Marshall University Publications:
Abstract Recently, topical products advertising cannabinoid ingredients have gained popularity. Consumers are seeing an increase of commercial products containing ingredients from hemp oil to cannabidiol (CBD) due to health benefit claims. Cosmetic products containing cannabinoids are currently not regulated at the federal level. A laboratory experiment for undergraduate students in analytical and organic chemistry courses was developed utilizing high-performance liquid chromatography (HPLC) analysis to identify and quantify cannabinoid compounds present in commercially available topical products. Students used calibration curves of a cannabinoid standard to quantify cannabinoids present in the CBD products. By comparing relative retention times of the cannabinoids present in the standard, students were able to identify the cannabinoids present in their lotion sample. Responsibilities and assignments suit students ranging from introductory to advanced chemistry courses. Students are provided the opportunity to extract and experimentally calculate the amount of CBD and compare to the amounts advertised on product labels. Results showed that the average CBD amounts were higher than advertised for all lotions except CBDFx when analyzed using HPLC. This experiment can be modified to incorporate a variety of different topical water-based products including hair products, shampoo, and other cosmetics. Furthermore, an analysis of samples using gas chromatography mass spectrometry (GC-MS) was also developed to adapt to instrument availability
Quiñones, R.; Moreno, S.; Smythers A.L.; Sullins, C.; Pijor, H.; Brown, G. Strouten, A.; Waugh-Richards, L.; Siddig, A. “Quantification of Cannabis in Infused Consumer Products and Their Residues on Skin”, ACS Pharmacol. Transl. Sci., 2022, 5, 8, 642-651.
Abstract Cannabis consumer products are a $4.6 billion industry in the U.S. that is projected to exceed $14 billion by 2025. Despite an absence of U.S. Food and Drug Administration (FDA) regulation or clinical data, thousands of nutraceuticals, topical consumer products, and beauty products claim benefits of hemp or cannabidiol. However, a lack of required quality control measures prevents consumers from knowing the true concentration or purities of cannabis-labeled products. Thirteen over-the-counter consumer products were examined for the presence of cannabidiol (CBD), cannabinol (CBN), Δ9 - tetrahydrocannabinol (THC), cannabidiolic acid (CBDA), and Δ9 -tetrahydrocannabinolic acid A (THCA). Additionally, the efficacy of topical applications was investigated using a porcine skin model, in which particle size and zeta potential relate to skin permeability. Skin permeation was correlated to particle size and relative stability in skin-like conditions but not directly related to the CBD content, suggesting that topical products can be designed to enhance overall skin permeation. Of the products analyzed, all products have some traceable amount of cannabinoids, while seven products had multiple cannabinoids with quantifiable amounts. Overall, the need for further regulation is clear, as most products have apparent distinctions between their true and labeled contents.
Abstract Fingerprint development has been used to visualize latent prints since the 19th century, and several companies produce a variety of commercially available black fingerprint powders. While the method to develop fingerprints has been refined over the years, the composition of fingerprint powders that are used in print development has not been studied extensively. Six different black fingerprint powders were studied using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS) and zeta potential, attenuated total reflectance infrared spectroscopy (ATR-IR), Raman spectroscopy, powder X-ray diffraction (PXRD), and solution-phase nuclear magnetic resonance spectroscopy (NMR) in addition to a quality study involving certified latent print examiners. When comparing all chemical, physical, and morphological results for the fingerprint powder, this study determined that powders ranked best by latent print examiners are fingerprint powders that mainly contain carbon and oxygen with particle sizes around 50 nm and spherical morphology. Powders with large particle sizes, irregular shape, and elemental compositions consisting of many elements ranked poorly in the quality study performed.
Abstract Microwave-assisted ammonia synthesis is a promising alternative to the energy-intensive Haber-Bosch process, specially at small- and medium-scale with renewable H2 as resource. Here, we report that Cs promoted Ru/CeO2 catalyst exhibits considerable activity at 533 K and ambient pressure. In this work, the combined theoretical and experimental approaches are adopted to optimize the electronic and geometric structures of Ru on the catalysts. Both DFT modeling work and structural characterization show that the strong interaction between Ru and CeO2 results in the formation of highly dispersed Ru particles favoring ammonia synthesis. The higher electron donating ability of CeO2 and lower electronegativity of Cs promoter result in higher electron density on Ru reducing the N≡N dissociation barrier. The work demonstrates the potential of microwave-assisted catalytic process in activating stable molecules for ammonia synthesis.
Abstract With the advancements in broad-spectrum sunscreens and the recent bans on benzene-based sunscreens due to their environmental toxicity, there has been a push toward broad-spectrum sunscreens containing inorganic active ingredients. In this study, a procedure was developed to analyze the particle size and size distribution of inorganic active ingredients, titanium dioxide (TiO2) and/or zinc oxide (ZnO), of sunscreens with sun protection factor (SPF) values ranging from 15 to 50 using dynamic light scattering (DLS). These inorganic components are often engineered as nanoparticles in order to reduce visibility on the skin and retain UV scattering. Research suggests that the use of smaller nanoparticles to increase the efficacy of the inorganic filters may also be toxic to humans if it becomes permeable to the skin. This methodology allowed undergraduate students to work hands-on with particle sizing and compare sunscreen samples to nanopowder and dispersion standards using the effect of the hydrodynamic diameter. Students found that, due to agglomeration, the particle sizes for the nanopowder standards could exceed the manufacture’s labeled size when dispersed in solution, which they then compared with their sunscreen data. The results also showed that some sunscreens had two distinct layers at the end of sample preparation, which could be correlated to the matrix components within the sunscreens. This study is intended for undergraduate analytical students and can be altered using the potential variations and scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) to create a more challenging upper-level lab and allow for instrumentation comparisons.
Abstract The principal components of the 13C chemical shift tensors for the ten crystallographically distinct carbon atoms of the active pharmaceutical ingredient cimetidine Form A have been measured using the FIREMAT technique. Density functional theory (DFT) calculations of 13C and 15N magnetic shielding tensors are used to assign the 13C and 15N peaks. DFT calculations were performed on cimetidine and a training set of organic crystals using both plane-wave and cluster-based approaches. The former set of calculations allowed several structural refinement strategies to be employed, including calculations utilizing a dispersion-corrected force field that was parametrized using 13C and 15N magnetic shielding tensors. The latter set of calculations featured the use of resource-intensive hybrid-DFT methods for the calculation of magnetic shielding tensors. Calculations on structures refined using the new force-field correction result in improved values of 15N magnetic shielding tensors (as gauged by agreement with experimental chemical shift tensors), although little improvement is seen in the prediction of 13C shielding tensors. Calculations of 13C and 15N magnetic shielding tensors using hybrid functionals show better agreement with experimental values in comparison to those using GGA functionals, independent of the method of structural refinement; the shielding of carbon atoms bonded to nitrogen are especially improved using hybrid DFT methods
Abstract Melanoma, a type of cancer that develops in melanocytes, is usually caused by direct exposure of skin to ultraviolet (UV) radiation resulting in cellular damage. In this study, a procedure to determine effects of various commercial sunscreens with SPF values ranging from 15 to 100 was developed using pig skin to mimic human skin. These sunscreens contain inorganic filters, including zinc oxide and titanium dioxide, and/or active organic ingredients, such as octocrylene and oxybenzone. As a model for human skin, pig skin was analyzed before and after UV exposure and the presence of free radicals was measured using electron paramagnetic resonance (EPR) spectroscopy. Using this method, students were able to quantify the radical formation following irradiation and use this as a basis to compare the efficacy of sunscreens against UVA. This experiment allowed undergraduate students to characterize a complex chemical process (light-induced radical formation) and relate it to something they experience every day (sun damage). Interestingly, students found higher levels of post-illumination radical formation in sunscreen-treated samples, perhaps indicating sunscreen-induced stabilization of these species. Student outcomes included learning how to collect and interpret EPR data, statistical analysis of these data, and the preparation of reproducible biological samples. Students also consulted literature sources to properly display their measurements.
Abstract In this study, perfluorinated phosphonic acid modifications were utilized to modify zinc oxide (ZnO) nanoparticles because they create a more stable surface due to the electronegativity of the perfluoro head group. Specifically, 12-pentafluorophenoxydodecylphosphonic acid, 2,3,4,5,6-pentafluorobenzylphosphonic acid, and (1H,1H,2H,2H-perfluorododecyl)phosphonic acid have been used to form thin films on the nanoparticle surfaces. The modified nanoparticles were then characterized using infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state nuclear magnetic resonance spectroscopy. Dynamic light scattering and scanning electron microscopy-energy dispersive X-ray spectroscopy were utilized to determine the particle size of the nanoparticles before and after modification, and to analyze the film coverage on the ZnO surfaces, respectively. Zeta potential measurements were obtained to determine the stability of the ZnO nanoparticles. It was shown that the surface charge increased as the alkyl chain length increases. This study shows that modifying the ZnO nanoparticles with perfluorinated groups increases the stability of the phosphonic acids adsorbed on the surfaces. Thermogravimetric analysis was used to distinguish between chemically and physically bound films on the modified nanoparticles. The higher weight loss for 12-pentafluorophenoxydodecylphosphonic acid and (1H,1H,2H,2H-perfluorododecyl)phosphonic acid modifications corresponds to a higher surface concentration of the modifications, and, ideally, higher surface coverage. While previous studies have shown how phosphonic acids interact with the surfaces of ZnO, the aim of this study was to understand how the perfluorinated groups can tune the surface properties of the nanoparticles.
Abstract Solid-state nuclear magnetic resonance (SS-NMR) spectroscopy has become a common technique tostudy polymorphism in pharmaceutical solids at high-resolution. However, high-throughput applicationof high resolution SS-NMR spectroscopy is severely limited by the long1H spin-lattice relaxation (T1)that is common to solid phase compounds. Here, we demonstrate the use of paramagnetic relaxationreagents such as chromium (III) acetylacetonate (Cr(acac)3) and nickel (II) acetylacetonate (Ni(acac)2) forfast data acquisition by significantly reducing the T1value for carbamazepine Forms I, II, III, and dihydrate,cimetidine Forms A and B, nabumetone Form I, and acetaminophen Form I polymorphs. High resolution13C cross-polarization and magic angle spinning were used to measure T1values for each polymorph.In order to confirm the absence of polymorphic transitions during SS-NMR experiments, powder x-raydiffraction was implemented. The amount of chromium ions incorporated by the recrystallization processwas quantified by using inductively coupled plasma optical emission spectroscopy. Our results suggestthat the paramagnetic ions added to the polymorphs do not affect the polymorphic transformation orthe quality of NMR spectra. We believe that this successful demonstration of fast data collection willenable high-throughput utilization of SS-NMR techniques to study polymorphic solids and could set thegroundwork for NMR crystallography studies.
Abstract Nitinol (NiTi) nanoparticles are a valuable metal alloy due to many unique properties that allow for medical
applications. NiTi nanoparticles have the potential to form nanofluids, which can advance the thermal conductivity
of fluids by controlling the surface functionalization through chemical attachment of organic acids to
the surface to form self-assembled alkylphosphonate films. In this study, phosphonic functional head groups such
as 16-phosphonohexadecanoic acid, octadecylphosphonic acid, and 12-aminododecylphosphonic acid were used
to form an ordered and strongly chemically bounded film on the NiTi nanopowder. The surface of the NiTi
nanoparticles was modified in order to tailor the chemical and physical properties to the desired application. The
modified NiTi nanoparticles were characterized using infrared spectroscopy, powder X-ray diffraction, X-ray
photoelectron spectroscopy, and 31P solid-state nuclear magnetic resonance. The interfacial bonding was
identified by spectroscopic data suggesting the phosphonic head group adsorbs in a mixed bidentate/monodentate
binding motif on the NiTi nanoparticles. Dynamic light scattering and scanning electron microscopyenergy
dispersive X-ray spectroscopy revealed the particle sizes. Differential scanning calorimetry was used to
examine the phase transitions. Zeta potential determination as a function of pH was examined to investigate the
surface properties of charged nanoparticles. The influence of environmental stability of the surface modifications
was also assessed.
Abstract Polymorphism is a molecule’s ability to possess altered physical crystalline structures and has become an active interest in pharmaceuticals due to its ability to influence a drug’s physical and chemical properties.
Crystal stability and solubility are crucial in determining a drug’s pharmacokinetics and pharmacodynamics.
Changes in these properties due to polymorphisms have contributed to recalls and modifications
in industrial production. For this study, the effects of surface interactions with pharmaceuticals were
examined through surface modification methodology using organic phosphonic and sulfonic acid selfassembled
monolayers (SAMs) developed on a nickel or zinc oxide metal substrate. Drugs analyzed
included carbamazepine, cimetidine, tolfenamic acid, and flufenamic acid. All drugs were thermodynamically
applied to the reformed surface to aid in recrystallization. It was hypothesized and confirmed
that intermolecular bonds, especially hydrogen bonds between the SAMs and pharmaceutical drugs,
were the force that assisted in polymorph development. The study was successful in revealing multiple
forms for each drug, including their commercial form and at least one additional form using micro FT-IR,
Raman spectroscopy, and PXRD. Visual comparisons of crystal polymorphisms were performed with IR
microscopy.
Abstract A series of undergraduate laboratory experiments that utilize reversed-phase HPLC separation, inductively coupled plasma spectroscopy (ICP), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS)are described for the analysis of commercial sunscreens. The active ingredients of many sunscreen brands include zinc or titanium oxide in addition to organic acids. Students determine the zinc content using ICP, and the chemical composition as well as particle sizes using SEM-EDS. The organic UV absorbers octocrylene and oxybenzone are quantified using HPLC. With the incorporation of these interesting characterization techniques in second or fourth-year chemistry courses, and by having students analyze sunscreen samples that are medically relevant in terms of health effects,students engage in timely research and at the same time gain exposure to a variety of instruments in the analysis of a familiar household product.
Logan, J.L.; Quiñones, R.; Sunderland, D. "Poster Presentations: Turning a Lab of the Week into a Culminating Experience", Journal of Chemical Education, 2015, 92 (1), pp 96–101. Abstract An assignment incorporating posters into a second-year analytical chemistry lab is described. Students work in groups and are assigned one of the application-themed weekly laboratories as a topic. Course data acquired for these weekly laboratories are compiled into spreadsheets that the poster group then analyzes to present in an on-campus poster session. Visual design with the use of minimal text is emphasized, and statistical analysis and spreadsheet usage are incorporated. This assignment provides the majority of students in the course with their first poster experience. By making the students revisit a previous lab and reconsider the topic using course-wide data, a simple lab of the week becomes an in-depth project culminating in a poster presentation. Student satisfaction with this assignment has been high both in terms of group work experience and the resulting poster.
Quiñones, R.; Rodriguez, K.; Iuliucci, R. J. " Investigation of phosphonic acid surface modifications on zinc oxidenanoparticles under ambient conditions",Thin Solid Films, 2014, 564, 155 – 164.
Abstract
Zinc oxide (ZnO) nanoparticles have emerged as a fascinating metal oxide semiconductor nanomaterial due
largely to their wide array of properties that can be altered by surface modification. For example electrical and
photonic properties include a range of conductivity frommetallic to insulating (n-type and p- type conductivity),
wide-band gap semiconductivity, room-temperature ferromagnetism, and chemical-sensing. Recently there has
been much interest in the electronic and photonic properties of ZnO nanostructures as foreseeable applications
include solar cells and laser diodes. For such purposes, controlling the surface functionalization is important
and can be tailored by the chemical attachment of organic acids to the surface. The oxide surface readily reacts
with organics forming self-assembled alkylphosphonate films. In this study, ZnO nanoparticles were modified
using self-assembly thin films with phosphonic functional head groups. The amount of organic acid used in
preparation of the thin film was shown to be important to the nanoparticle surface coverage. The modified
ZnO nanoparticleswere then characterized using infrared spectroscopy, powder X-ray diffraction, solid-state nuclear
magnetic resonance, and scanning electron microscopy-energy dispersive X-ray spectroscopy. The interfacial
bonding was identified by spectroscopy analysis to be the bidentate and tridentate motifs between the
phosphonic head group and the oxide surface. Work function modification was measured using Ultraviolet
photoelectron spectroscopy. The influences of temperature, humidity, and solvent rinse on the stability of the
surface modifications were performed.
Pacilio J. E.; Tokarski, J. T.; Quiñones, R.; Iuliucci, R. J. " High-Resolution Solid-State NMR Spectroscopy: Characterization of Polymorphism in Cimetidine, a Pharmaceutical Compound", Journal of Chemical Education, 2014, 91 (8), 1236–1239.
Abstract
High-resolution solid-state NMR (SSNMR) spectroscopy has
many advantages as a tool to characterize solid-phase material that nds applications in polymer
chemistry, nanotechnology, materials science, biomolecular structure determination, and others,
including the pharmaceutical industry. The technology associated with achieving high resolution has
evolved to where SSNMR spectroscopy has become routine. To highlight SSNMR spectroscopy capability,
an experiment exploring polymorphism in a pharmaceutical compound is described. Polymorphism can be
studied by one-dimensional 13C NMR spectroscopy, presenting a straightforward experiment to
highlight the techniques of cross-polarization, magic-angle spinning, and decoupling. To aid those
unfamiliar with solid-state NMR methods, a detailed tutorial on the associated techniques is
provided. The polymorphs of cimetidine, the active pharmaceutical agent of Tagamet, were
selected to study. The development of the histamine H2-receptor antagonist was novel, and the
rational drug design approach led Sir James W. Black to share the 1988 Nobel Prize in Physiology
and Medicine. Because some of the polymorphic forms fail to produce crystals suitable for X-ray
diffraction, SSNMR spectroscopy has played a critical role in characterizing the crystal
structures of cimetidine polymorphs. The experiment has been implemented for an advanced analytical
laboratory.
Other Publications:
Roy, S.; Quiñones, R.; and Matzger, A. J. " Structural and Physicochemical Aspects of Dasatinib Hydrate and Anhydrate phases", Crystal Growth & Design, 2012, 12 (4), 2122−2126.
Abstract
Crystal structures for the commercial monohydrate form and an anhydrate form of dasatinib, an oral anticancer agent, are presented along with characterization by Raman spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. Solubility measurements conducted in water reveal that the anhydrate has dramatically improved solubility compared to the commercial hydrate form. Finally, dasatinib is a rare example of a promiscuous solvate former, and the basis for this behavior can now be understood by examining the poor packing efficiency in the unsolvated form.
Lutker, K.M.; Quiñones, R.; Xu, J.; Ramamoorthy, A. and Matzger, A. J. “Polymorphs and Hydrates of Acyclovir”, Journal of Pharmaceutical Sciences, 2010, 100 (3), 949-963. Abstract Acyclovir has been commonly used as an antiviral for decades. Although the crystal structure of the commercial form, a 3:2 acyclovir: water solvate, has been known since the 1980s, investigation into the structure of anhydrous acyclovir has been limited. Here we report characterization of 4 anhydrous forms of acyclovir and a new hydrate in addition to the known hydrate. Two of the anhydrous forms appear as small needles and are stable to air exposure, whereas the third form is morphologically similar but quickly absorbs water from the atmosphere and converts back to the commercial form. The high temperature modification is created by heating anhydrous form I above 180 °C. The crystal structure of anhydrous form I and a novel hydrate are reported for the first time. Raman, A.; Quiñones, R.; Barriger, L.; Eastman, R.; Parsi, A.; Gawalt, S. E. “Understanding Organic Film Behavior on Alloy and Metal Oxides”, Langmuir, 2010, 26 (3), 1747–1754. Abstract Native oxide surfaces of stainless steel 316L and Nitinol alloys and their constituent metal oxides, namely nickel, chromium, molybdenum, manganese, iron, and titanium, were modified with long chain organic acids to better understand organic film formation. The adhesion and stability of films of octadecylphosphonic acid, octadecylhydroxamic acid, octadecylcarboxylic acid, and octadecylsulfonic acid on these substrates were examined in this study. The films formed on these surfaces were analyzed by diffuse reflectance infrared Fourier transform spectroscopy, contact angle goniometry, atomic force microscopy, and matrix-assisted laser desorption ionization mass spectrometry. The effect of the acidity of the organic moiety and substrate composition on the film characteristics and stability is discussed. Interestingly, on the alloy surfaces, the presence of less reactive metal sites does not inhibit film formation. Lekse, J; Yao, J., Quiñones, R.; Aitken, J. A. “Synthesis, Structure and Physicochemical Characterization of a Noncentrosymmetric, Quaternary Thiostannate: EuCu2SnS4”, Journal Solid State Chemistry, (2009), 182(1), 141-146. Abstract EuCu2SnS4 was prepared by a stoichiometric combination of the elements heated to700 °C for 125 h. The structure was determined by single crystal X-ray diffraction methods. The compound crystallizes in the noncentrosymmetric, orthorhombic space group Ama2 with a ¼ 10.4793(1)Ǻ , b ¼ 10.3610(2)Ǻ , c ¼ 6.4015(1)Ǻ , Z ¼ 4, R1 ¼ 0.99% and wR2 ¼ 2.37%.The structure type is that of SrCu2GeSe4. The structure can be described as a three-dimensional network built from near perfect SnS4 and distorted CuS4 tetrahedra together with EuS8 square antiprisms. The dark red compound is a semiconductor with an optical bandgap of 1.85eV. Quiñones, R.; Gawalt, S. E. “Polystyrene Formation on Monolayer-Modified Nitinol Effectively Controls Corrosion”, Langmuir, 2008, 24(19), 10858-10864. Abstract A surface-initiated polymerization of styrene on carboxylic acid terminated phosphonic monolayers was utilized to increase the corrosion resistance of nitinol and nickel oxide surfaces. Alkyl chain ordering, organic reactions, wettability, and film quality of the monolayers and polymers were determined by infrared spectroscopy, atomic force microscopy, matrix-assisted laser desorption ionization spectrometry, and water contact angles. The polystyrene film proved to be a better corrosion barrier than phosphonic acid monolayers by analysis with cyclic voltammetry and electrochemical impedance spectroscopy. The protection efficiency of the polystyrene film on nitinol was 99.4% and the monolayer was 42%. Quiñones, R.; Raman, A. Gawalt, S. E. “Functionalization of Nickel Oxide using Alkylphosphonic Acid Self-Assembled Monolayers”, Thin Solid Films, 2008, 516(23), 8774-8781. Abstract Self-assembled monolayer formation of alkylphosphonic acids on the native nickel oxide surface has been accomplished. These monolayers are the first formed on the native nickel oxide surface that did not require electrochemical reduction of the surface to metallic nickel. Two different deposition methods, immersion and aerosol spraying, were used to form monolayers on the oxide surface. Both methods led to complete monolayer formation, with the aerosol method requiring shorter deposition time, lower temperature and decreased solution concentration compared to the immersion method. These deposition methods now allow nickel oxide substrates to be functionalized easily. Monolayer formation was investigated by diffuse reflectance Fourier transform infrared spectroscopy, non-contact mode atomic force microscopy, contact angle measurements and matrix-assisted laser desorption ionization mass spectrometry. Furthermore, cyclic voltammetry and electrochemical impedance spectroscopy studies show that the monolayer increased surface resistance to oxidation Quiñones, R.; Gawalt, S. E. “Study of the Formation of Self- Assembled Monolayers on Nitinol”, Langmuir, 2007, 23(20), 10123-10130. Abstract Shape memory alloys such as nitinol (NiTi) have gained interest due to their unique and unusual properties of thermal shape memory, superelasticity, and good damping properties. Nitinol is mainly used for medical purposes. In order to control the surface properties of this alloy, self-assembled monolayers (SAMs) were formed and characterized on the native oxide surface of nitinol for the first time. Factors which affect the formation of SAMs, such as head group functionality, chain length, and tail group functionality, were varied and analyzed. Functionalized alkyl phosphonic acid molecules (OH, COOH, and CH3) formed monolayers on the nitinol surface using a simple deposition method resulting in the molecules being ordered and strongly bound to the surface. Diffuse reflectance infrared spectroscopy (DRIFT), contact angle goniometry, atomic force microscopy (AFM), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to characterize the surfaces before and after organic modification. Quiñones, R., Raman, A. Gawalt, S. E. “An approach to differentiating between multi- and monolayers using MALDI-TOF MS”, Surface and Interface Analysis, 2007, 39 (7), 593-600. Abstract Analysis and confirmation of monolayer film thickness on metal oxide surfaces has proven to be challenging. XPS and AFM have been used to investigate the monolayer formation. However, these techniques are difficult to access and/or determine the composition of the organic molecules on the surfaces. Here we demonstrate the ability of MALDI-TOF to characterize long alkyl chain phosphonic acid molecules in thin films on titanium, iron and stainless steel. These systems are known to be stable, strongly adhered films. The thin films were characterized by IR, AFM, contact angle measurements and the results were confirmed by MALDI-TOF. Moreover, the MALDI-TOF was used to differentiate between mono- and multilayers on planar surfaces.