New Fabric A

Fabric A rinsed, sit

3 days

Fabric A rinsed, left

for 2 weeks

Polypropylene

signal

Insecticide B

signal

William J. Gabler, Chandler Probert, Tyler Pickett, R. Bryan Ormond

Measuring Transfer from

Insecticide Treated Textiles

1. Hayes, D. g. in Functional Textiles for Improved Performance, Protection, and Health (eds. Pan, N. & Sun, G.) 404–433 (Woodhead Publishing Limited, 2011).2. Clausen, P. A. et al. Experimental estimation of migration and transfer of organic substances from consumer articles to cotton wipes: Evaluation of underlying mechanisms. J. Expo. Sci. Environ. Epidemiol. 26, 104–12 (2016).3. Ivancic, W. A. et al. Development and evaluation of a quantitative video-fluorescence imaging system and fluorescent tracer for measuring transfer of pesticide residues from surfaces to hands with repeated contacts. Ann. Occup. Hyg. 48, 519–532 (2004).

Theory/assumptions3:

• Insecticide on the surface of the polymer, Cs, exists in equilibrium

with the bulk concentration in the polymer, Co

• Transfer from the polymer to a contact surface occurs by:

• Mechanical transfer to the other surface

• Chemical attraction to the other surface

• Diffusive transfer over extended contact times, D

• A characteristic transfer efficiency exists for a contact

surface/wiping technique: Tr = Mrecovered/Msurface

• Insecticide migrates in the polymer based on Fick’s laws

Surface AnalysisTime-of-Flight Selected Ion Mass Spectrometry (TOF/SIMS) provides spatial

concentration on surface by bombarding with ion beam and detecting the

abundance of characteristic mass fragments. Possible to validate findings or detect

lower quantities?

Insecticidal TextilesInsecticide treated textiles are important tools for controlling the transmission

of infectious disease by insects around the world. Some fabrics are created with

the insecticide incorporated into the fiber polymer so reapplication is not

necessary and distribution/implementation is simpler. These textiles are

preferred over residual spraying techniques for vector control in certain

applications. The textiles have a layer of insecticide on the surface which is

replaced from the bulk of the polymer over time.1

Manufacturers want to know:

What is the surface concentration?

How much transfer occurs from contact with the textiles?

What is the effect of different cleaning methods on the concentration of

the surface and performance of the product?

Three different

non-halogenated

insecticides were

investigated,

identified as:

Future Work• Need to combine wipe transfer values with diffusion and fiber dimensions to estimate

rate - develop predictive model of transfer and recovery• Compare different washing/treatments– detergents, environmental ageing,

contaminants, and field-deployed samples etc. – effect on Cs• Expand TOF/SIMS work to monitor sample in different conditions• Explore other contact sampler materials• Correlate surface concentration values with bioefficacy• Incorporate findings into improved product design and information for users

Diffusion from the pellets to an extraction solution were modeled by sorption/desorption

equation for a sphere. Concentration over time of pellets submerged in acetone (solubility

in water was too low – showed no diffusion) – providing an (over)estimation of diffusion

rate.

Extraction and Chemical AnalysisBulk extraction using Buchi Speed Extractor E-916 Pressurized Fluid Extractor

(PSE). Methods verified by performing cycles to exhaustion on ~200 mg samples.

Fabric – 80°C, 100 barr, 10 mL cell, 15-20mL acetone, 1 cycle, 10 minute hold.

Pellets – 135°C, 100 barr, 10 mL cell, 45-60 mL acetone total, 3 cycles, 30 min holdDetection – All analysis performed on Agilent Infinity 1260 HPLC, Poroshell 2.7

μm C18 column, ACN/H2O solvent, with a Diode Array Detector monitoring

absorbance wavelength for each insecticide. Based on 6-point calibrationsbetween 0.05 and 150 μg/mL. Limits of quantitation on the order of 0.5 μg/mL in

acetone.

Surface Transfer and Wipe Experiments

Wipe ExperimentsCharacterize transfer by measuring recovery from a

spiked surface and from fabrics using different wipes

• Cellulosic wipe (KW)– absorbing wipes, low

extractables –represent cotton and paper

• C18 - solid phase extraction disk, oleophilic surface –

intended to represent oily skin

Conditions:

• Dry (D) – no solvent

• Water (W) – typical cleaning solution

• Acetone (A) - solvent in which insecticides have high

solubility

Insecticide Molar Weight log (Kow)Water Solubility (mg/L)

at ~20°C, pH 7

A 873.1 3.99 <0.01

B 421.5 5.01 0.023

C 306.4 5.71 0.102

Fabric / Insecticide

Basis Weight (g/m2)

Mass Content (%)

ArealContent (average ug/cm2)

FiberDiameter

(μm)

Cs, Surface Conc.

(ug/cm2

estimated)*

Fabric 1AB

104 ± 13

0.06 ±0.0050.35 ±0.005

6.236.4

32 ± 1.5

0.710.6

Fabric 2AC

0.060.35

6.236.4

0.96.23

𝑀𝑡

𝑀∞=6

𝑟√𝐷𝑡

𝜋

± = 95% CI *Mass extracted per gram of fabric from surface <5 sec solvent rinse of the fabric, converted to cm2 using basis weight

} Tr

𝑀𝑡 = 𝑚𝑎𝑠𝑠 𝑑𝑖𝑓𝑓𝑢𝑠𝑒𝑑 𝑎𝑡 𝑡𝑖𝑚𝑒 𝑡𝑀∞= 𝑡𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑖𝑛 𝑝𝑒𝑙𝑙𝑒𝑡𝑠r = radius, cm (average pellet dimensions)D = diffusion coefficient, cm2/sec

D (cm2/s)

A 1.94E-12

B 1.73E-10

C 4.88E-09

Example 5-cm diameter fabric swatch containing insecticide A and B, cut for extraction and contact sampling

Example ~3mm polymer pellets containing 17% insecticide B by weight

Products were provided by

Vestergaard Frandsen: Two

polypropylene spunbond

nonwovens, manufactured

from insecticide impregnated

pellets. Concentrations

verified using bulk extraction:

Pellet A – 9% by weight,

Pellet B – 17% by weight,

Pellet C – 14% by weight.

Diffusion Transfer Rates

Key Findings

• Insecticide is not evenly distributed on surface.

• Little insecticide is detectable 3 days after samples

were rinsed with water, but after 2 weeks the

insecticide appears to have returned in a new

distribution pattern on the surface.

• Insecticide A did not have a strong enough response

for analysis

Metal cylinder – 5-6 kPa (~0.8 psi)

Dry or wetted sampler

Insecticide treated surface or fabric

Static for long duration or active sampling (dragging) across fabric in order to sample larger surface area. Sampler removed and extracted with acetone then analyzed to determine transferred mass.

% recovered, Tr, from a spiked hard surface

What affects transferred amount? Pressure, contact area, duration, solubility, migration rate

Contact area of hands pressed on metal surfaceIvancic, et al. 4

• Wetted cellulosic wipe provided highest mass removal

• A water wipe gives higher transfer than solubility limit allows – mechanical

transfer enhanced by wet wipe, performs as well as acetone wipe

• Static wet sampling appears to provide similar transfer to active wipe – both

remove <10% of estimated Cs (only one side of fabric sampled)

• C18 samplers had low recoveries – sampler surface may be too fragile

• Orders of magnitude differences in D unexpected

• Diffusion rates attained could be used to predict rate of regeneration of insecticide – more work required

1psi –76cm2

0.1psi –54cm2

1psi smudge – 146cm2

μg/cm2 of insecticide B recovered from static cellulosic wipe + water over time of Fabric 1

μ g/cm2 of insecticide B recovered from active cellulosic wipe + water repeated on same fabric

μ g/cm2 recovered from active wipe both fabrics using different samplers

Acknowledgements: Research funded by Vestergaard Frandsen

Approaches cumulative mass

of ~ 1 μ g/cm2

Approaches cumulative mass of

~ 1.75 μ g/cm2

Insecticide B in pellet – exists in localized concentrated regions

𝑀𝑡

𝐴= 2 ∗ 𝐶𝑜 𝐷 ∗ 𝑡/𝜋

Regeneration

initially modeled

with simplified

equation for

diffusion from a

cylinder. Greatlyoverestimated rate.

𝐴 = 𝑎𝑟𝑒𝑎 𝑢𝑠𝑒𝑑 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑓𝑎𝑏𝑟𝑖𝑐 𝑛𝑜𝑡 𝑎𝑐𝑡𝑢𝑎𝑙 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑓𝑖𝑏𝑒𝑟 𝑠𝑢𝑟𝑓𝑎𝑐𝑒𝐶𝑜= 𝑏𝑢𝑙𝑘 𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛, 𝑢𝑔/𝑐𝑚3 estimated from typical density of polypropylene

A and B on dry wipes were detected but below method LOQ = of 0.004 ug/cm2

A and B on dry wipes were detected but below method LOQ = of 5% recovery

Textile Protection and

Comfort Center (TPACC)