Trifluoroacetic Acid Solution Research Articles

Process for the Purification of cis-p-Coumaric Acid by Cellulose Column Chromatography after the Treatment of the trans Isomer with Ultraviolet Irradiation.

A methanolic solution of trans-p-coumaric acid was exposed to ultraviolet radiation and a mixture solution of the trans and cis isomers was subjected to cellulose column chromatography, eluting with an aqueous 0.1% trifluoroacetic acid solution containing methanol (90:10, v/v). Separation of the trans and cis isomers was achieved. The identity of the cis isomer was confirmed by TLC, HPLC, and NMR. Since both the support and eluent are inexpensive, the cis isomers can be obtained economically on both the laboratory and industrial scales.

Blends of amorphous/crystalline nanoalumina and hydrophobic amorphous nanosilica

Initial Al-100 and hydro-compacted amorphous/crystalline nanoalumina cAl-100 alone or in blends with hydrophobic amorphous nanosilica AM1 were characterized using low-temperature 1H NMR and IR spectroscopies, adsorption, XRD, DSC, microscopy, and cryoporometry. Mechanical treatment of weakly hydrated (0.5 g/g) nanooxides results in their hydro-compaction changing many of the material characteristics. There is overlapping of confined space effects for water bound in voids between nanoparticles with effects caused by the colligative properties of aqueous solution of trifluoroacetic acid in a chloroform medium. The interfacial phenomena determine the temperature behavior of bound water/ice depending on dispersion media features. Contact area between unfrozen water and nanooxide surface is smaller than the specific surface area due incomplete water filling of voids between hydrophilic/hydrophobic nanoparticles. In composites with cAl-100/AM1, there is a tendency of diminution of the contact area of water with hydrophobic nanosilica AM1 and hydrophobic chloroform immiscible with water. This effect changes the temperature behavior of water, which becomes more strongly bound to hydrophilic alumina. The observed effects can be of importance upon practical applications of nanooxide based composites.

Electrocatalytic Hydrogen Evolution Reaction Mediated By Co-Hangman-Xanthene-Chlorin Complexes

Chlorins have presented an interesting new class of catalysts for activation of small molecules of energy consequence, more specific, chlorins exhibited higher catalytic activity in hydrogen evolution at low overpotentials versus its porphyrin congeners. A hangman chlorin with a xanthene backbone and a carboxylic acid hanging group positioned above the redox-active macrocycle catalyzes the electrochemical production of hydrogen from trifluoroacetic acid (TFA) and benzoic acid in acetonitrile solutions. The hangman motif provides mechanistic insights into the role of pendant proton relays in governing proton-coupled electron transfer (PCET) involved in the HER. HER by Co chlorins in strong and weak acid reveals Co(II)H is exclusively involved in the generation of H2, but a hydrogen evolution mechanism proceeds by an ECEC mechanism in TFA solution or an EECC mechanism in benzoic acid solution, respectively. Overpotentials for H2 generation are lowered as a result of the hangman effect.

Electrocatalytic properties of manganese and cobalt polyporphine films toward oxygen reduction reaction

Novel member of polymetalloporphines, namely manganese polymetalloporphine of type I (pMnP-I) obtained by ion exchange from magnesium polyporphine of type I (pMgP-I) is reported for the first time and compared to its cobalt analogue (pCoP-I). Both polymer films have been obtained via two-step procedure: demetalation of the pMgP-I electrode film via its exposure to trifluoroacetic acid solution, resulting in formation of the metal-free polyporphine of type I (pH2P-I) followed by electrochemically induced incorporation of Co or Mn ions from the acetonitrile solution of cobalt and manganese perchlorates. A further oxidative transformation of pCoP-I, pMnP-I polymer films has led to the corresponding polyporphines of type II, pCoP-II and pMnP-II, possessing such unique features as condensed polymer structure with a very high density of active sites and high electronic conductivity within a very broad potential range including the one corresponding to the neutral (uncharged) state of the polymer matrix. Both polymers of type II also exhibit interesting electrocatalytic activity toward oxygen electroreduction in aqueous neutral (pH 6.7) and alkaline (pH 13) media which was evaluated under cyclic voltammetric and steady-state conditions. The results demonstrate that the efficiency (regardless of the electrolyte) of both polymetalloporphines is comparable to bare platinum electrode. The effect of annealing of polymer-modified electrodes on their catalytic properties has also been considered.

Composition and Structure of Complexes Formed in Aqueous Solutions of Trifluoroacetic Acid According to IR Spectroscopy Data

The composition and structure of complexes that formed in aqueous solutions of trifluoroacetic acid were studied by frustrated multiple total internal reflection IR spectroscopy (FMTIR). Two types of complexes with a molecular structure formed: trimers CF3COOH · (H2O)2 and cyclic tetramers (CF3COOH)2 · (H2O)2, in which the molecules of the components are arranged in pairs. In the range of acid concentrations from 100% to [H2O]/[CF3COOH] = 1: 1, only these tetramers formed, and all added water was bound into these hydrates. In more dilute solutions (up to [H2O]/[CF3COOH] = 2: 1), CF3COOH · (H2O)2 complexes formed along with tetramers; at a double excess of H2O, the components of the solution were completely bound into these trimers. In dilute solutions (from 0 to 3.6 M CF3COOH), the acid is completely dissociated into H5O 2 + and CF3COO– ions hydrated with water molecules. In the range of medium concentrations (from 3.6 M to [H2O]/[CF3COOH] = 2: 1), the solutions contain both these ions and CF3COOH · (H2O)2 dihydrates. For this range of compositions of the CF3COOH−H2O system, the concentrations of H5O 2 + ions and CF3COOH · (H2O)2 dihydrates were calculated.

Direct detection of carbapenemase-associated proteins of Acinetobacter baumannii using nanodiamonds coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The appearance and spread of carbapenem-resistant Acinetobacter baumannii (CRAB) pose a challenge for optimization of antibiotic therapies and outbreak preventions. The carbapenemase production can be detected through culture-based methods (e.g. Modified Hodge Test-MHT) and DNA based methods (e.g. Polymerase Chain Reaction-PCR). The culture-based methods are time-consuming, whereas those of PCR assays need only a few hours but due to its specificity, can only detect known genetic targets encoding carbapenem-resistance genes. Therefore, new approaches to detect carbapenemase-producing A. baumannii are of great importance. Here, we have developed a rapid and novel method using detonation nanodiamonds (DNDs) as a platform for concentration and extraction of A. baumannii carbapenemase-associated proteins prior to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS) analysis. To concentrate and extract the A. baumannii carbapenemase-associated proteins, we tested several protein precipitation conditions and found a 0.5% trifluoroacetic acid (TFA) solution within the bacterial suspension could result in strong ion signals with DNDs. A total of 66 A. baumannii clinical-isolates including 51 carbapenem-resistant strains and 15 carbapenem-susceptible strains were tested. Our result showed that among the 51 carbapenem-resistant strains 49 strains had a signal at m/z ~40,279 (±87); among the 15 carbapenem-susceptible strains, 4 strains showed a signal at m/z ~40,279. With on-diamond digestion, we confirmed that the captured protein at m/z ~40,279 was related to ADC family extended-spectrum class C beta-lactamase, from A. baumannii. Using this ADC family protein as a biomarker (m/z ~ 40,279) for carbapenem susceptibility testing of A. baumannii, the sensitivity and the specificity could reach 96% and 73% as compared to traditional imipenem susceptibility testing (MIC results). However, the sensitivity and specificity of this method reached 100% as compared to polymerase chain reaction (PCR) result. Our approach could directly detect the carbapenemase-associated proteins of A. baumannii within 90 min and does not require addition of carbapenemase substrate which is required in the MHT or other mass spectrometric methods. For future applications, our method could be efficiently used in the detection of other carbapenemase-producing bacteria.

Fast, quantitative, murine cardiac 19F MRI/MRS of PFCE-labeled progenitor stem cells and macrophages at 9.4T.

PurposeTo a) achieve cardiac 19F-Magnetic Resonance Imaging (MRI) of perfluoro-crown-ether (PFCE) labeled cardiac progenitor stem cells (CPCs) and bone-derived bone marrow macrophages, b) determine label concentration and cellular load limits, and c) achieve spectroscopic and image-based quantification.MethodsTheoretical simulations and experimental comparisons of spoiled-gradient echo (SPGR), rapid acquisition with relaxation enhancement (RARE), and steady state at free precession (SSFP) pulse sequences, and phantom validations, were conducted using 19F MRI/Magnetic Resonance Spectroscopy (MRS) at 9.4 T. Successful cell labeling was confirmed using flow cytometry and confocal microscopy. For CPC and macrophage concentration quantification, in vitro and post-mortem cardiac validations were pursued with the use of the transfection agent FuGENE. Feasibility of fast imaging is demonstrated in murine cardiac acquisitions in vivo, and in post-mortem murine skeletal and cardiac applications.ResultsSPGR/SSFP proved favorable imaging sequences yielding good signal-to-noise ratio values. Confocal microscopy confirmed heterogeneity of cellular label uptake in CPCs. 19F MRI indicated lack of additional benefits upon label concentrations above 7.5–10 mg/ml/million cells. The minimum detectable CPC load was ~500k (~10k/voxel) in two-dimensional (2D) acquisitions (3–5 min) using the butterfly coil. Additionally, absolute 19F based concentration and intensity estimates (trifluoroacetic-acid solutions, macrophages, and labeled CPCs in vitro and post-CPC injections in the post-mortem state) scaled linearly with fluorine concentrations. Fast, quantitative cardiac 19F-MRI was demonstrated with SPGR/SSFP and MRS acquisitions spanning 3–5 min, using a butterfly coil.ConclusionThe developed methodologies achieved in vivo cardiac 19F of exogenously injected labeled CPCs for the first time, accelerating imaging to a total acquisition of a few minutes, providing evidence for their potential for possible translational work.

A rapid high-performance liquid chromatography method for the simultaneous estimation of water-soluble vitamin in ten wild edible plants consumed by the tribal people of North-eastern Region in India

Background: Bauhinia purpurea, Clerodendrum colebrookianum, Dillenia pentagyna, Diplazium esculentum, Houttuynia cordata, Oenanthe linearis, Potentilla lineata, Perilla ocimoides, Sonchus arvensis, and Zanthoxylum acanthopodium are potent wild edible plants and consumed by the tribal people of North-eastern region in India. Objective: A reversed-phase high-performance liquid chromatographic method using photodiode array detector with gradient elution has been developed and validated for the simultaneous quantitation of several water-soluble vitamins such as ascorbic acid (Vitamin C), thiamine (Vitamin B1), riboflavin (Vitamin B2), niacin (Vitamin B3), pantothenic acid (Vitamin B5), pyridoxine (Vitamin B6), and folic acid (Vitamin B9) in these ten wild edible plants. Materials and Methods: The chromatographic separation of vitamins was carried out on Acclaim C 18 column (5 μm particle size, 250 mm × 4.6 mm), Dionex Ultimate 3000 liquid chromatograph and detection was carried out at three different wave lengths (210, 245, and 254 nm) using a mobile phase of acetonitrile and aqueous trifluoroacetic acid (0.01% v/v) solution with gradient elution. Conclusion: The results of investigation showed that these plants are rich sources of vitamins, especially the B group of vitamins that can contribute immensely to nutrition, food security, and health and therapeutic benefits. The high percentage of recovery (98%–99%), low coefficient of variation (R2 > 0.99), low limit of detection, and limit of quantitation confirm the suitability of the method for simultaneous quantification of vitamins in these ten plants under investigation. Abbreviations used: RSD: Relative standard deviation; LOD: Limit of detection; LOQ: limit of quantification; SEM: Standard error of mean; ND: Not detected; DPM: Dried plant material; TFA: Trifluoroacetic acid; v/v: Volume by volume; HPLC: High-performance liquid chromatography; nm: Nanometer; mg: Milligram; μg: Microgram; R2: Regression coefficient.

Reduction of Graphene Oxide Thin Films by Cobaltocene and Decamethylcobaltocene.

Reduced graphene oxide (RGO) films have been prepared by immersion of graphene oxide (GO) films at room temperature in nonaqueous solutions containing simple, outer-sphere metallocene reductants. Specifically, solutions of cobaltocene, cobaltocene and trifluoroacetic acid (TFA), and decamethylcobaltocene each showed activity for the rapid reduction of GO films cast on a wide variety of substrates. Each reactant increased the conductivity of the films by several orders of magnitude, with RGO films prepared with either decamethylcobaltocene or cobaltocene and TFA possessing the highest conductivities (∼104 S m-1). X-ray photoelectron spectroscopy suggested that while all three reagents lowered the content of carbon-oxygen functionalities, solutions of cobaltocene and TFA were the most effective at reducing the material to sp2 carbon. Separately, Raman spectra and atomic force micrographs indicated that RGO films prepared with decamethylcobaltocene consisted of the largest graphitic domains and lowest macroscopic roughness. Cumulatively, the data suggest that the outer-sphere reductants can affect the conversion to RGO but the reactivity and mechanism depend on the standard potential of the reductant and the availability of protons. This work both demonstrates a new way to prepare high-quality RGO films on a wide range of substrate materials without annealing and motivates future work to elucidate the chemistry of RGO synthesis through the tunability of outer-sphere reductants such as metallocenes.

DEVELOPMENT OF ULTRA-HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE DETERMINATION OF CAPTOPRIL IN PHARMACEUTICAL DOSAGE FORMS

Objective: The objective of this research was to develop more simple, sensitive, accurate, and less expensive analytical methods for the determination of captopril in medicines by Ultra-high-performance liquid chromatography.Materials and Methods: The chromatographic analysis of captopril performed on liquid chromatography Agilent 1290 Infinity II LC System.Results: A simple, rapid, sensitive, and specific method was developed for the determination of captopril by ultra-high-performance liquid chromatography in mono-medicines and pharmaceutical dosage forms in combination with hydrochlorothiazide without previous separation. Satisfactory resolution was achieved using Fused-Core® technology Ascentis Express C18 column (4.6×150 mm) and a mobile phase consisting of methanol and 0.1% solution of trifluoroacetic acid (40/60, v/v) at a flow rate 1.2 mL/minute and the wavelength detection was 220 nm. Ascentis Express columns, based on Fusеd-core pаrticle technоlogy, prоvide more than twice the speed and efficiency of traditiоnal cоlumns at half the backpressure of sub-2-μm columns. The retention time for captopril was 1.345 minute. The validation of this method was based on the ICH and USP guidelines.Conclusion: The results obtained in this research work clearly indicated that the assay was rapid, sensitive and successfully applied to the determination of both drugs in pharmaceutical dosage forms without interference from tablet excipients.

Synthesis of nanostructural Yttrium fluorosilicate glass ceramic via sol–gel method

The yttrium fluorosilicate glass ceramic pieces were prepared by sol–gel method starting from yttrium acetate, trifluoroacetic acid, and tetraethylorthosilicate solutions. The starting solution composition and heating pattern were considered as variables for finding the optimum condition. Evaluated activation energy of crystallization by classical Kissinger method was 174.462 kJ/mol. The estimated Avrami exponents from Ozawa and Augis-Bennett equations were 1.167 and 1.357, respectively. They both indicate domination of surface crystallization. In addition, obvious YF3 crystallization peaks in sample heated from ambient temperature (20 °C) to 320 °C and then 60 °C and keeping at each mentioned temperature for 2 h resulted in higher surface area (more cracks) thereby confirming the surface crystallization, while heating from ambient temperature to 600 °C and keeping samples for 5 h at every 50 °C temperature increments above 200 °C resulted in weaker peaks in XRD pattern. XRD pattern of YF3 precursor showed that crystallization occurred at 300 °C, according to DTA result. Crystallization temperature of glass ceramic varies from 315.64 to 337.20 °C depending on its heating rate. SEM micrographs showed that extending the heat treatment process causes the distribution of YF3 crystals in the matrix and prevent them from forming congeries. To obtain transparent and crack free sample, N2 atmosphere was utilized to separate decarburization and combustion stages. Fig. I. XRD patterns and pictures of samples heat treated from ambient temperature to a 320 °C and then 600 °C and keeping at each mentioned temperature for 2 h, b 320 °C and then 600 °C and keeping at each mentioned temperature for 10 h, and c 600 °C and keeping sample at every 50 °C temperature increments above 200 °C for 5 h.

Immobilized Cobalt Bis(benzenedithiolate) Complexes: Exceptionally Active Heterogeneous Electrocatalysts for Dihydrogen Production from Mildly Acidic Aqueous Solutions.

A series of cobalt bis(benzenedithiolate) complexes with varying benzenedithiolate (general abbreviation: bdt2-) ring substitutions (S2C6X42-) were prepared and adsorbed on inexpensive electrodes composed of (a) reduced graphene oxide (RGO) electrodeposited on fluorine-doped tin oxide (FTO) and (b) highly ordered pyrolytic graphite (HOPG). The catalyst-adsorbed electrodes are characterized by X-ray photoelectron spectroscopy. Catalyst loading across the ligand series improved notably with increasing halide substitution [from 2.7 × 10-11 mol cm-2 for TBA[Co(S2C6H4)2] (1) to 6.22 × 10-10 mol cm-2 for TBA[Co(S2C6Cl4)2] (3)] and increasing ring size of the benzenedithiolate ligand [up to 3.10 × 10-9 mol cm-2 for TBA[Co(S2C10H6)2] (6)]. Electrocatalytic analysis of the complexes immobilized on HOPG elicits a reductive current response indicative of dihydrogen generation in the presence of mildly acidic aqueous solutions (pH 2-4) of trifluoroacetic acid, with overpotentials of around 0.5 V versus SHE (measured vs platinum). Rate constant (kobs) estimates resulting from cyclic voltammetry analysis range from 24 to 230 s-1 with the maximum kobs for TBA[Co(S2C6H2Cl2)2] (2) at an overpotential of 0.59 V versus platinum. Controlled-potential electrolysis studies performed in 0.5 M H2SO4 at -0.5 V versus SHE show impressive initial rate constants of over 500 s-1 under bulk electrolysis conditions; however, steady catalyst deactivation over an 8 h period is observed, with turnover numbers reaching 9.1 × 106. Electrolysis studies reveal that halide substitution is a central factor in improving the turnover stability, whereas the ring size is less of a factor in optimizing the long-term stability of the heterogeneous catalyst manifolds. Catalyst deactivation is likely caused by catalyst desorption from the electrode surfaces.

General trends in concentration and temperature behavior of equivalent conductance of N,N-diallylammonium polymers aqueous solutions: Effect of counterion nature and amine structure

The specific and equivalent conductivity of the diluted aqueous solutions of diallyammonium polyelectrolytes, initial monomers (N,N-diallylammonium trifluoroacetate, N,N-diallyl-N-methylammonium trifluoroacetate, N,N-diallyl-N,N-dimethylammonium chloride), and also potassium trifluoroacetate and trifluoroacetic acid solutions are studied. The limiting ionic mobility of diallylammonium cations and trifluoroacetate anion are found. The regularities of concentration changes in the equivalent conductance of polyelectolytes solutions are established. The degree of dissociation of diallyammonium polymers is shown to depend both on the counterion nature and on the amine structure.

A new type of the dinitrogen pentoxide–acid interaction

Dinitrogen pentoxide solution in trifluoroacetic acid simultaneously has features of both known types of its interaction with acids, viz . with weak and strong acids. It partially reacts with CF 3 COOH to give the covalent trifluoroacetyl nitrate and nitric acid, however the major part of N 2 O 5 exists in the covalent form in solution to concurrently produce nitronium ions due to the presence of HNO 3 . Quantum chemical calculations confirm the equilibrium nature of CF 3 COOHN 2 O 5 interaction.

Fabrication and morphology of uniaxially aligned perylenediimide nanowires

Uniaxial alignment of crystalline nanowires consisting of N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) was achieved on poly(tetrafluoroethylene) (PTFE) layers prepared by friction transfer method on a glass substrate. The nanowires were formed by spin-coating a trifluoroacetic acid (TFA) solution of PTCDI-C8 on the PTFE layers and were further grown under TFA vapor atmosphere. The morphology of the PTCDI-C8 nanowires were characterized using atomic force microscope (AFM) and fluorescence optical microscope with changing the dye concentration in the spin coating solution, annealing time in the TFA vapor, and substrate materials. The nanowires prepared on the PTFE layer on a silica-coated silicon or a mica substrate did not grow so well as those on the glass substrate. This result suggests that the surface roughness would affect the PTFE layer and the growth of the PTCDI nanowires.

Intermolecular interactions between B. mori silk fibroin and poly(l-lactic acid) in electrospun composite nanofibrous scaffolds

In this study, composite nanofibrous scaffolds were obtained by electrospinning a trifluoroacetic acid solution containing B. mori silk fibroin (SF) and poly(l-lactic acid) (PLLA) in a 1:1 weight ratio. SF, PLLA and SF/PLLA nanofibres were prepared with average diameter sizes of 360±90nm, 470±240nm and 580±220nm, respectively, as assessed by SEM analysis.Vibrational and thermal analyses showed that upon blending in the SF/PLLA nanofibres, the crystallisation of PLLA was hindered by the presence of SF, which crystallized preferentially and underwent conformational changes that did not significantly change its prevailing β-sheet structure. The two components were thermodynamically compatible and the intermolecular interactions between them were revealed for the first time.Human keratinocytes were cultured on nanofibres and their viability and proliferation were determined. Preliminary in vitro tests showed that the incorporation of SF into the PLLA component enhanced cell adhesion and proliferation with respect to the unfunctionalised material. SF has been successfully used to modify the biomaterial properties and confirmed to be an efficient bioactive protein to mediate cell-biomaterial interaction.

Preparation of cobalt polyporphine and its catalytic properties in oxygen electroreduction

A new member of the polyporphine series—cobalt polyporphine of type I (pCoP-I)—was prepared from the starting magnesium polyporphine of type I (pMgP-I) by ion exchange, i.e. by sequential processing of the pMgP-I polymer film on the electrode surface with solutions of trifluoroacetic acid (forming metalfree polyporphine of type I, pH2P-I) and cobalt(II) acetate in organic solvents. The completeness of each stage of ion exchange can be judged from the change in the electrochemical and spectral characteristics of the obtained polymer films of unsubstituted porphine (?H2P-I) and cobalt porphine (pCoP-I) of type I. Oxidative transformation of this polyporphine pCoP-I was performed, which led to the formation of additional bonds between the neighboring porphine units in the polymer film (transition of polymer of type I into polymer of type II, pCoP-II). The behavior of the polymer films of cobalt polyporphine of types I and II in oxygen electroreduction was studied. The films showed catalytic activity in this process.

Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

In this work, thin films of chloroaluminium phthalocyanine (ClAlPc), fluoroaluminium phthalocyanine (FAlPc) and fluorochromium phthalocyanine (FCrPc), which are insoluble in conventional solvents, were deposited by spin coating of their solutions in trifluoroacetic acid. The sensing response of these films versus acetic acid, three alcohols (methanol, ethanol, butanol) and three amines (methylamine, dimethylamine, trimethylamine) have been investigated using surface plasmon resonance as the sensing method. It has been shown that the sensor response of the investigated films decreases in the following order: acetic acid>alcohols>amines. The optical changes as monitored by SPR method have been used in conjunction with Fick's second law of diffusion to determine the diffusion coefficients of analyte vapor during the films’ swelling process. The obtained results showed that the diffusion coefficients and the swelling characteristics of the films are dependent on the functional group of the phthalocyanine molecule and the molecular size of the analyte.

A single laboratory-validated LC-MS method for the analysis of tulathromycin residues in bison and deer sera and selected tissues of white-tailed deer.

The performance characteristics of a newly developed liquid chromatography-mass spectrometry (LC-MS) method were validated and demonstrated to be fit for purpose in a pharmacokinetic and tissue depletion study of white-tailed deer and bison. Tulathromycin was extracted from bison and deer sera with acetonitrile or trifluoroacetic acid and K2 HPO4 (pH 6.8) buffer solution and cleaned up on a conditioned Bond-Elut cartridge. Tulathromycin, retained on the cartridge; it was eluted with methanol containing 2% formic acid, dried, re-constituted in methanol/1% formic acid, and analyzed by LC-MS. The limit of quantification (LOQ) of the method was 0.6 ng/mL in serum and 0.6 ng/g in tissue with RSDs ≤ 10% and accurate over the linear calibration range of 0.8-100 ng/mL for bison serum, 0.6-50 ng/mL for deer serum, 100-2500 ng/g for deer muscle tissue, and 500-5000 ng/g for deer lung tissue, all with coefficients of determination, r(2) ≥0.99. The validated method was used to quantify the concentration of tulathromycin residues in serum of bison and deer and selected tissue (lung and muscle tissue) samples obtained from 10 healthy, white-tailed deer that were administered the therapeutic dose approved for cattle (i.e., a single 2.5 mg/kg subcutaneous injection of tulathromycin in the neck). The deer were included in a tulathromycin drug depletion study. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis © 2016 John Wiley & Sons, Ltd.