EX-10.1






AMENDMENT NO. 1 TO




SECURITIES PURCHASE AGREEMENT




AMENDMENT NO. 1, dated as of May 24, 2006 (this “Amendment”), to the Securities
Purchase Agreement, dated as of May 16, 2006 (the “Purchase Agreement”), by and among Sipex
Corporation, a Delaware corporation (the “Company”), and the Buyers listed on the Schedule
of Buyers attached thereto as Exhibit A (each a “Buyer” and collectively, the
“Buyers”). Each capitalized term used and not otherwise defined herein shall have the
meaning assigned to such term in the Purchase Agreement.



WHEREAS, pursuant to the Purchase Agreement, the Company sold to the Buyers, and each Buyer
has severally purchased from the Company, the principal amount of Notes and number of Warrants set
forth opposite their respective names on Exhibit A to the Purchase Agreement;



WHEREAS, the Company and the Buyers desire to modify the Purchase Agreement in accordance with
the provisions of Section 9(f) thereof; and



WHEREAS, the undersigned represent Investors holding at least 66 2/3% of the Conversion Shares
and Warrant Shares, determined as if all of the Notes held by Buyers then outstanding have been
converted into Conversion Shares and all Warrants then outstanding have been exercised for Warrant
Shares without regard to any limitations on the conversion of the Notes or on the exercise of the
Warrants.



NOW, THEREFORE, in consideration of the mutual agreements herein contained and other good and
valuable consideration, the sufficiency and receipt of which are hereby acknowledged, the parties
hereto agree as follows:



Section 1. Amendments to the Purchase Agreement. 



(a) Section 4 of the Purchase Agreement shall be amended to add Section 4(aa) which shall read
as follows:




DTC Settlement. The Company will use its reasonable best efforts to make the
Notes and Warrants, other than the Notes and Warrants issued to Rodfre Holdings LLC,
eligible to be registered for settlement through DTC no later than fifteen (15) days
following the satisfaction of the Exchange Act Filing Condition (as defined in the
Indenture).



Section 2. Acknowledgement of Scrivener’s Error. The parties hereby acknowledge that
the inclusion of the “Acknowledged and Agreed” signature block for Piper Jaffray & Co. was a
scrivener’s error and that Piper Jaffray’s acknowledgement was unnecessary for the execution of the
Purchase Agreement.



Section 3. Governing Law. All questions concerning the construction, validity,
enforcement and interpretation of this Amendment shall be governed by the internal laws of the
State of New York, without giving effect to any choice of law or conflict of law provision or rule
(whether of the State of New York or any other jurisdictions) that would cause the application of
the laws of any jurisdictions other than the State of New York.



Section 4. Counterparts. This Amendment may be executed in identical counterparts,
each of which shall be deemed an original but all of which shall constitute one and the same
agreement. This Amendment, once executed by a party, may be delivered to the other parties hereto
by facsimile transmission of a copy of this Agreement bearing the signature of the party so
delivering this Amendment.



Section 5. Headings. The headings of this Amendment are for convenience of reference
only and shall not limit or otherwise affect the meaning thereof.



Section 6. Effect of Amendment. Except as expressly amended by this Amendment, the
Purchase Agreement shall remain in full force and effect as the same was in effect immediately
prior to the effectiveness of this Amendment. All references in the Purchase Agreement to “this
Agreement” shall be deemed to refer to the Purchase Agreement as amended by this Amendment.



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



	 	 	 
	SIPEX CORPORATION

By:

	 	

   /s/    Ralph Schmitt                                  
	
 
	 	 
	
 
	 	Name: Ralph Schmitt

Title: President and Chief Executive Officer







	 	 	BUYERS





(print full legal name of Buyer)





By:



 (signature of authorized representative)





Name:




Its:



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



	 	 	 
	SIPEX CORPORATION

By:

	 	

                                     
	
 
	 	 
	
 
	 	Name: Ralph Schmitt

Title: President and Chief Executive Officer







BUYERS




Rodfre Holding LLC



(print full legal name of Buyer)





By: /s/ Joe Prudente, Manager and Director



 (signature of authorized representative)





Name: Joe Prudente, Manager and Director




Its:



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



	 	 	 
	SIPEX CORPORATION

By:

	 	

                                     
	
 
	 	 
	
 
	 	Name: Ralph Schmitt

Title: President and Chief Executive Officer







BUYERS




Quantum Partners LDC



(print full legal name of Buyer)





By: /s/ Jay A. Schoenfarber



 (signature of authorized representative)





Name: Jay A Schoenfarber




Its: Attorney-in-Fact



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



	 	 	 
	SIPEX CORPORATION

By:

	 	

                                     
	
 
	 	 
	
 
	 	Name: Ralph Schmitt

Title: President and Chief Executive Officer







BUYERS




THE NORTHWESTERN MUTUAL LIFE INSURANCE COMPANY



(print full legal name of Buyer)





By: /s/ Jerome R. Baier



 (signature of authorized representative)





Name: Jerome R. Baier




Its: Authorized Representative



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



	 	 	 
	SIPEX CORPORATION

By:

	 	

                                     
	
 
	 	 
	
 
	 	Name: Ralph Schmitt

Title: President and Chief Executive Officer







BUYERS




THE NORTHWESTERN MUTUAL LIFE INSURANCE COMPANY FOR ITS GROUP
ANNUITY SEPARATE ACCOUNT



(print full legal name of Buyer)





By: /s/ Jerome R. Baier



 (signature of authorized representative)





Name: Jerome R. Baier




Its: Authorized Representative




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