2D wax-printed paper substrates with extended solvent supply capabilities allow enhanced ion signal in paper spray ionization

Abstract

Paper-based microfluidic channels were created from solid wax printing, and the resultant 2D wax-printed paper substrates were used for paper spray (PS) mass spectrometry (MS) analysis of small organic compounds. Controlling fluid flow at the tip of the wax-printed paper triangles enabled the use of lower spray voltages (0.5-1 kV) and extended signal lifetime (10 minutes) in PS-MS. High sensitivity (sub ng mL(-1) levels) and quantitation precision (<10% RSD) have been achieved in the analysis of illicit drugs in 4 μL of raw urine (fresh and dry), as well as corrosion inhibitors and pesticides in water samples. The reported study encourages the future development of disposable 3D microfluidic paper-based analytical devices, which function with simple operation but capable of on-chip analyte detection by MS; such a device can replace the traditional complex laboratory procedures for MS analysis to enable on-site in situ sampling with portable mass spectrometers.

Analytical Validation of a Portable Mass Spectrometer Featuring Interchangeable, Ambient Ionization Sources for High Throughput Forensic Evidence Screening

“…Ambient MS techniques [13,14], which increase sample throughput by forgoing extensive sample preparations, have shown proficiency in forensic chemical analysis [15][16][17], with recent reports involving the analysis of biofluids [18,19], explosives [20], adulterated foodstuffs [21], mind-altering plant-based evidence [22], and simultaneous molecular/elemental composition [23]. Specific techniques like desorption electrospray ionization (DESI) [24], direct analysis in real time (DART) [25], and paper spray ionization (PSI) [26,27] have shown utility in both trace and bulk drug evidence analysis, particularly in combatting the rise of Bdesigner drugs^evidence and accommodating associated paraphernalia [28].…”

Polymer‐spray mass spectrometric detection and quantitation of hydrophilic compounds and some narcotics

“…Hydrophobic materials such as polymethylmethacrylate and polytetrafluoroethylene have been shown to have enhanced signal intensity and stability over less hydrophobic materials used in desorption ionization techniques . Paper coated with a variety of different compounds has also been shown to have enhanced performance as sample support in paper‐spray mass spectrometry . We have found that hydrophobic polymer sample supports allow for the detection of hydrophilic drugs, such as streptomycin, that are not easily detected, if at all, using paper‐spray mass spectrometry.…”

“…11,12 Paper coated with a variety of different compounds has also been shown to have enhanced performance as sample support in paper-spray mass spectrometry. [13][14][15][16][17][18][19][20][21][22] We have found that hydrophobic polymer sample supports allow for the detection of hydrophilic drugs, such as streptomycin, that are not easily detected, if at all, using paper-spray mass spectrometry.…”

On‐substrate derivatization for detection of highly volatile G‐series chemical warfare agents via paper spray mass spectrometry

“…More relevantly, explosives, herbicides from aqueous matrices, pesticides, and CWA simulants from biofluids have been shown to be effectively analyzed via paper spray mass spectrometry (PS‐MS). The spray substrate has been subjected to a multitude of modifications including the addition of metal–organic‐frameworks (MOFs), carbon nanotubes, silica, urea, silanes, molecularly imprinted polymer (MIPs), and wax printing, with each resulting in a specialized system catering to a specific matrix or target chemistry. For example, these innovative modifications have allowed for sub‐parts‐per‐trillion detections of therapeutic drugs .…”