Rapid Detection of Transition Metals in Welding Fumes Using Paper-Based Analytical Devices

Abstract

Metals in particulate matter (PM) are considered a driving factor for many pathologies. Despite the hazards associated with particulate metals, personal exposures for at-risk workers are rarely assessed due to the cost and effort associated with monitoring. As a result, routine exposure assessments are performed for only a small fraction of the exposed workforce. The objective of this research was to evaluate a relatively new technology, microfluidic paper-based analytical devices (µPADs), for measuring the metals content in welding fumes. Fumes from three common welding techniques (shielded metal arc, metal inert gas, and tungsten inert gas welding) were sampled in two welding shops. Concentrations of acid-extractable Fe, Cu, Ni, and Cr were measured and independently verified using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results from the µPAD sensors agreed well with ICP-OES analysis; the two methods gave statistically similar results in >80% of the samples analyzed. Analytical costs for the µPAD technique were ~50 times lower than market-rate costs with ICP-OES. Further, the µPAD method was capable of providing same-day results (as opposed several weeks for ICP laboratory analysis). Results of this work suggest that µPAD sensors are a viable, yet inexpensive alternative to traditional analytic methods for transition metals in welding fume PM. These sensors have potential to enable substantially higher levels of hazard surveillance for a given resource cost, especially in resource-limited environments.

Speciation of chromium in water samples using microfluidic paper-based analytical devices with online oxidation of trivalent chromium

“…Several research groups have reported the colorimetric detection of Cr(VI) using μ-PADs based on the specific reaction with 1,5-diphenylcarbazide (DPC) [27][28][29][30][31][32][33][34]. In early studies, Rattanarat et al and Cate et al used an online oxidation reaction with Ce(IV) to present colorimetric measurements of total Cr [30,31]. We also demonstrated a remote investigation of total Cr in environmental samples from Ethiopia using μ-PADs [32].…”

“…When the solution reached the detection zones by capillary action, the immediate appearance of a purple color was visible to the naked eye. The original amount of Cr(VI) reacted with 1,5-DPC to form a colored complex in the left channels [31,37,38] whereas the total Cr(IV), which included additional Cr(VI) that originated from the online oxidation of Cr(III) by Ce(IV), produced a purple color in the right channels.…”

“…Microfluidic paper-based analytical devices (μ-PADs) have tremendous potential to address the demands for simplicity, expeditiousness, portability, and easy operation that will permit use in remote areas and developing countries [26]. Several research groups have reported the colorimetric detection of Cr(VI) using μ-PADs based on the specific reaction with 1,5-diphenylcarbazide (DPC) [27][28][29][30][31][32][33][34]. In early studies, Rattanarat et al and Cate et al used an online oxidation reaction with Ce(IV) to present colorimetric measurements of total Cr [30,31].…”

Microfluidic Paper-Based Analytical Devices: From Design to Applications

“…With paper-based devices, samples can be tested closer to or at the site of contamination, reducing the cost and time associated with heavy metal detection. For example, sample digestion can be performed on a filter membrane with nitric acid and a low-power microwave . Using this digestion method, sample has been analyzed colorimetrically, − electrochemically, and by distance .…”

“…For example, sample digestion can be performed on a filter membrane with nitric acid and a low-power microwave . Using this digestion method, sample has been analyzed colorimetrically, − electrochemically, and by distance . Pretreatment zones are often incorporated directly into devices as well.…”