Ian S. Campbell, Alain T. Ton, and Christopher, C. Mulligan*

Supporting Information For:

Direct Detection of Pharmaceuticals and Personal Care Products from Aqueous Samples with Thermally Assisted Desorption Electrospray Ionization Mass Spectrometry

Ian S. Campbell, Alain T. Ton, and Christopher, C. Mulligan*

Department of Chemistry, Illinois State University, Normal, IL 61790

*Corresponding author: Email:

Table of ContentsPage

Table S-1. Analytes investigated with Method 1 (Direct Flow Injection DESI-MS)

Figure S-1. (a) Positive ion DESI mass spectrum of an aqueous solution containing ~ 2.5 ppm diphenhydramine, showing the protonated molecule at m/z 256. (b) MS2 of the m/z 256 precursor gives the major transition at m/z 167, corresponding to the loss of N,N-dimethyl-2-aminoethanol.

Diphenhydramine Analysis

Figure S-1a shows a positive ion DESI mass spectrum of an aqueous solution containing ~2.5 ppm pseudoephedrine using Method 1. Diphenhydramine is a common antihistamine and is the active ingredient in the over the counter (OTC) pharmaceutical tablet Benadryl®. The protonated molecule [M+H]+ is seen at m/z 256, as well as other ions corresponding to the sample matrix and common electrospray background. Isolation and fragmentation of m/z 256 leads to a loss of N,N-dimethyl-2-aminoethanol, seen as the ion at m/z 167 (Figure S-1b), similar to fragmentation reported in literature.1

Figure S-2. (a) Positive ion DESI mass spectrum of an aqueous solution containing ~ 100 ppb loratadine, showing the protonated molecule as a chlorine doublet at m/z 383 and 385. (b) MS2 of the m/z 383 precursor gives the major transition at m/z 337, corresponding to the loss of ethanol.

Loratadine Analysis

Figure S-2a shows a positive ion DESI mass spectrum of an aqueous solution containing ~ 100 ppb loratadine using Method 1. Loratadine is a common antihistamine and is the active ingredient in the OTC pharmaceutical tablet Claritin®. The protonated molecule [M+H]+ is seen at m/z 383 and 385 as a chlorine doublet, as well as other ions corresponding to the sample matrix and common electrospray background. Isolation and fragmentation of m/z 383 leads to a loss of ethanol, seen as the ion at m/z 337 (Figure S-2b), similar to fragmentation reported in literature.2

Figure S-3. (a) Positive ion DESI mass spectrum of an aqueous solution containing ~ 3 ppm pseudoephedrine, showing the protonated molecule at m/z 166. (b) MS2 of the m/z 166 precursor gives the major transition at m/z 148, corresponding to the loss of water.

Pseudoephedrine Analysis

Figure S-3a shows a positive ion DESI mass spectrum of an aqueous solution containing ~3 ppm pseudoephedrine using Method 1. Pseudoephedrine is a common decongestant and stimulant, and it is the active ingredient in the OTC pharmaceutical tablet Sudafed® Congestion. The protonated molecule [M+H]+ is seen at m/z 166, as well as other ions corresponding to the sample matrix and common electrospray background. Isolation and fragmentation of m/z 166 leads to a loss of water, seen as the ion at m/z 148 (Figure S-3b), similar to fragmentation reported in literature.3

Figure S-4. (a) Positive ion DESI mass spectrum of an aqueous solution containing ~100 ppb each of phenylephrine and chlorpheniramine, showing the protonated molecules at m/z 168 and m/z 275/277, respectively. (b) MS2 of the m/z 168 precursor of phenylephrine gives the major transition at m/z 150, corresponding to the loss of water. (c) MS2 of the m/z 275 precursor of chloropheniramine gives the major transition at m/z 230, corresponding to the loss of dimethylamine.

Phenylephrine and Chloropheniramine Analysis

Figure S-4a shows a positive ion DESI mass spectrum of an aqueous solution containing ~100 ppb each of phenylephrine and chloropheniramine, showing the protonated molecules at m/z 168 and m/z 275/277, respectively, using Method 1. Phenylephrine is a common decongestant and chlorpheniramine is a common antihistamine, and they are the active ingredients in OTC pharmaceutical tablet Sudafed PE® Sinus and Allergy. Isolation and fragmentation of the m/z 168 precursor of phenylephrine gives the major transition at m/z 150, corresponding to the loss of water (Figure S-4b). Isolation and fragmentation of the m/z 275 precursor of chloropheniramine gives the major transition at m/z 230, corresponding to the loss of dimethylamine (Figure S-4c).4

Table S-2. Analytes investigated with Method 2 (Thermally-Assisted DESI-MS)

Figure S-5. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb amitriptyline, showing the protonated molecule at m/z 278. (b) MS2 of the m/z 278 precursor gives the major transition at m/z 233, corresponding to the loss of dimethylamine.

Amitriptyline Analysis

Figure S-5a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb amitriptyline using Method 2, showing the protonated molecule at m/z 278. Amitriptyline is a tricyclic antidepressant (TCA), and is the active ingredient in Elavil®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 278 precursor leads to a loss of dimethylamine seen as the ion at m/z 233 (Figure S-5b), similar to fragmentation reported in literature.5

Figure S-6. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb atenolol, showing the protonated molecule at m/z 267. (b) MS2 of the m/z 267 precursor gives rise to the major transition at m/z 190, corresponding to an ion of composition [M-H2O - NH3 -isopropyl + 2H]+.

Atenolol Analysis

Figure S-6a shows a positive ion DESI mass spectrum of a tap water solution containing 100 ppb atenolol using Method 2, showing the protonated molecule and sodium adduct at m/z 267 and 289, as well as the dimer and sodiated dimer at m/z 532 and 554. Atenolol belongs to pharmaceutical class of β-blockers (β1 receptor antagonist) and is used extensively in the treatment of hypertension. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 267 precursor leads to a diverse fragmentation pattern (Figure S-6b), with the highest intensity transition corresponding to [M -H2O - NH3 - isopropyl + 2H]+, similar to fragmentation reported in literature.6

Figure S-7. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb bupropion, showing the protonated molecule as a chlorine doublet at m/z 240 and 242. (b) MS2 of the m/z 240 precursor gives the major transition at m/z 184, corresponding to the loss of isobutene.

Bupropion Analysis

Figure S-7a is a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb bupropion, showing the protonated molecule as a chlorine doublet at m/z 240 and 242. Bupropion is an aminoketone antidepressant, and is the active ingredient in Wellbutrin®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 240 precursor leads to a loss of isobutene seen as the ion at m/z 184 (Figure S-7b), similar to fragmentation reported in literature.7

Figure S-8. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb chlorpheniramine, showing the protonated molecule as a chlorine doublet at m/z 275 and 277. (b) (b) MS2 of the m/z 275 precursor ion of chlorpheniramine, yielding a product ion at m/z 230, corresponding to a loss of ethylamine.

Chlorpheniramine Analysis

Representative spectra obtained for analysis of 100 ppb aqueous solutions of chlorpheniramine can be seen Figure S-8a. Chlorpheniramine, a histamine receptor antagonist, is commonly incorporated individually or in conjunction with decongestants in pharmaceutical compositions. Positive ion DESI analysis utilizing Method 2 yielded the protonated molecule for chlorpheniramine with a chlorine isotopic distribution at m/z 275 and 277. Figure S-8b shows the MS2 spectrum of the m/z 275 precursor ion (corresponding to the 35Cl isotope), which dissociates by loss of ethylamine to produce an ion of m/z 230.

Figure S-9. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb citalopram, showing the protonated molecule at m/z 325. (b) Fragmentation of the m/z 325 precursor of citalopram yields several product ions, with the main product at m/z 262 corresponding to a loss of 2-fluoro-ethylamine.

Citalopram Analysis

Figure S-9a shows a positive ion DESI mass spectrum using Method 2 for 100 ppb citalopram in tap water. Citalopram is in the selective serotonin reuptake inhibitor (SSRI) class of antidepressants, and is marketed as the product Celexa®. Citalopram is seen as the protonated molecule at m/z 325. Fragmentation of the m/z 325 precursor yields several product ions, as seen in Figure S-9b, with the main product at m/z 262 corresponding to a loss of 2-fluoro-ethylamine.

Figure S-10. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb clomipramine, showing the protonated molecule as a chlorine doublet at m/z 315 and 317. (b) MS2 of the m/z 315 precursor gives the major transition at m/z 270, corresponding to the loss of dimethylamine.

Clomipramine Analysis

Figure S-10a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb clomipramine, yielding the protonated molecule as a chlorine doublet at m/z 315 and 317. Clomipramine is a TCA antidepressant, and is the active ingredient in Anafril®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 315 precursor leads to a loss of dimethylamine, seen as the ion at m/z 270 (Figure S-10b).

Figure S-11. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb duloxetine, showing the protonated molecule at m/z 298. (b) MS2 of the m/z 298 precursor gives the major transition at m/z 267, corresponding to the loss of methylamine.

Duloxetine Analysis

Figure S-11a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb duloxetine, yielding the protonated molecule at m/z 298. Duloxetine is a serotonin-norepinephrine reuptake inhibitor antidepressant, and is the active ingredient in Cymbalta®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 298 precursor leads to the presence of product ions at m/z 154 and 267, corresponding to a loss of 1-naphthol and methylamine, respectively, similar to fragmentation reported in literature.7

Figure S-12. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb estradiol, showing the protonated molecule at m/z 273. Of note, in-source fragmentation is seen in high intensity, resulting in the loss of water (m/z 255) from the precursor ion. (b) MS2 of the m/z 273 precursor gives the major transition at m/z 255, corresponding to the loss of water.

Estradiol Analysis

Figure S-12a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb estradiol, yielding the protonated molecule at m/z 273. Estradiol, or 17β-estradiol, is the predominant female sex hormone, but is also used extensively in mediations that treat hypoestrogenism. As a result of the thermal assistance, a high intensity ion is seen at m/z 255, corresponding to a thermal fragmentation that results in a loss of water. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 273 precursor leads to the major transition seen at m/z 255, corresponding to a loss of water, as seen in Figure S-12b.

Figure S-13. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb fluoxetine, showing the protonated molecule at m/z 310. (b) MS2 of the m/z 310 precursor gives the major transition at m/z 148, corresponding to the loss of p-hydroxybenzotrifluoride.

Fluoxetine Analysis

Figure S-13a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb fluoxetine, yielding the protonated molecule at m/z 310. Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant, and is the active ingredient in the commonly-used tablet Prozac®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 310 precursor leads to a loss of p-hydroxybenzotrifluoride seen as the ion at m/z 148 (Figure S-13b), similar to fragmentation reported in literature.7

Figure S-14. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb imipramine, showing the protonated molecule at m/z 281. (b) MS2 of the m/z 281 precursor gives the major transition at m/z 86, corresponding to the loss of 2,2'-iminodibenzyl.

Imipramine Analysis

Figure S-14a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb imipramine, yielding the protonated molecule at m/z 281. Imipramine is a TCA antidepressant, and is the active ingredient in Antideprin®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 281 precursor leads to a loss of 2,2'-iminodibenzyl, seen as the ion at m/z 86 (Figure S-14b).

Figure S-15. (a) Positive ion DESI mass spectrum of an aqueous solution containing 1 ppm moxifloxacin, showing the protonated molecule at m/z 402, as well as sodiated and potassiated adducts at m/z 424 and 440, respectively.. (b) MS2 of the m/z 402 precursor gives the major transition at m/z 384, corresponding to the loss of water.

Moxifloxacin Analysis

Figure S-15a shows a positive ion DESI mass spectrum of a tap water solution containing 1 ppm moxifloxacin, yielding the protonated molecule at m/z 402 and adducts with sodium and potassium at m/z 424 and 440, respectively. Moxifloxacin is a fluoroquinolone antibacterial and broad spectrum antibiotic, and it is used in both oral (bacterial infections) and ophthalmic solutions (conjunctivitis). Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 402 precursor leads to a loss of water, seen as the ion at m/z 86 (Figure S-15b).

Figure S-16. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb nortriptyline, showing the protonated molecule at m/z 264. (b) MS2 of the m/z 264 precursor gives the major transition at m/z 233, corresponding to the loss of methylamine.

Nortriptyline Analysis

Figure S-16a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb nortriptyline, yielding the protonated molecule at m/z 264. Nortriptyline is a TCA antidepressant, and is the active ingredient in Antideprin®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 281 precursor leads to a loss of methylamine, seen as the ion at m/z 233 (Figure S-16b).6

Figure S-17. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb paroxetine, showing the protonated molecule at m/z 330. (b) MS2 of the m/z 330 precursor gives the major transition at m/z 192, corresponding to the loss of 1,3-benzodioxol-5-ol.

Paroxetine Analysis

Figure S-17a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb paroxetine, yielding the protonated molecule at m/z 330. Paroxetine is a SSRI antidepressant, and is the active ingredient in Paxil®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 330 precursor leads to a loss of 1,3-benzodioxol-5-ol, seen as the ion at m/z 192 (Figure S-17b).8

Figure S-18. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb sertraline, showing the protonated molecule at m/z 306, 308, and 310, corresponding to the characteristic dichlorinated isotopic signature. (b) MS2 of the m/z 308 precursor gives the major transition at m/z 275, corresponding to the loss of methylamine.

Sertraline Analysis

Figure S-18a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb sertraline, yielding the protonated molecule at m/z 306, 308, and 310, corresponding to the characteristic dichlorinated isotopic signature. Sertraline is in the selective serotonin reuptake inhibitor (SSRI) class of antidepressants, and is marketed as the product Zoloft®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 306 precursor leads to a loss of methylamine, seen as the ion at m/z 275 (Figure S-18b).6

Figure S-19. (a) Positive ion DESI mass spectrum of an aqueous solution containing 100 ppb venlafaxine, showing the protonated molecule at m/z 278. (b) MS2 of the m/z 278 precursor gives the major transition at m/z 260, corresponding to the loss of water.

Venlafaxine Analysis

Figure S-19a shows a positive ion DESI mass spectrum of an aqueous solution containing 100 ppb venlafaxine, yielding the protonated molecule at m/z 278. Venlafaxine is a serotonin-norepinephrine reuptake inhibitor antidepressant, and is the active ingredient in Effexor®. Other spectral peaks correspond to the heated surface and common ESI background. Isolation and fragmentation of the m/z 278 precursor leads to a loss of water, seen as the ion at m/z 260 (Figure S-19b).8

References

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(2) Cotte-Rodríguez, I.; Mulligan, C. C.; Cooks, R. G. Non-Proximate Detection of Small and Large Molecules by Desorption Electrospray Ionization and Desoprtion Atmospheric Pressure Chemical Ionization Mass Spectrometry: Instrumentation and Applications in Forensics, Chemistry, and Biology. Anal. Chem. 2007, 79, 7069-7077.

(3) Zou, H.; Gao, S.; Chen, W.; Zhong, Y.; Jiang, X.; Pei, Y. Simultaneous Quantitation of Paracetamol, Pseudoephedrine and Chlorpheniramine in Dog Plasma by LC-MS-MS. Chromatographia 2008, 68, 251-257.

(4) Marín, A.; Espada, A.; Vidal, P.; Barbas, C. Major Degradation Products Identified in Several Pharmaceutical Formulations Against the Common Cold. Anal. Chem. 2005, 77, 471-477.

(5) Kirchherr, H.; Kühn-Velten, W. N. Quantitative Determination of Forty-Eight Antidepressants and Antipsychotics in Human Serum by HPLC Tandem Mass Spectrometry: A Multi-Level, Single-Sample Approach. J. Chromatogr., B: Anal. Technol. Biomed. Life Sci. 2006, 843, 100-113.

(6) Hernando, M. D.; Petrovic, M.; Fernández-Alba, A. R.; Barceló. Analysis by Liquid Chromatography-Electrospray Ionization Mass Spectrometry and Acute Toxicity Evaluation for β-Blockers and Lipid-Regulating Agents in Wastewater Samples. J. Chromatogr., A. 2004, 1046, 133-140.

(7) Schultz, M. M.; Furlong, E. T. Trace Analysis of Antidepressant Pharmaceuticals and Their Select Degradates in Aquatic Matrices by LC/ESI/MS/MS. Anal. Chem. 2008, 80, 1756-1762.

(8) Lajeunesse, A.; Gagnon, C.; Sauvé, S. Determination of Basic Antidepressants and Their N-Desmethyl Metabolites in Raw Sewage and Wastewater Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry. Anal. Chem. 2008, 80, 5325-5333.

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