<PAGE>
                                                                   EXHIBIT 10.50




November 13, 2001

Susan Evans Ph.D.



Dear Sue:

We are pleased to formally extend to you an offer of employment for the position
of Vice President Product Development with Caliper Technologies Corp. (Caliper).
In this position you will report to me.

The primary responsibilities of this position include: developing the
infrastructure and directing the technical activities of the product development
function from product conception through transition to manufacturing. These
activities include instrument engineering, software engineering, assay
development and product microfluidics through all the stages of the product
lifecycle for successful delivery. In this position you will be a company
officer and a member of the executive team with additional responsibility for
contributing to the strategic planning and management of the company

To compensate you for your efforts in this position, you will receive a
compensation package including base salary, performance bonus, stock options and
a comprehensive benefits plan.

BASE SALARY: your base salary will be $20,417 per month (equivalent to $245,004
per annum), subject to standard payroll deductions and withholdings. This
position is classified as exempt.

PERFORMANCE BONUS: you will be eligible for an annual bonus under the Caliper
performance bonus plan beginning January 1, 2002. In the position you have been
offered, your annual bonus opportunity would be equal to 40% of your annualized
base salary. Actual payment of this bonus is subject to your performance and the
performance of the company during the year.

EQUITY: I will be recommending to the board of directors the approval of a stock
option grant for 175,000 shares of Common Stock of Caliper. The price per share
for this option will be fixed based on the closing sales price (or closing bid,
if no sales are reported) on the last trading day prior to the date of grant. It
is our intent to have your date of grant be your first day of employment. The
shares subject to this option will vest over a four-year period with 25% of the
shares vesting one (1) year from your start date, and thereafter the shares
shall vest at a rate of 1/48th of the shares per month at the end of each of the
remaining 36 months. The option will be granted pursuant to the Company's 1999
Equity Incentive Plan.

EMPLOYEE STOCK PURCHASE PLAN: Based on an anticipated start date after November
20, 2001, you will be eligible to participate in Caliper's Employee Stock
Purchase Plan effective June 1, 2002.
<PAGE>
Susan Evans
November 13, 2001
Page 2


BENEFITS: you will receive all the employment benefits available to full time,
regular exempt employees of the Caliper. These benefits include medical, dental,
vision and life insurance plans including a term executive life insurance policy
with a benefit of $500,000 and an executive life insurance benefit of an
additional $500,000, for which the premiums are paid 100% by the Company,
accrual of fifteen days vacation during the year, eleven paid holidays, five
days flexible time off, five days sick leave and a 401(k) plan.

RELOCATION: It is our understanding that you have not completed your relocation
to the San Francisco Bay Area. To assist you in this activity, the company will
provide you with relocation assistance. Please see the attached summary of
Caliper Technologies Corp. Relocation Coverage Your relocation must occur within
four years of date of employment.

CHANGE OF CONTROL: In this position, you will be eligible for compensation
protection should your employment terminate due to a Change of Control. The
terms of this protection are:

      Severance Pay:

      If your employment is terminated (including a Constructive Termination)
      during the 13 months following a Change of Control for any reason other
      than for Cause, then if you execute an effective waiver and release of all
      claims, you will receive monthly consulting payments equal to your base
      salary at time of termination for 12 months or until employed by another
      company, whichever is less, and to the extent and for so long as (but not
      to exceed 12 months) you are not eligible to receive comparable health
      insurance coverage from another employer, Caliper Technologies Corp. will
      provide you and your eligible dependents with COBRA continuation of
      coverage, at its expense provided that you completes the requisite forms
      to elect and obtain such continued coverage in timely manner.

      Equity:

      In addition to the vesting acceleration provisions stated in the Company's
      1999 Stock Option Plan if your employment is terminated (including without
      limitation Constructive Termination) during the 13 months following a
      Change of Control for any reason except for Cause, then on the date of
      termination you will receive accelerated vesting of 30 months for all
      outstanding stock options. Acceleration of vesting will not be available
      or provided, however, if the Change of Control is to be a "pooling of
      interests" transaction and the Company's outside auditors determine that
      such acceleration of vesting would prevent the Company from participating
      in a "pooling of interests" transaction.

In accordance with the Immigration Reform & Control Act of 1986, employment in
the United States is conditional upon proof of eligibility to legally work in
the United States. On your first day of employment, you will need to provide us
with this proof. If you do not have these documents, please contact me prior to
your first day of employment.


Your employment with Caliper is voluntarily entered into and you are free to
resign at any time. Similarly, Caliper is free to conclude an employment
relationship where it believes it is in its interest at any time. While we hope
our relationship will be mutually beneficial, it should be recognized that
neither you, nor we have entered into any contract of employment expressed or
implied. Our relationship is and always will be one of voluntary employment "at
will".
<PAGE>
Susan Evans
November 13, 2001
Page 3


As an employee of Caliper you will have access to confidential information and
you may, during the course of your employment, develop information or inventions
that will be the property of Caliper. To protect the interests of Caliper, you
will be required to sign the Company's Proprietary Information and Inventions
Agreement as a condition of your starting employment. We wish to impress upon
you that we do not wish you to bring with you any confidential or proprietary
material of any former employer or to violate any other obligations you may have
to your former employer.

This offer letter is an offer of employment and is not intended and shall not be
construed as a contract proposal or contract of employment.

This written offer constitutes all conditions and agreements made on behalf of
Caliper Technologies Corp. and supersedes any previous verbal commitments by the
Company. No representative other than myself has any authority to alter or add
to any of the terms and conditions herein.

Please contact Richard Butts or me if you have any questions and/or to indicate
your response to this offer. Upon your acceptance please sign and return the
original while retaining the copy of this offer for your records. You may also
send your signed copy to our confidential fax number: 650-623-0504. I have also
enclosed a Proprietary Information and Inventions Agreement. This employment
offer expires on November 20, 2001 at 5:00 pm PST.

We believe we are far along in the process of assembling a "world class" team
and a broad and deep technology and product portfolio. Your experience and
talents will be a strong addition. We hope that you will join us in building a
preeminent company.

Regards,

/s/ Daniel L. Kisner
---------------------

Daniel L. Kisner, M.D.
Chief Executive Officer & President



Accepted:  /s/ Sue Evans                  Date: 12/13/01
          --------------------            --------------------------------------

Enclosures
<PAGE>
CALIPER TECHNOLOGIES CORP. RELOCATION COVERAGE

The following information concerning moving procedures is intended to assist you
in arranging for the relocation of your household effects.

-     MOVING

      -     GENERAL

      -     Caliper Technologies Corp. will pay for packing and transporting
            your household goods. Unpacking, storage, delivery from storage, and
            replacement value insurance coverage are included in the service.

      -     Household goods will be moved from one location at origin to one
            location at destination with allowance for thirty (30) days of
            temporary storage.

      -     Household goods include such items as furniture, linen, bedding,
            china, silverware, rugs, appliances, kitchen utensils, clothing and
            hand tools.

      -     Maximum amount of weight for the movement of household effects shall
            be limited to 50,000 pounds and two drivable cars.

-         ARRANGEMENTS

      -     Caliper Technologies Corp. has a selected moving company, Ace
            Relocation Systems/Atlas Van Lines (carrier) will establish dates
            for packing, loading and deliver in conjunction with you. Normally,
            the carrier needs two weeks notice to schedule a move.

      -     Please advise Human Resources Department of your moving date and
            where you may be reached after the date.

      -     If a problem should arise with your move, immediately call Human
            Resources for assistance.

-        INSURANCE COVERAGE

      -     Ace Relocation Systems/Atlas Van Lines will provide replacement
            value insurance coverage to completely protect your household goods
            while en route or in temporary storage. (Coverage is based on $3.50
            per pound of actual weight shipped).

      -     Antiques and articles of high or special value requiring special
            handling or additional insurance will be your responsibility.

-        PACKING AND UNPACKING

      -     The carrier must pack your furnishings and provide crating where
            necessary. Items packed by you may not be covered by the carrier's
            liability. If you wish to pack certain items, we suggest you discuss
            liability coverage for those items with the carrier.

      -     A responsible member of your family should be present during packing
            and loading. The carrier and Caliper. are liable only for articles
            included on the carrier's inventory. The carrier and Caliper are not
            responsible for any articles left in your residence.

      -     A responsible member of your family should be present when the
            carrier's van is unloaded. If there are noticeable shortages or
            damage caused by the carrier upon delivery, such notations should be
            noted on the bill of lading or inventory list at the time of
            unloading. Claims against the carrier are more difficult to support
            if damage or missing items are not reported at the time of delivery.

      -     The carrier will unpack all cartons packed by them at your request.
<PAGE>
      -     It is the carrier's responsibility to place the furniture and
            cartons in your new residence as indicated.

-         STORAGE

      -     If necessary, Caliper will pay for one month's storage normally at
            or near the Destination City. Storage includes warehouse handling,
            one month's storage, and a single delivery to the new residence.

-     MISCELLANEOUS

      -     Appliances

            -     Due to age and wear of parts, household appliances (including
                  televisions, radios, etc.) are susceptible to damage from
                  vibration in transit. Therefore, neither Caliper nor the
                  carrier can assume responsibility for malfunctioning of any
                  appliances except where there is observable damage to the
                  appliance. Appliance removal and installation at origin and
                  destination will be paid by the employee.

                  -     Freezers, frozen food and refrigerators.

                  -     Please discuss the proper handling of these items with
                        the carrier. Carriers will not normally transport a
                        loaded freezer, not only because of potential food
                        spoilage, but also because of potential contamination of
                        the freezer.

                  -     Caliper will not assume special charges for handling a
                        loaded freezer. Neither the carrier nor Caliper will
                        assume liability for food spoilage.

                  -     Refrigerators must be cleaned and dried inside before
                        moving to prevent contamination (24 hours prior to
                        loading is recommended).

-     Articles not acceptable by carriers.

      -     Carriers will not accept for transportation: flammable materials,
            explosives, acids, or any other article liable to impregnate or
            otherwise damage carrier's equipment or other property loaded in the
            carrier's van. Aerosol containers cannot be shipped.

      -     Carriers will not accept items which cannot be taken from the
            employee's premises without causing damage to the premises or to the
            item itself.

      -     Consult the carrier on items likely to fall within these exclusions.

-    INCOME TAX

      -     Moving costs paid by Caliper on behalf of an employee are not
            considered taxable income. However, these IRS Regulations are
            subject to change. Therefore, questions regarding taxable income
            should be referred to your tax consultant. Items that are determined
            by our accounting department to be taxable will be grossed up by 65
            percent.
-    NON - REIMBURSABLE EXPENSES

      -     Expenses incurred for the following items will not be reimbursed by
            Caliper Technologies Corp.:

            -     House Cleaning

            -     Removing or installing drapery rods, et cetera

            -     Transporting boats, major recreation or hobby equipment,
                  machine tools (except as noted in B. HOUSEHOLD GOODS),
                  building supplies, automobile parts, firewood, live plants,
                  wine collections and other items not usually considered
                  household furnishings
<PAGE>
            -     Dismantling gym sets or removing permanently installed gym
                  sets.

            -     Transporting or boarding of animals or livestock.

            -     Lifting or installing wall to wall carpeting

            -     Rug cleaning

            -     Hanging mirrors, pictures or other items involving special
                  charges by the carrier.

            -     Removing or installing television antennas and dishes.

            -     Expedited service or exclusive use of carrier's van.

            -     Any other services for which a carrier may assess a special
                  charge.

-    BILLING CHARGES

      -     The carrier will bill Caliper for all allowable transportation and
            packing charges incurred in relocating your household goods.

- CLOSING COSTS - SELLER

      -     Broker's commission and or sale discounts to buyer up to 6% of the
            selling price for both.

      -     Attorney's fees.

      -     Transfer fees.

      -     Title fees.

      -     Termite inspection.

      -     Property survey.

-     CLOSING COSTS - BUYER

      -     Loan origination fees, discounts, etc. not to exceed 2.0 points
            based on the loan amount.

      -     Appraisal, inspection, document preparation, tax service, express
            courier service, wire, notary fees and the like.

      -     Credit report.

      -     Title insurance, search, etc.

      -     Inspections

      -     Attorney's fees not to exceed 1% of sale price.

Requests for further information or assistance should be addressed to:

Richard Butts
Human Resources Department
605 Fairchild Drive
Mountain View, CA 94043
650 623 0520
Richard.butts@calipertech.com
<PAGE>
November 28, 2001


Susan Evans Ph.D.



Re: Addendum to offer of employment from Caliper Technologies Corp.


Dear Sue:

In addition to the terms and conditions stated in our offer of employment dated
November 13, 2001, we add the following.

 BENEFITS

      -     You will accrue vacation leave at the rate of 1.6667 days per month.

      -     At the start of your employment, your vacation leave balance will be
            set up with 10 days of leave prior to the above accrual. However,
            your maximum leave accrual at the end of 2002 will be 20 days.

      -     It is understood and agreed that you will be taking two weeks
            vacation leave for a family vacation commitment in late April or
            early May.

RELOCATION

      -     Temporary Living As part of your relocation the company will
            reimburse you for up to six months of temporary living expenses
            covering apartment and furniture rental.

            Until your personal automobile is shipped from Lake Forest a we will
            reimburse you for the cost of a rental car. Arrangements will be
            made to ship your automobile shortly after the start of employment.
            Upon your start of e or transportation of my personal vehicle to the
            area.

      -     House Hunting Travel

            The company will arrange for air transportation for your husband to
            travel from Chicago to San Francisco for the purpose of two (if
            needed) house hunting.

      -     Trips to Lake Forest, Illinois

            If needed, the company will reimburse you for the cost air
            transportation to and from your home in Lake Forest until your home
            is sold and your husband has relocated to the San Francisco Bay
            Area. This is limited to one trip per month for up to six months.

      -     Moving Expenses

            We are waiving the household goods weight limit.

            If an additional cost is incurred for the use of secondary moving
            trucks due to access restrictions to your new house this will be
            reimbursed as part of your relocation package.
<PAGE>
Susan Evans
Employment Offer Addendum

November 28, 2001
Page two

      -     Income Tax Gross Up

            Moving costs paid by Caliper on behalf of an employee are not
            considered taxable income. However, these IRS Regulations are
            subject to change. Therefore, questions regarding taxable income
            should be referred to your tax consultant. Items that are determined
            by our accounting department to be taxable will be grossed up by 75
            percent.

      -     Duel Mortgage Protection

            Based on your taking all reasonable steps to sell your home in Lake
            Forest at a reasonable market price the company will provide
            reimbursement for the actual cost of your Lake Forest mortgage and
            property taxes for up to three months following the start of any
            mortgage commitment for a primary residence in the San Francisco Bay
            Area. The maximum for this protection is capped at $3,500 per month.

SEVERANCE

      If your employment with Caliper Technologies Corp. is terminated
      involuntarily within 12 month of the start of your employment severance
      payments are agreed as follows: Termination for Cause, No severance;
      Constructive discharge or involuntary termination, base salary for 12
      months or until you are employed by another company as a regular employee
      or consultant, whichever is less. If your termination is connected with a
      change of control, severance payments will be as stated in your original
      offer letter.

START DATE

      As I am sure you are aware we are anxious for you to join our team.
      However, we recognize issue of completing the work you have started, the
      holidays and the economics of leaving your current employer just prior to
      qualification for your bonus. We could agree with a start date of February
      4, 2002 if you would be amenable to reviewing some background, planning
      and project information under Confidentiality Agreement prior to this
      start date.

If you have any questions regarding this addendum please contact Richard Butts
or myself. Once again, we believe your addition to our management team will
great for you and Caliper Technologies.

Regards,

/s/ Daniel L. Kisner
-----------------------
Daniel L. Kisner, M.D.
Chief Executive Officer & President



Accepted:  /s/ Sue Evans                      Date: 12/13/01
          --------------------------------    ----------------------------------