<PAGE>

                                                                   Exhibit 4.1



NUMBER                          LOGO                         SHARES

BDAL                     BRUKER DALTONICS INC.           CUSIP 116795 10 5
 COMMON STOCK         INCORPORATED UNDER THE LAWS         SEE REVERSE FOR
PAR VALUE $.01          OF THE STATE OF DELAWARE        CERTAIN DEFINITIONS

THIS CERTIFIES THAT

IS THE OWNER OF

                FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK,
                           PAR VALUE $.01 PER SHARE, OF
                              BRUKER DALTONICS INC.

(the "Corporation"), a Delaware corporation. The shares represented by this
certificate are transferable only on the stock transfer books of the
Corporation by the holder of record hereof, or by the holder's duly
authorized attorney or legal representative, upon the surrender of this
certificate properly endorsed.
This certificate is not valid until countersigned by the Corporation's
transfer agent and registrar.

     IN WITNESS WHEREOF, the Corporation has caused this certificate to be
executed by the facsimile signatures of its duly authorized officers and has
caused a facsimile of its corporate seal to be hereunto affixed.

Dated:

John J. Hulburt                                     Frank H. Laukien
Treasurer                                      PRESIDENT, CHAIRMAN AND CHIEF
                                                    EXECUTIVE OFFICER


Countersigned and Registered:
AMERICAN STOCK TRANSFER & TRUST COMPANY
Transfer Agent and Registrar,

By
                         Authorized Signature

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                                BRUKER DALTONICS INC.

     A statement of the rights, preferences, privileges and restrictions
granted to or imposed upon the respective classes or series of shares of
stock of the Corporation, and upon the holders thereof as established by the
Certificate of Incorporation or by any certificate of determination of
preferences, and the number of shares constituting each series or class and
the designations thereof, may be obtained by any stockholder of the
Corporation upon request and without charge from the Secretary of the
Corporation at the principal office of the Corporation.

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<TABLE>
<S>                                            <C>
TEN COM - as tenants in common                 UNIF-GIFT MIN ACT- ............Custodian...........
TEN ENT - as tenants by the entireties                               Cust                  (Minor)
JT TEN  - as joint tenants with right of                             under Uniform Gifts to Minors
          survivorship and not as tenants                            Act .........................
          in common                                                              (State)

                                               UNIF TRF MIN ACT- ........Custodian (until age ....)
                                                                  (Cust)
                                                                 ...........under Uniform Transfers
                                                                   (Minor)
                                                                 to Minors Act ....................
                                                                                    (State)
</TABLE>

     Additional abbreviations may also be used though not in the above list.

FOR VALUE RECEIVED, _____________________ hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
    IDENTIFYING NUMBER OF ASSIGNEE
----------------------------------------

----------------------------------------

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(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

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----------------------------------------------------------------------- Shares
of the capital stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint

--------------------------------------------------------------------- Attorney
to transfer the said stock on the books of the within named Corporation with
full power of substitution in the premises.

Dated ----------------------------------------------

                       -----------------------------------------------------
                       NOTICE: THE SIGNATURE OF THIS ASSIGNMENT MUST CORRESPOND
                               WITH THE NAME AS WRITTEN UPON THE FACE OF THE
                               CERTIFICATE IN EVERY PARTICULAR WITHOUT
                               ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.

SIGNATURE(S) GUARANTEED:

BY
  ------------------------------------------------------------------------
THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH
MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT
TO S.E.C. RULE 17Ad-15