                                  Title: David C. Francisco, Assistant Treasurer
                                        ----------------------------------------


                                  PERKINELMER, INC.


                                  By: /s/ John L. Healy
                                     -------------------------------------------
                                  Title: John L. Healy, Assistant Clerk
                                        ----------------------------------------

                                      -4-




<PAGE>

                                              PERKINELMER RECEIVABLES COMPANY,
                                                as Buyer


                                              By:
                                                 -------------------------------
                                              Name:
                                                   -----------------------------
                                              Title:
                                                    ----------------------------


                                              CONSENTED AND AGREED TO:


                                              ABN AMRO BANK N.V., as Agent


                                              By: /s/ Therese Gremley
                                                 -------------------------------
                                              Name: THERESE GREMLEY
                                                   -----------------------------
                                              Title: Vice President
                                                    ----------------------------


                                              By: /s/ Bernard Koh
                                                 -------------------------------
                                              Name: BERNARD KOH
                                                   -----------------------------
                                              Title: Senior Vice President
                                                    ----------------------------


                                              WINDMILL FUNDING CORPORATION


                                              By:
                                                 -------------------------------
                                              Name:
                                                   -----------------------------
                                              Title:
                                                    ----------------------------


                                      -5-




<PAGE>
                                              By:
                                                 -------------------------------
                                                Name:
                                                     ---------------------------
                                                Title:
                                                      --------------------------


                                              CONSENTED AND AGREED TO:


                                              ABN AMRO BANK N.V., as Agent


                                              By:
                                                 -------------------------------
                                                Name:
                                                     ---------------------------
                                                Title:
                                                      --------------------------


                                              By:
                                                 -------------------------------
                                                Name:
                                                     ---------------------------
                                                Title:
                                                      --------------------------


                                              WINDMILL FUNDING CORPORATION


                                              By: /s/ Bernard J. Angelo
                                                 -------------------------------
                                                Name: Bernard J. Angelo
                                                     ---------------------------
                                                Title: Vice President
                                                      --------------------------

                                      -5-




<PAGE>


                     GUARANTOR'S ACKNOWLEDGMENT AND CONSENT

     The undersigned, PerkinElmer, Inc., has heretofore executed and delivered
the Limited Guaranty dated as of December 21, 2001 (the "Guaranty") and hereby
consents to the Amendment to the Sale Agreement as set forth above and confirms
that the Guaranty and all of the undersigned's obligations thereunder remain in
full force and effect. The undersigned further agrees that the consent of the
undersigned to any further amendments to the Sale Agreement shall not be
required as a result of this consent having been obtained, except to the extent,
if any, required by the Guaranty referred to above.



                                               PERKINELMER, INC.



                                               By: /s/ Robert F. Friel
                                                  ------------------------------
                                               Title: Robert F. Friel, SVP & CFO
                                                     ---------------------------