Sterilization Device for Liquid Sterilization Device for Liquid Chromatography SolventsChromatography Solvents

Design TeamDesign TeamNick Roulleau, Michael VoseNick Roulleau, Michael Vose

Michael Racette, Michael McKayMichael Racette, Michael McKay

AdvisorAdvisorProfessor Mohammad TaslimProfessor Mohammad Taslim

Introduction Introduction

• Background Background

• Problem StatementProblem Statement

• Past ArtPast Art

• Design RequirementsDesign Requirements

• Design ConceptsDesign Concepts

• Prototype DesignPrototype Design

• Component AnalysisComponent Analysis

• RecommendationsRecommendations

What is Liquid Chromatography?What is Liquid Chromatography?

A substance comprised of components A and B is dissolved A substance comprised of components A and B is dissolved in a solvent and enters the analytical column, where it is in a solvent and enters the analytical column, where it is separatedseparated

Basic Components of an HPLC SystemBasic Components of an HPLC System

From http://www.waters.com/WatersDivisionFrom http://www.waters.com/WatersDivision

ProblemProblem

From http://www.waters.com/WatersDivisionFrom http://www.waters.com/WatersDivision

Design GoalDesign Goal

To mitigate the risk of blockage at the To mitigate the risk of blockage at the inlet frit due to bacterial contamination inlet frit due to bacterial contamination and extend the useful life of the UPLC and extend the useful life of the UPLC column.column.

Existing SolutionsExisting Solutions

• In-line filtersIn-line filters

• Guard columns and cartridgesGuard columns and cartridges

• Pre-filtration of samples and Pre-filtration of samples and mobile phase liquidsmobile phase liquids

Product RequirementsProduct Requirements• Mandatory:Mandatory:

» Must be adaptable for use worldwideMust be adaptable for use worldwide» Must extend the useful life of columnsMust extend the useful life of columns» Must meet safety standards (ISO, UL and CE)Must meet safety standards (ISO, UL and CE)» Must operate for 1 year w/o user interventionMust operate for 1 year w/o user intervention

• Desirable:Desirable:» Should be able to filter two bottles simultaneouslyShould be able to filter two bottles simultaneously» Should meet customer acceptance criteriaShould meet customer acceptance criteria

– Low-maintenanceLow-maintenance

– Easy to use Easy to use

– CostCost

ConstraintsConstraints

• Cannot change the chemical compositionCannot change the chemical composition» Of the solventOf the solvent» Of the sampleOf the sample

• Cannot create risk of causing pump cavitationCannot create risk of causing pump cavitation

• Cannot hinder bottle accessibilityCannot hinder bottle accessibility

• Cannot negatively impact system resolutionCannot negatively impact system resolution

Initial Design ConceptsInitial Design ConceptsUV Probe

Pump/filter--External enclosure

Pump/filter--Cap enclosure

Preliminary Design – UV ProbePreliminary Design – UV Probe

• InexpensiveInexpensive

• Simple DesignSimple Design

Why Not Use Ultraviolet Radiation as a Why Not Use Ultraviolet Radiation as a Primary Solution?Primary Solution?

• Degradation of organic solvent modifiers Degradation of organic solvent modifiers (Low Risk)(Low Risk)

• Degradation of aqueous additives Degradation of aqueous additives (Low Risk)(Low Risk)

• User safety from UV-C exposure User safety from UV-C exposure (Medium Risk)(Medium Risk)

• UV can inactivate but not remove UV can inactivate but not remove bacteriabacteria

• How many bacteria could be generated per year?How many bacteria could be generated per year?

• Logarithmic growth: Logarithmic growth: » Assuming worst caseAssuming worst case

– 100% replicating100% replicating– Short generation timeShort generation time– Neglecting lag phases and cell deathNeglecting lag phases and cell death

• Filter capacity = 10Filter capacity = 107 7 CFU/cmCFU/cm22

Filter SizingFilter Sizing

Filter SizingFilter Sizing

With logarithmic bacterial growth, filter area With logarithmic bacterial growth, filter area becomes exceptionally large in a short period becomes exceptionally large in a short period

Current DesignCurrent DesignExternal Filter Enclosure with UVExternal Filter Enclosure with UV

Dual-head Dual-head

brushless DC brushless DC

pumppump

UV lamp UV lamp

with multiple with multiple

sterilization sterilization

lineslines

Pall AcroPak 200 filtersPall AcroPak 200 filters

Filter SelectionFilter Selection

• Membrane with material Membrane with material compatibilitycompatibility

• Sufficient capacity to contain 1 Sufficient capacity to contain 1 year of inactivated bacteria year of inactivated bacteria

Pump SelectionPump Selection

Micro-diaphragm pumpMicro-diaphragm pump

• Dual pump headsDual pump heads

• Ability to run dryAbility to run dry

• DC brushless motor for DC brushless motor for long lifelong life

Pump Pressure RequirementsPump Pressure Requirements

• Pump must deliver sufficient differential pressure (Δp) to move fluid through filter

• Darcy’s equation for porous media:

)(

)( 21

L

ppkAQ

Q = flow ratek = permeability constant for filterA = effective filter area (EFA)µ = viscosity

L = membrane thicknessp1 = pump-side pressurep2 = outlet pressure

UV Block Design-Initial ConceptUV Block Design-Initial Concept

UV Block DesignUV Block Design

• 99.99% inactivation requires a UV dose of at least 40 mJ/cm2 for nearly all species of bacteria

• Dose is a function of the irradiance (mW/cm2) and time of exposure (in seconds)

Dose = Irradiance x timeDose = Irradiance x time

1

1tan

1

)1(

)1(tan

2

1tan

1 11

2

121 H

H

HHY

HX

XYH

HXL

H

L

HFd

r

lL

r

hH

22)1( LHX 22)1( LHY

dA

A

UV Block DesignUV Block Design

UV Block DesignUV Block Design

13 loops necessary with an 18W UV bulb and thin wall FEP tubing13 loops necessary with an 18W UV bulb and thin wall FEP tubing

Test PlanningTest Planning

• Verification TestVerification Test

» Does the Device Meet Does the Device Meet Design Requirement?Design Requirement?

» Pump Particle-Laden Pump Particle-Laden Water from Bottles With Water from Bottles With and Without Device and Without Device

» Compare Backpressure Compare Backpressure and/or Flow Rate and/or Flow Rate

PRESSURE

0

10

20

30

40

50

60

70

80

0 100 200 300

PumpPumpDeviceDevice SensorSensor

ColumnColumn

Test ResultsTest ResultsBackpressure Test

0

2

4

6

8

10

12

1 599 1197 1795 2393 2991 3589 4187 4785 5383 5981 6579 7177 7775 8373 8971 9569 10167 10765 11363 11961

Elapsed Time (s)

Ba

ck

pre

ss

ure

(P

SI)

No Device

Device (Norm)

Backpressure was reduced by 28% when our device was usedBackpressure was reduced by 28% when our device was used

Cost AnalysisCost Analysis

• Developed target costs by estimating: Developed target costs by estimating: » Annual costs without the assistance of our device Annual costs without the assistance of our device

(excluding operational costs)(excluding operational costs)

» Savings in material costs by implementing our deviceSavings in material costs by implementing our device

• Potential savings for high-end users = $44,000Potential savings for high-end users = $44,000

• Minimum estimated annual savings = $600Minimum estimated annual savings = $600

• Target production cost = $500Target production cost = $500

• Target prototyping cost = <$1500Target prototyping cost = <$1500

Recommendations for Further Recommendations for Further DevelopmentDevelopment

• Improve manufacturability of the designImprove manufacturability of the design» Simplify tubing systemSimplify tubing system» Smaller pumpSmaller pump» Custom filter sizeCustom filter size

• Analyze effectiveness of UV with Analyze effectiveness of UV with microbiological testingmicrobiological testing

SummarySummary

• Introduction to liquid chromatographyIntroduction to liquid chromatography

• The problem and its sourceThe problem and its source

• Requirements of a good solutionRequirements of a good solution

• Design considerationsDesign considerations

• Prototype design and analysisPrototype design and analysis

• RecommendationsRecommendations

Questions???Questions???