EXHIBIT 4.2

NEITHER THIS WARRANT NOR THE COMMON STOCK WHICH MAY BE ACQUIRED UPON THE
EXERCISE HEREOF HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), OR UNDER THE SECURITIES LAWS OF ANY STATE AND
MAY NOT BE PLEDGED, SOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE
REGISTRATION STATEMENT WITH RESPECT THERETO UNDER THE SECURITIES ACT AND
COMPLIANCE WITH ANY APPLICABLE STATE SECURITIES LAW, OR UNLESS THE COMPANY
RECEIVES AN OPINION OF COUNSEL, SATISFACTORY TO THE COMPANY, THAT SUCH
REGISTRATION IS NOT REQUIRED.


                                                          For the Purchase
                                                          of 44,810 shares of
No. 1                                                     Common Stock


                           WARRANT FOR THE PURCHASE OF
                             SHARES OF COMMON STOCK
                                       OF
                             SENTIGEN HOLDING CORP.
                            (A Delaware Corporation)



   SENTIGEN HOLDING CORP., a Delaware corporation (the "Company"), hereby
certifies that THEODORE M. SERURE, or his, her or its registered assigns (the
"Registered Holder"), is entitled, subject to the terms set forth below, to
purchase from the Company, at any time or from time to time until November 21,
2005 ("Expiration Date"), Forty-Four Thousand Eight Hundred and Ten (44,810)
shares of Common Stock, $.01 par value, of the Company ("Common Stock"), at a
purchase price equal to $6.00 per share. The number of shares of Common Stock
purchasable upon exercise of this Warrant, and the purchase price per share,
each as adjusted from time to time pursuant to the provisions of this Warrant,
are hereinafter referred to as the "Warrant Stock" and the "Purchase Price,"
respectively.

   This Warrant is issued to Registered Holder in consideration of Registered
Holder's introduction to the Company of investors in a private offering of the
Company's Common Stock consummated on November 21, 2000 ("Private Placement").

   1.      Exercise.

           (a) This Warrant may be exercised by the Registered Holder, in whole
or in part, by surrendering this Warrant, with the purchase form appended hereto
as Exhibit I duly executed by such Registered Holder, at the principal office of
the Company, or at such other office or agency as the Company may designate,
accompanied by payment in full, in lawful money of the United States, of the
Purchase Price payable in respect of the number of full shares of Warrant Stock
purchased upon such exercise.

           (b) Each exercise of this Warrant shall be deemed to have been
effected immediately prior to the close of business on the day on which this
Warrant shall have been surrendered to the Company as provided in subsection
1(a) above. At such time, the person or persons in whose name or names any
certificates for Warrant Stock shall be issuable upon such exercise as provided


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in subsection 1(c) below shall be deemed to have become the holder or holders of
record of the Warrant Stock represented by such certificates.

           (c) As soon as practicable after the exercise of this Warrant in full
or in part, and in any event within 10 days thereafter, the Company at its
expense will cause to be issued in the name of, and delivered to, the Registered
Holder, or, subject to the terms and conditions hereof, as such Holder (upon
payment by such Holder of any applicable transfer taxes) may direct:

                  (i) a certificate or certificates for the number of full
shares of Warrant Stock to which such Registered Holder shall be entitled upon
such exercise, and

                  (ii) in case such exercise is in part only, a new warrant or
warrants (dated the date hereof) of like tenor, calling in the aggregate on the
face or faces thereof for the number of shares of Warrant Stock equal (without
giving effect to any adjustment therein) to the number of such shares called for
on the face of this Warrant minus the number of such shares purchased by the
Registered Holder upon such exercise as provided in subsection 1(a) above.

   2.      Adjustments.

           (a) If the outstanding shares of the Company's Common Stock shall be
subdivided or split into a greater number of shares or a dividend in Common
Stock shall be paid or split, in respect of Common Stock, the Purchase Price in
effect immediately prior to such subdivision or at the record date of such
dividend, shall simultaneously with the effectiveness of such subdivision or
split, or immediately after the record date of such dividend be proportionately
reduced. If the outstanding shares of Common Stock shall be combined or
reverse-split into a smaller number of shares, the Purchase Price in effect
immediately prior to such combination or reverse split shall, simultaneously
with the effectiveness of such combination or reverse split, be proportionately
increased. When any adjustment is required to be made in the Purchase Price, the
number of shares of Warrant Stock purchasable upon the exercise of this Warrant
shall be changed to the number determined by dividing (i) an amount equal to the
number of shares issuable upon the exercise of this Warrant immediately prior to
such adjustment, multiplied by the Purchase Price in effect immediately prior to
such adjustment, by (ii) the Purchase Price in effect immediately after such
adjustment.

           (b) If there shall occur any capital reorganization or
reclassification of the Company's Common Stock (other than a change in par value
or a subdivision or combination as provided for in subsection 2(a) above), or
any consolidation or merger of the Company with or into another corporation, or
the payment of a liquidating distribution then, as part of any such
reorganization, reclassification, consolidation merger or liquidating
distribution, lawful provision shall be made so that the Registered Holder of
this Warrant shall have the right thereafter to receive upon the exercise hereof
(to the extent, if any, still exercisable) the kind and amount of shares of
stock or other securities or property which such Registered Holder would have
been entitled to receive if, immediately prior to any such reorganization,
reclassification, consolidation, merger or liquidating distribution, as the case
may be, such Registered Holder had held the number of shares of Common Stock
which were then purchasable upon the exercise of this Warrant. In any such case,
appropriate adjustment (as reasonably determined by the Board of Directors of
the Company) shall be made in the application of the provisions set forth herein
with respect to the rights and interests thereafter of the Registered Holder of
this Warrant such that the provisions set forth in this Section 2 (including
provisions with respect to the Purchase Price) shall thereafter be applicable,
as nearly as is reasonably practicable, in relation to any shares of stock or
other securities or property thereafter deliverable upon the exercise of this
Warrant.


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<PAGE>



           (c) Notwithstanding the provisions of subsection 2(b) above, in the
event of any consolidation or merger of the Company with or into another
corporation, as a result of which the holders of the Company's outstanding
voting securities prior to the consolidation or merger own less than 50% of the
voting securities of the Company or surviving corporation after the
consolidation or merger, at any time during the period during which this Warrant
may be exercised (a "Merger"), the Company shall provide to the Registered
Holder fifteen (15) days advance written notice of the record date for such
Merger in accordance with Section 5 hereof. If, in connection with such Merger,
one share of the Company's Common Stock would be exchanged for securities or
other consideration valued at more than the Purchase Price, then this Warrant
shall terminate at the closing of the Merger. Any exercise by the Registered
Holder prior to the closing of the Merger may be conditioned upon such closing
occurring.

           (d) Upon the happening of any event requiring an adjustment of the
exercise price hereunder, the Company shall forthwith give written notice
thereto to the registered holder of this Warrant stating the adjusted exercise
price and the adjusted number of shares purchasable upon the exercise hereof
resulting from such event and setting forth in reasonable detail the method of
calculation and the facts upon which such calculation is based.

   3.      Conversion Right.

           (a) Determination of Amount. In lieu of the payment of the Purchase
Price in cash, the Holder shall have the right (but not the obligation) to
convert this Warrant, in whole or in part, into Common Stock ("Conversion
Right"), as follows: upon exercise of the Conversion Right, the Company shall
deliver to the Holder (without payment by the Holder of any of the Exercise
Price) that number of shares of Common Stock equal to the quotient obtained by
dividing (x) the "Value" (as defined below) of the portion of the Warrant being
converted at the time the Conversion Right is exercised by (y) the Market Price.
The "Value" of the portion of the Warrant being converted shall equal the
remainder derived from subtracting (i) the Exercise Price multiplied by the
number of shares of Common Stock being converted from (ii) the Market Price of
the Common Stock multiplied by the number of shares of Common Stock being
converted. As used herein, the term "Market Price" at any date shall be deemed
to be the last reported sale price of the Common Stock on such date, or, in case
no such reported sale takes place on such day, the average of the last reported
sale prices for the immediately preceding three trading days, in either case as
officially reported by the principal securities exchange on which the Common
Stock is listed or admitted to trading, or, if the Common Stock is not listed or
admitted to trading on any national securities exchange or if any such exchange
on which the Common Stock is listed is not its principal trading market, the
last reported sale price as furnished by the National Association of Securities
Dealers, Inc. ("NASD") through the Nasdaq National Market or SmallCap Market,
or, if applicable, the OTC Bulletin Board, or if the Common Stock is not listed
or admitted to trading on any of the foregoing markets, or similar organization,
as determined in good faith by resolution of the Board of Directors of the
Company, based on the best information available to it.

           (b) Exercise of Conversion Right. The Conversion Right may be
exercised by the Holder on any business day on or after the Warrant is
exercisable and not later than the Expiration Date by delivering the Warrant
with a duly executed exercise form attached hereto with the conversion section
completed to the Company, exercising the Conversion Right and specifying the
total number of shares of Common Stock the Holder will purchase pursuant to such
conversion.


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<PAGE>



   4.      Registration Rights.

           (a) Grant of Right. The resale of the Common stock underlying this
Warrant will be included in the Registration Statement filed on behalf of the
investors in the Company's Private Placement. The Company shall use its best
efforts to have the Registration Statement declared effective by the Securities
and Exchange Commission ("SEC") and be kept current and effective until all the
Common Stock registered thereunder are sold or can be sold freely under an
appropriate exemption, without limitation.

           (b) Fees and Expenses. In any registration statement in which Common
Stock are included pursuant to this Section, the Company shall bear all expenses
and pay all fees incurred in connection therewith, excluding underwriting
discounts and commissions payable with respect to the Common Stock and the fees
and expenses of any professionals engaged by the Registered Holder, but
including the expenses of providing a reasonable number of copies of the
prospectus contained therein to the Registered Holder.

           (c) Indemnification by Company. The Company shall indemnify the
holder of the Common Stock to be sold pursuant to any registration statement
hereunder, the officers and directors of each holder and each person, if any,
who controls such holders within the meaning of Section 15 of the Act or Section
20(a) of the Securities Exchange Act of 1934, as amended ("Exchange Act"), or
any state securities law or regulation, against all loss, claim, damage, expense
or liability (including all reasonable attorneys' fees and other expenses
reasonably incurred in investigating, preparing or defending against any claim
whatsoever incurred by the indemnified party in any action or proceeding between
the indemnitor and indemnified party or between the indemnified party and any
third party or otherwise) to which any of them may become subject under the
Securities Act, the Exchange Act or any other statute or at common law or
otherwise under the laws of foreign countries, arising from such registration
statement or based upon any untrue statement or alleged untrue statement of a
material fact contained in (i) any preliminary prospectus, the registration
statement or prospectus (as from time to time each may be amended and
supplemented); (ii) any post-effective amendment or amendments or any new
registration statement and prospectus in which is included the Common Stock; or
(iii) any application or other document or written communication (collectively
called "application") executed by the Company or based upon written information
furnished by the Company in any jurisdiction in order to qualify the Common
Stock under the securities laws thereof or filed with the SEC, any state
securities commission or agency, Nasdaq or any securities exchange; or the
omission or alleged omission therefrom of a material fact required to be stated
therein or necessary to make the statements therein, in light of the
circumstances under which they were made, not misleading, unless such statement
or omission is made in reliance upon, and in conformity with, written
information furnished to the Company by and with respect to such registered
holders ("Purchaser Information") expressly for use in any preliminary
prospectus, the registration statement or prospectus, or any amendment or
supplement thereof, or in any application, as the case may be, or unless the
indemnities failed to deliver a final prospectus in which the material
misstatement or omission was corrected. The Company agrees promptly to notify
such Registered Holder of the commencement of any litigation or proceedings
against the Company or any of its officers, directors or controlling persons in
connection with the issue and sale or resale of the Common Stock or in
connection with the registration statement or prospectus.

           (d) Successors and Assigns. The registration rights granted to the
Registered Holder inure to the benefit of all the Registered Holders'
successors, heirs, pledges, assignees, transferees and purchasers of the Common
Stock.


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<PAGE>



   5. Fractional Shares. The Company shall not be required upon the exercise of
this Warrant to issue any fractional shares, but shall round up the number of
shares to the next whole share calculated on a cumulative basis after taking
into account all prior exercises and the number of shares issued thereby.

   6. Limitation on Sales. Each holder of this Warrant acknowledges that this
Warrant and the Warrant Stock have not been registered under the Securities Act,
as now in force or hereafter amended, or any successor legislation, and agrees
not to sell, pledge, distribute, offer for sale, transfer or otherwise dispose
of this Warrant or any Warrant Stock issued upon its exercise in the absence of
(a) an effective registration statement under the Securities Act as to this
Warrant or such Warrant Stock and registration or qualification of this Warrant
or such Warrant Stock under any applicable Blue Sky or state securities law then
in effect, or (b) an opinion of counsel, satisfactory to the Company, that such
registration and qualification are not required. Certificates representing
Warrant Stock shall bear a legend to such effect.

   7.      Notices of Record Date.  In case:

           (a) the Company shall take a record of the holders of its Common
Stock (or other stock or securities at the time deliverable upon the exercise of
this Warrant) for the purpose of entitling or enabling them to receive any
dividend or other distribution (other than a dividend or distribution payable
solely in capital stock of the Company or out of funds legally available
therefor), or to receive any right to subscribe for or purchase any shares of
stock of any class or any other securities, or to receive any other right, or

           (b) of any capital reorganization of the Company, any
reclassification of the capital stock of the Company, any consolidation or
merger of the Company with or into another corporation (other than a
consolidation or merger in which the Company is the surviving entity), or any
transfer of all or substantially all of the assets of the Company, or

           (c) of the voluntary or involuntary dissolution, liquidation or
winding-up of the Company, then, and in each such case, the Company will mail or
cause to be mailed to the Registered Holder of this Warrant a notice specifying,
as the case may be, (i) the date on which a record is to be taken for the
purpose of such dividend, distribution or right, and stating the amount and
character of such dividend, distribution or right, or (ii) the effective date on
which such reorganization, reclassification, consolidation, merger, transfer,
dissolution, liquidation or winding-up is to take place, and the time, if any is
to be fixed, as of which the holders of record of Common Stock (or such other
stock or securities at the time deliverable upon the exercise of this Warrant)
shall be entitled to exchange their shares of Common Stock (or such other stock
or securities) for securities or other property deliverable upon such
reorganization, reclassification, consolidation, merger, transfer, dissolution,
liquidation or winding-up. The Company shall use reasonable efforts to mail any
such notice at least ten (10) days prior to the record date or effective date
for the event specified in such notice, provided that the failure to mail such
notice shall not affect the legality or validity of any such action.

   8. Reservation of Stock. The Company will at all times reserve and keep
available, solely for issuance and delivery upon the exercise of this Warrant,
such shares of Warrant Stock and other stock, securities and property, as from
time to time shall be issuable upon the exercise of this Warrant.

   9. Replacement of Warrants.  Upon receipt of evidence reasonably satisfactory
to the Company of the loss, theft, destruction or mutilation of this Warrant and
(in the case of loss, theft or destruction) upon delivery of an indemnity


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<PAGE>


agreement (with surety if reasonably required) in an amount reasonably
satisfactory to the Company, or (in the case of mutilation) upon surrender and
cancellation of this Warrant, the Company will issue, in lieu thereof, a new
Warrant of like tenor.

   10. Mailing of Notices, etc. All notices and other communications from the
Company to the Registered Holder of this Warrant shall be mailed by first-class
certified or registered mail, postage prepaid, or sent by reputable overnight
delivery to the address furnished to the Company by the last Registered Holder
of this Warrant who shall have furnished an address to the Company in writing.
All notices and other communications from the Registered Holder of this Warrant
to the Company shall be mailed by first-class certified or registered mail,
postage prepaid, or sent by reputable overnight delivery to the Company at its
offices at 580 Marshall Street, Phillipsburg, New Jersey 08865, Attention:
Corporate Secretary, or such other address as the Company shall so notify the
Registered Holder.

   11. No Rights as Stockholder.  Until the exercise of this Warrant, the
Registered Holder of this Warrant shall not have or exercise any rights by
virtue hereof as a stockholder of the Company.

   12. Change or Waiver.  Any term of this Warrant may be changed or waived only
by an instrument in writing signed by the party against which enforcement of the
change or waiver is sought.

   13. Headings.  The headings in this Warrant are for purposes of reference
only and shall not limit or otherwise affect the meaning of any provision of
this Warrant.

   14. Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the State of New York.

   15. Venue. Any controversy, dispute or claim between the Registered Holder
and the Company arising out of or relating to this Warrant, or its
interpretation, application, implementation, breach or enforcement which the
parties are unable to resolve by mutual agreement, shall be adjudicated in the
courts of the State of New York located in the County of New York or the United
States District Court for the Southern District of New York and the Registered
Holder, by acceptance of this Warrant, hereby submits to the exclusive
jurisdiction of such courts.


                                 SENTIGEN HOLDING CORP.

                                     /s/ Joseph K. Pagano
                                 By:_________________________________________

                                 Title: President and Chairman of the Board


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<PAGE>


                                    EXHIBIT I



                                  PURCHASE FORM

                                                  Dated:



To:        Sentigen Holding Corp.
           580 Marshall Street
           Phillipsburg, New Jersey 08865
           Attention:  Corporate Secretary


   The undersigned pursuant to the provisions set forth in the attached Warrant,
hereby irrevocably elects to purchase ______ shares of Common Stock covered by
such Warrant and herewith makes payment of $________, representing the full
purchase price for such shares at the price per share provided for in such
Warrant.

                                      -or-

   The undersigned pursuant to the provisions set forth in the attached warrants
hereby irrevocably elects to convert its right to purchase ____________ shares
of Common Stock purchasable under the Warrant into __________ shares of Common
Stock (based on a "Market Price" of $________ per share of Common Stock).

   The undersigned has had the opportunity to ask questions of and receive
answers from the officers of the Company regarding the affairs of the Company
and related matters, and has had the opportunity to obtain additional
information necessary to verify the accuracy of all information so obtained.

   The undersigned understands that the shares have not been registered under
the Securities Act of 1933, as amended or the securities laws of any other
jurisdiction, and hereby represents to the Company that the undersigned is
acquiring the shares for its own account, for investment, and not with a view
to, or for sale in connection with, the distribution of any such shares.

                           Signature:     ______________________________

                           [Print Name]   ______________________________

                           Address:       ______________________________



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