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Solid-Phase Extraction Coupled to a Paper-Based Technique for Trace Copper in Drinking Water Casey W. Quinn, David Cate, Daniel Miller-Lionberg, Thomas Reilly, John Volckens, and Charles S. Henry Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b05436 • Publication Date (Web): 22 Feb 2018 Downloaded from http://pubs.acs.org on February 22, 2018

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Environmental Science & Technology

Solid-Phase Extraction Coupled to a Paper-Based Technique for Trace Copper in Drinking Water Casey W. Quinn†, David M. Cate‡, Daniel D. Miller-Lionberg║, Thomas Reilly III║, John Volckens*†§, and Charles S. Henry*‡┴ # †Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA; ‡School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA; §Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA; ║Access Sensor Technologies, LLC, Fort Collins, Colorado 80524, USA; ┴ Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA; #Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, Colorado 80523, USA 1

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ABSTRACT

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Metal contamination of natural and drinking water systems poses hazards to public and

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environmental health. Quantifying metal concentrations in water typically requires sample

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collection in the field followed by expensive laboratory analysis that can take days to weeks to

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obtain results. The objective of this work was to develop a low-cost, field-deployable method to

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quantify

trace

levels

of

copper

in

drinking

water

by

coupling

solid-phase

10

extraction/preconcentration with a microfluidic paper-based analytical device. This method has

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the advantages of being hand-powered (instrument-free) and using a simple ‘read by eye’

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quantification motif (based on color distance). Tap water samples collected across Fort Collins,

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CO were tested with this method and validated against ICP-MS. We demonstrate the ability to

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quantify the copper content of tap-water within 30% of a reference technique at levels ranging

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from 20 to 500,000 ppb. The application of this technology, which should be sufficient as a rapid

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screening tool, can lead to faster, more cost-effective detection of soluble metals in water

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systems.

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INTRODUCTION

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Recent municipal1 and environmental2 water contamination events have highlighted public

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health concerns regarding water quality. Events like those in Flint, MI and the Gold King Mine

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in Colorado have produced considerable outrage3,

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improved monitoring.5 Affected stakeholders have placed particular emphasis on increasing the

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spatial and temporal resolution of monitoring, in an effort to promote more effective risk

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communication (and control efforts) during a contamination event.6,

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methods for trace metals analysis, however, rely on expensive equipment and time-intensive

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procedures. Therefore, a need exists for water quality monitoring methods that are rapid, low-

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cost, and scalable to the needs not only of regulatory agencies but also the general public.

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and have increased public demand for

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Standard reference

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Microfluidic paper analytical devices (µPADs) represent an emerging technology platform that

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shows promise for scalable, low-cost monitoring of water quality. Most µPAD applications have

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focused on medical diagnostics,8-10 but this technology is also well poised to make advances in

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environmental monitoring.11 The present work focuses on µPAD detection of Cu in drinking

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water. Although low-levels of Cu intake are essential for human and aquatic health, high levels

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of intake can be toxic.12,

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monitoring of Cu in drinking water under the 1991 Copper and Lead rule14 and also under the

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National Recommended Aquatic Life Criteria.15 The current EPA Action Level (concentration

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that when exceeded warrants remedial action) for Cu in drinking water is 1.3 ppm.16 Although

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colorimetric intensity17-26 and distance-based27-28 µPADs have been developed for Cu, these

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existing designs have limitations. Intensity-based µPADs require the evaluation of the color hue

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and/or intensity, which can be difficult to access accurately without the aid of imaging

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equipment and software. Distance-based µPADs are easier to evaluate in the field as they can be

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The U.S. Environmental Protection Agency (EPA) requires


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read by eye; however, such methods, to date, cannot detect Cu concentrations at or below the

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EPA limit of 1.3 ppm.

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Solid-phase extraction of metal ions has been previously demonstrated as a sample preparation

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technique for Flame Atomic Absorption Spectrometry,29-31 X-Ray Fluorescence,32,

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Reflectance Spectroscopy,34-36 and for intensity-based µPADs.37 In this work, EmporeTM

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chelation disks were used to extract the metal ions from the sample to reduce the potential for

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interferences from sample matrix effects and to preconcentrate Cu from tap water samples for

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subsequent quantification using a distance-based µPAD. While we focused on Cu, the method

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has broad utility to other types of analytes.38 Once captured, the Cu was extracted from the disk

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with 100 µL of acid and eluted onto a distance-based µPAD for direct quantification. Using this

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approach, a detection limit of 20 ppb was achieved, approximately two orders of magnitude

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lower than methods without preconcentration. Finally, Cu levels were measured in drinking

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water from multiple sites and gave good agreement for paired samples analyzed by ICP-MS.

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EXPERIMENTAL METHODS

Diffuse

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Chemicals. Ultrapure water (18.2 MΩcm) from a Mill-Q system was used for the preparation

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of solutions and cleaning of supplies and equipment (Merck Millipore, Darmstadt, Germany).

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Analytical-grade chemical reagents were used. Copper(II) sulfate pentahydrate, dithiooxamide

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(98.5%), and hydroxylamine hydrochloride were purchased from Sigma-Aldrich (St. Louis, MO,

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USA). Sodium acetate, nitric acid, sodium hydroxide, glacial acetic acid, and isopropanol were

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obtained from Fisher Scientific (Pittsburgh, PA, USA).

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µPAD Fabrication. The distance-based µPAD design39 and dithiooxamide Cu detection ink

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reported by Cate et. al.27 were leveraged in this work. The µPAD was created on Whatman


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(grade 4) filter paper (GE Healthcare Bio-Sciences, Pittsburgh, PA, USA) using a red wax

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barrier to enhance visibility of the colorimetric product. The distance-based µPAD design is

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shown in the supporting materials (Figure S1). In brief, red wax barriers (46 devices per 8”x11”

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sheet) were printed on filter paper using a wax printer (Xerox ColorQube 8860). Next, a

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piezoelectric ink-jet printer (Epson R280) deposited the dithiooxamide reagent along the flow

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channel according to a pre-determined gradient (five printing cycles in all) with more reagent

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deposited near the sample addition zone and decreasing amounts of reagent along the detection

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zone. The reagent gradient improves the linear response by offsetting the Lucas-Washburn40

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capillary flow as found by Cate et. al.27 For this work, dithiooxamide was printed as two

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gradients (Figure S1) in series. At the midpoint of the detection zone a second identical gradient

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was started; this second gradient provided a visible warning indication for the presence of high

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Cu concentrations (Figure S1). After printing, a 350 nL aliquot of 10%(w/w) hydroxylamine was

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pipetted onto the pretreatment zone. Next, the Whatman paper was placed inside a lamination

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sheet and passed through a laminator (Apache AL13P) six times at 340°F to melt the wax

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through the paper and to seal the device. The wax barrier and the plastic laminate sheets provide

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hydrophobic barriers to confine the sample flow within the channel and to prevent evaporation

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during analysis. A 3 mm hole was then punched into each device to form a sample addition zone;

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clear packing tape was applied to the underside of each hole creating a small reservoir for sample

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addition.

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Preconcentration and µPAD Analysis. The sample workflow for analysis of Cu is depicted

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in Figure 1. Standard solutions prepared from analytic reagents were used to calibrate the

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method.


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1 Sample Draw

2 Sample Preconcentration

3 Acid Elution

4 pH Adjustment

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6 Quantification

5 Sample Addition

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Figure 1: Schematic for sample collection, preconcentration, and µPAD analysis in six steps: 1)

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Sample water is drawn into a syringe, 2) Sample water is passed through an EmporeTM chelation

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disk for metal capture, 3) A drop of acid is passed through the EmporeTM chelation disk,

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releasing the metal ions back into solution and depositing them into a micro-centrifuge tube

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containing pre-mixed amounts of base and buffer, 4) A pH adjusted aliquot is pulled from the

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centrifuge tube 5) The aliquot is added to the distance-based µPAD, 6) After 30 min (once the

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sample has fully been wicked along the length of the µPAD), the color formation distance is read

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to determine the sample concentration.

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Sample Preconcentration. Initial development of the preconcentration technique leveraged

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work by Gazda et. al.,35 which used a polystyrene-divinylbenzene EmporeTM solid-phase

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extraction Chelation disk (3M) housed in a 13 mm Millipore Swinnex filter holder; however,

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modifications were made to optimize this technique. We used computer-aided design software

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(SolidWorks® ANSYS, Inc., Canonsburg, PA, USA) and rapid-prototype machining to develop

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a holder that is chemically resistant (made from Sabic Ultem 1000 thermoplastic) and thus,

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reusable with 10 mm chelation disks. Head space for the chelation disk was integrated into the

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upper portion of the filter holder to accommodate the swelling that occurs when the disk is


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wetted; this feature reduces the amount of backpressure during preconcentration (Figure 1 step

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2). Drain manifold tracks were added to the lower portion of the filter holder and a polyether

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ether ketone (PEEK) mesh was used to eliminate blockage of the outlet of the filter cartridge. As

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a result, the holder allows for a high acid extraction efficiency (Figure 1, step 3) with a minimal

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acid wash volume. The final preconcentration design consisted of a 10 mm punch of solid-phase

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extraction chelation disk (3M) paired with a 10 mm punch of fine woven PEEK mesh which

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were placed inside the custom holder (Figure 2).

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Copper was adsorbed to the disk by passing a 30-mL aqueous sample through the EmporeTM

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chelation disk by hand with a disposable syringe. Each 30-mL sample required approximately

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five minutes to complete the preconcentration (Figure 1, steps 1-3). Most of that time was

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attributed to the sample preconcentration (Figure 1, step 2) due to the limited flow rate of the

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chelation disk; estimated flow rates were comparable to the 3M documentation (400 ppb, n=5) were found in


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some of the oldest buildings on campus are shown in Figure 6 (orange/red dots), and are likely

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the result of old infrastructure and/or pipe corrosion.

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Figure 6: Cu concentrations by sample location. Inset shows all samples collected across Fort

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Collins (n=33) in August of 2015. The Colorado State University main campus is enclosed with

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the red dotted lines on the inset, and the samples (n=19) collected there are displayed on the main

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map. Maps were generated with the ggmap44 library using R 3.4.1 (R Core Team, Vienna,

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Austria).

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Implications for Metal Detection in Water Sources. A preconcentration technique coupled

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with a distance-based µPAD with minimal equipment requirements has been developed. This

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new method can be used for quantitative detection of Cu at parts-per-billion levels in water and

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has been validated against ICP-MS. Although both qualitative and quantitative colorimetric kits


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for Cu detection are commercially available (in addition to aforementioned laboratory methods),

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the distance-based measurement described here offers several key advantages. For example,

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distance-based detection is more precise than existing low-cost methods that rely on color chart

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comparisons.48 Although a single measurement is limited to a smaller range of concentrations

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(e.g. 20-375 ppb when using a 188× preconcentration factor), one can adapt the method to

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measure a wide range of Cu concentrations (from approximately 20 to 500,000 ppb) by adjusting

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the volume of sample that is preconcentrated and/or adjusting the aliquot volume that is added to

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the µPAD.

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The implementation of a second gradient along the µPAD detection region provides a warning

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indicator that the optimal detection range has been exceeded (Figure 3); this line also may be

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used to alert a user that Cu concentrations have reached or exceeded action limits. Finally, the

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output from the µPAD can be easily captured using a smartphone for long-term data storage, the

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advantages of which have been described in a number of reports.49-57 A phone application similar

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to these could be developed to measure the length of the color formation and automatically

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report that data back to a central data server. Adding this functionality would allow the

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image/results to be quickly relayed back to a central location.

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There are several limitations worth noting. 1) The color formation produced by the Cu-

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dithiooxamide complex is relatively faint especially when Cu concentrations are low (Figure 3).

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The use of another complexing reagent with higher molar absorptivity would improve

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readability. Bathocuproine has been successfully used in µPADs for the detection of Cu;22

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however, the development of a bathocuproine ink compatible with an ink-jet printer has yet to be

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developed. Silver nanoparticles (AgNP) have been used with traditional µPADs to detect ppb

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levels of Cu.23 The use of AgNP could be a potential candidate for future work and improve the


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sensitivity of the method; however, deposition of the AgNP on the µPAD and immobilization of

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the Cu-AgNP complex would need to be considered. Recent work has successfully demonstrated

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the use of Meso-tetrakis(1,2-dimethylpyrazolium-4-yl)porphyrin sulfonate (TDMPzP), a water-

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soluble porphyrin derivative for Cu detection using a distance-based µPAD.28 The TDMPzP

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ligand provides a very visible response to Cu and future work will likely try to couple this µPAD

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motif with the preconcentration technique to quantify ppb Cu in water. 2) The distance-based

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µPAD demonstrated in this work required 30 minutes to complete sample wicking and color

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formation. The Cu-TDMPzP color formation will help reduce the quantification time by

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providing a distinct color formation. Work is also underway to reduce the time to transport the

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sample aliquot along the length of the µPAD measurement zone. 3) Currently Cu is the only

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analyte that has been evaluated with this method; however, there is potential to extend this

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method to other metals. For example, colorimetric reagents have been described for arsenic,58

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chromium,17 nitrate/nitrite,59 and lead,37 all of which are regulated in drinking water by the U.S.

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Environmental Protection Agency.

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The preconcentration-µPAD system has the potential to provide water quality experts,

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technicians, and other stakeholders with a tool that can provide quick and inexpensive analysis of

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a large number of water samples. This method will not eliminate the need for standard laboratory

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sample analysis; however, this method can be used for the identification of a pollutant source in

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a river section, provide spatial-temporal feedback during accidental events (similar to the Gold

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King Mine incident), or provide municipalities with a cost-effective means to implement a

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monitoring network without a substantial investment of resources.

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ASSOCIATED CONTENT


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Supporting Information.

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The following file is available free of charge.

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One 16-page PDF document containing 4 figures, 1 equation, 8 tables, and 1 method.

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AUTHOR INFORMATION

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Corresponding Authors

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*Phone: 1-970-491-2852. Fax: 1-970-491-1801. E-mail: [email protected] (C.S.H.).

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Phone: 1-970-491-6341. E-mail:[email protected] (J.V.).

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ORCID

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Charles S. Henry: 0000-0002-8671-7728

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Casey W. Quinn: 0000-0002-6802-5250

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Notes

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The authors declare no competing financial interest.

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ACKNOWLEDGMENT

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This work was supported by grant 1415655 from the National Science Foundation and a State of

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Colorado Advanced Industries Grant. The authors wish to thank all of the volunteers whom

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provided water samples from their homes.

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REFERENCES

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1. Butler, L. J.; Scammell, M. K.; Benson, E. B., The Flint, Michigan, Water Crisis: A Case Study in Regulatory Failure and Environmental Injustice. Environmental Justice 2016, 9, (4), 9397. 2. Emergency Response to August 2015 Release from Gold King Mine. http://www.epa.gov/goldkingmine (accessed Jan. 2018), 3. Rodriguez-Freire, L.; Avasarala, S.; Ali, A.-M. S.; Agnew, D.; Hoover, J. H.; Artyushkova, K.; Latta, D. E.; Peterson, E. J.; Lewis, J.; Crossey, L. J.; Brearley, A. J.; Cerrato,


17


307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351

Page 18 of 21

J. M., Post Gold King Mine Spill Investigation of Metal Stability in Water and Sediments of the Animas River Watershed. Environmental Science & Technology 2016, 50, (21), 11539-11548. 4. Bellinger, D. C., Lead Contamination in Flint — An Abject Failure to Protect Public Health. New England Journal of Medicine 2016, 374, (12), 1101-1103. 5. Rutt, R. L.; Bluwstein, J., Quests for Justice and Mechanisms of Suppression in Flint, Michigan. Environmental Justice 2017, 10, (2), 27-35. 6. Scully, J. R., The Corrosion Crisis in Flint, Michigan: A Call for Improvements in Technology. The Bridge of the National Academy of Engineering 2016, 46, (2), 9-29. 7. Drinking Water Action Plan; United States Environmental Protection Agency: Washington D.C., 2016. 8. Yang, Y.; Noviana, E.; Nguyen, M. P.; Geiss, B. J.; Dandy, D. S.; Henry, C. S., PaperBased Microfluidic Devices: Emerging Themes and Applications. Analytical Chemistry 2017, 89, (1), 71-91. 9. Cate, D. M.; Adkins, J. A.; Mettakoonpitak, J.; Henry, C. S., Recent developments in paper-based microfluidic devices. Anal Chem 2015, 87, (1), 19-41. 10. Yetisen, A. K.; Akram, M. S.; Lowe, C. R., Paper-based microfluidic point-of-care diagnostic devices. Lab Chip 2013, 13, (12), 2210-51. 11. Meredith, N. A.; Quinn, C.; Cate, D. M.; Reilly, T. H., 3rd; Volckens, J.; Henry, C. S., Paper-based analytical devices for environmental analysis. Analyst 2016, 141, (6), 1874-87. 12. Council, N. R., Copper in Drinking Water. The National Academies Press: Washington, DC, 2000; p 162. 13. Dorsey, A.; Ingerman, L. Toxicological Profile for Copper; United States Department of Health and Human Services: Atlanta, GA, 2004. 14. Lead and Copper Rule. https://www.epa.gov/dwreginfo/lead-and-copper-rule (accessed Jan. 2018), 15. Aquatic Life Criteria. https://www.epa.gov/wqc/national-recommended-water-qualitycriteria-aquatic-life-criteria-table (accessed Jan. 2018), 16. Drinking Water Contaminants. http://water.epa.gov/drink/contaminants/ (accessed Jan. 2018), 17. Cate, D. M.; Nanthasurasak, P.; Riwkulkajorn, P.; L’Orange, C.; Henry, C. S.; Volckens, J., Rapid Detection of Transition Metals in Welding Fumes Using Paper-Based Analytical Devices. Annals of occupational hygiene 2014, 58, (4), 413-423. 18. Chaiyo, S.; Siangproh, W.; Apilux, A.; Chailapakul, O., Highly selective and sensitive paper-based colorimetric sensor using thiosulfate catalytic etching of silver nanoplates for trace determination of copper ions. Analytica chimica acta 2015, 866, 75-83. 19. Hossain, S. Z.; Brennan, J. D., β-Galactosidase-based colorimetric paper sensor for determination of heavy metals. Analytical chemistry 2011, 83, (22), 8772-8778. 20. Jayawardane, B. M.; Cattrall, R. W.; Kolev, S. D., The use of a polymer inclusion membrane in a paper-based sensor for the selective determination of Cu (II). Analytica chimica acta 2013, 803, 106-112. 21. Li, M.; Cao, R.; Nilghaz, A.; Guan, L.; Zhang, X.; Shen, W., “Periodic-Table-Style” Paper Device for Monitoring Heavy Metals in Water. Analytical chemistry 2015, 87, (5), 25552559. 22. Mentele, M. M.; Cunningham, J.; Koehler, K.; Volckens, J.; Henry, C. S., Microfluidic paper-based analytical device for particulate metals. Anal Chem 2012, 84, (10), 4474-80.


18

Page 19 of 21

352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396


23. Ratnarathorn, N.; Chailapakul, O.; Henry, C. S.; Dungchai, W., Simple silver nanoparticle colorimetric sensing for copper by paper-based devices. Talanta 2012, 99, 552-557. 24. Rattanarat, P.; Dungchai, W.; Cate, D.; Volckens, J.; Chailapakul, O.; Henry, C. S., Multilayer paper-based device for colorimetric and electrochemical quantification of metals. Analytical chemistry 2014, 86, (7), 3555-3562. 25. Sadollahkhani, A.; Hatamie, A.; Nur, O.; Willander, M.; Zargar, B.; Kazeminezhad, I., Colorimetric disposable paper coated with ZnO@ ZnS core–shell nanoparticles for detection of copper ions in aqueous solutions. ACS applied materials & interfaces 2014, 6, (20), 1769417701. 26. Liu, L.; Lin, H., Paper-Based Colorimetric Array Test Strip for Selective and Semiquantitative Multi-Ion Analysis: Simultaneous Detection of Hg2+, Ag+, and Cu2+. Analytical Chemistry 2014, 86, (17), 8829-8834. 27. Cate, D. M.; Noblitt, S. D.; Volckens, J.; Henry, C. S., Multiplexed paper analytical device for quantification of metals using distance-based detection. Lab on a Chip 2015, 15, (13), 2808-2818. 28. Pratiwi, R.; Nguyen, M. P.; Ibrahim, S.; Yoshioka, N.; Henry, C. S.; Tjahjono, D. H., A selective distance-based paper analytical device for copper(II) determination using a porphyrin derivative. Talanta 2017, 174, 493-499. 29. Saxena, R.; Meena, P. L.; Tiwari, S., Determination of copper in industrial water by innovative flow injection flame atomic absorption spectrometry. Instrumentation Science & Technology 2016, 44, (2), 210-222. 30. Díaz-de Alba, M.; Galindo-Riaño, M. D.; García-Vargas, M., Solid phase extraction of copper traces using poly(styrene-divinylbenzene) membrane disks modified with pyridoxal salicyloylhydrazone in water samples. Talanta 2012, 100, 432-438. 31. Baytak, S.; Kasumov, V. T., Preconcentration and Determination of Copper (II) by Novel Solid-Phase Extraction and High-Resolution Continuum Source Flame Atomic Absorption Spectrometry. Analytical Letters 2017, 50, (1), 105-116. 32. Abe, W.; Isaka, S.; Koike, Y.; Nakano, K.; Fujita, K.; Nakamura, T., X‐ray fluorescence analysis of trace metals in environmental water using preconcentration with an iminodiacetate extraction disk. X‐Ray Spectrometry 2006, 35, (3), 184-189. 33. Hou, X.; Peters, H. L.; Yang, Z.; Wagner, K. A.; Batchelor, J. D.; Daniel, M. M.; Jones, B. T., Determination of trace metals in drinking water using solid-phase extraction disks and Xray fluorescence spectrometry. Applied spectroscopy 2003, 57, (3), 338-342. 34. Fritz, J. S.; Arena, M. P.; Steiner, S. A.; Porter, M. D., Rapid determination of ions by combined solid-phase extraction–diffuse reflectance spectroscopy. Journal of Chromatography A 2003, 997, (1), 41-50. 35. Gazda, D. B.; Fritz, J. S.; Porter, M. D., Determination of nickel (II) as the nickel dimethylglyoxime complex using colorimetric solid phase extraction. Analytica Chimica Acta 2004, 508, (1), 53-59. 36. Gazda, D. B.; Fritz, J. S.; Porter, M. D., Multiplexed colorimetric solid-phase extraction: determination of silver (I), nickel (II), and sample pH. Analytical chemistry 2004, 76, (16), 48814887. 37. Satarpai, T.; Shiowatana, J.; Siripinyanond, A., Paper-based analytical device for sampling, on-site preconcentration and detection of ppb lead in water. Talanta 2016, 154, 504510.


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38. Souza-Silva, É. A.; Jiang, R.; Rodríguez-Lafuente, A.; Gionfriddo, E.; Pawliszyn, J., A critical review of the state of the art of solid-phase microextraction of complex matrices I. Environmental analysis. TrAC Trends in Analytical Chemistry 2015, 71, 224-235. 39. Cate, D. M.; Dungchai, W.; Cunningham, J. C.; Volckens, J.; Henry, C. S., Simple, distance-based measurement for paper analytical devices. Lab on a Chip 2013, 13, (12), 23972404. 40. Washburn, E. W., Phys. Rev 1921, 17, 273. 41. Empore™ Solid Phase Extraction Disks - Technical Information; Chelating - 6208HB 98-0504-1677-9; 3M: Eagan, MN, 2009. 42. Soylak, M.; Erdogan, N. D., Copper (II)–rubeanic acid coprecipitation system for separation–preconcentration of trace metal ions in environmental samples for their flame atomic absorption spectrometric determinations. Journal of hazardous materials 2006, 137, (2), 10351041. 43. Jacobs, W. D.; H. Yoe, J., Simultaneous spectrophotometric determination of traces of cobalt, nickel and copper with dithio-oxamide. Analytica Chimica Acta 1959, 20, 332-339. 44. Kahle, D.; Wickham, H., ggmap: Spatial Visualization with ggplot2. R Journal 2013, 5, (1). 45. Noblitt, S. D.; Berg, K. E.; Cate, D. M.; Henry, C. S., Characterizing nonconstant instrumental variance in emerging miniaturized analytical techniques. Analytica Chimica Acta 2016, 915, 64-73. 46. 2016 Drinking Water Quality Report For Calendar Year 2015; Colorado State University: Fort Collins, CO, 2016. 47. 2016 Drinking Water Quality Report For Calendar Year 2015 City of Fort Collins: Fort Collins, CO, 2016. 48. HACH Copper Color Disc, 0-4 mg/L. https://www.hach.com/copper-color-disc-0-4-mgl/product?id=8276546107 (accessed Jan. 2018), 49. Chang, B.-Y., Smartphone-based Chemistry Instrumentation: Digitization of Colorimetric Measurements. Bulletin of the Korean Chemical Society 2012, 33, (2), 549-552. 50. Fronczek, C. F.; San Park, T.; Harshman, D. K.; Nicolini, A. M.; Yoon, J.-Y., Paper microfluidic extraction and direct smartphone-based identification of pathogenic nucleic acids from field and clinical samples. RSC Advances 2014, 4, (22), 11103-11110. 51. Lopez-Ruiz, N.; Curto, V. F.; Erenas, M. M.; Benito-Lopez, F.; Diamond, D.; Palma, A. J.; Capitan-Vallvey, L. F., Smartphone-based simultaneous pH and nitrite colorimetric determination for paper microfluidic devices. Anal Chem 2014, 86, (19), 9554-62. 52. Martinez, A. W.; Phillips, S. T.; Carrilho, E.; Thomas III, S. W.; Sindi, H.; Whitesides, G. M., Simple telemedicine for developing regions: camera phones and paper-based microfluidic devices for real-time, off-site diagnosis. Analytical chemistry 2008, 80, (10), 3699-3707. 53. Mudanyali, O.; Dimitrov, S.; Sikora, U.; Padmanabhan, S.; Navruz, I.; Ozcan, A., Integrated rapid-diagnostic-test reader platform on a cellphone. Lab Chip 2012, 12, (15), 267886. 54. Sicard, C.; Glen, C.; Aubie, B.; Wallace, D.; Jahanshahi-Anbuhi, S.; Pennings, K.; Daigger, G. T.; Pelton, R.; Brennan, J. D.; Filipe, C. D., Tools for water quality monitoring and mapping using paper-based sensors and cell phones. Water research 2015, 70, 360-369. 55. Thom, N. K.; Lewis, G. G.; Yeung, K.; Phillips, S. T., Quantitative Fluorescence Assays Using a Self-Powered Paper-Based Microfluidic Device and a Camera-Equipped Cellular Phone. RSC Adv 2014, 4, (3), 1334-1340.


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Page 21 of 21

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56. Wang, Y.; Ge, L.; Wang, P.; Yan, M.; Yu, J.; Ge, S., A three-dimensional origami-based immuno-biofuel cell for self-powered, low-cost, and sensitive point-of-care testing. Chem Commun (Camb) 2014, 50, (16), 1947-9. 57. Yetisen, A. K.; Martinez-Hurtado, J.; Garcia-Melendrez, A.; da Cruz Vasconcellos, F.; Lowe, C. R., A smartphone algorithm with inter-phone repeatability for the analysis of colorimetric tests. Sensors and Actuators B: Chemical 2014, 196, 156-160. 58. Nath, P.; Arun, R. K.; Chanda, N., A paper based microfluidic device for the detection of arsenic using a gold nanosensor. RSC Advances 2014, 4, (103), 59558-59561. 59. Jayawardane, B. M.; Wei, S.; McKelvie, I. D.; Kolev, S. D., Microfluidic paper-based analytical device for the determination of nitrite and nitrate. Anal Chem 2014, 86, (15), 7274-9.

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