Fast analysis of high‐energy compounds and agricultural chemicals in water with desorption electrospray ionization mass spectrometry

Abstract. Desorption atmospheric pressure chemical ionization (DAPCI) is implemented on a portable mass spectrometer and applied to the direct detection of polycyclic aromatic hydrocarbons (PAHs) and alkyl substituted benzenes. The presence of these compounds in the environment poses a significant threat to the health of both humans and wildlife because of their carcinogenic, toxic, and mutagenic properties. As such, instant detection outside of the laboratory is of particular importance to allow in-situ measurement at the source. Using a rapid, high throughput, miniature, handheld mass spectrometer, several alkyl substituted benzenes and PAHs (i.e., 1,2,3,5-tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, fluoranthene, anthracene, benzo[k]fluoranthene, dibenz [a,h]anthracene, acenaphthene, indeno [1,2,3-c,d]pyrene, 9-ethylfluorene, and 1-benzyl-3-methyl-naphthalene) were identified and characterized using tandem mass spectrometry (MS/MS) from ambient surfaces, in the open air. This method can provide almost instantaneous information while minimizing sample preparation, which is advantageous in terms of both cost and simplicity of analysis. This MS-based technique is applicable to a wide range of environmental organic molecules.

Section: Introductionmentioning

confidence: 99%

Analysis of Polycyclic Aromatic Hydrocarbons Using Desorption Atmospheric Pressure Chemical Ionization Coupled to a Portable Mass Spectrometer

Jjunju

Maher

et al. 2014

“…Recently, two novel sample introduction methods have been reported for the analysis of solution samples either using DESI or DeSSI. One is to add aqueous samples onto a cotton swab or filter paper followed by DESI analysis [31,32]. The other is to use a permeable membrane to enrich analytes from solutions, which can be desorbed and ionized from the other side of the membrane after penetrating the membrane [33].…”

mentioning

confidence: 99%

Direct analysis of liquid samples by desorption electrospray ionization-mass spectrometry (DESI-MS)

Miao

Chen

2009

150

192

Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the direct analysis of liquid samples. Several interesting results were found. First, in contrast to the previous DESI analysis of dried solid samples that was limited to proteins with MW Յ 25 kDa (Anal. Chem. 2007, 79, 3514), bovine serum albumin (BSA, 66 kDa) was successfully ionized from solutions by DESI with observation of corresponding multiply charged ions. Second, direct DESI analysis of protein tryptic digest solutions without chromatographic separation, sample clean-up, and the sample drying step was demonstrated, providing reasonably good sequence coverage of 52% to 97%. Third, direct analysis of biofluids such as an undiluted urine sample without sample pretreatment is possible, emphasizing the high tolerance of DESI with salt. These results suggest that a charged droplet pick-up mechanism is responsible for desorption and ionization of liquid samples by DESI. Also, unlike in electrospray ionization (ESI), inhibition of electrochemical reduction in the negative ion mode was observed for liquid sample DESI. In addition, reactive DESI can be performed with ion/ion reactions of Zn(II) complexes for the selective binding of phosphoserine in the presence of serine. DESI experiment can also be carried out directly to liquid samples flowing out of a pumped syringe needle tip, allowing rapid analysis. Furthermore, on-line coupling of electrochemical cell with DESI-MS was demonstrated, in which perylene radical cations generated in the cell were successfully transferred to the gas-phase for MS detection by DESI. This study extended the scope of DESI-MS applications, which could have potentials in bioanalytical and forensic analysis. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] have been introduced as rapid tools to provide efficient desorption, ionization, and further mass spectrometric characterization of target compounds. As a representative ambient ionization method, desorption electrospray ionization (DESI) has become very successful in the fast analysis of a variety of different analytes including pharmaceuticals [17][18][19], metabolites [20,21], drugs of abuse [22,23], explosives [24 -26], chemical warfare agents [27], and even intact tissues [28,29] as well as thin-layer chromatography plate [30]. In the DESI experiments, ionization occurs via the interaction of charged microdroplets generated in a pneumatically assisted electrospray of an appropriate solvent with samples placed on surfaces. Typically, solid samples on the surface are desorbed and ionized during DESI-MS analysis, and liquid samples typically undergo drying on surface in air before ionization. One practical reason for this is that liquid samples could be blown away from the surface immediately (i.e., splashing of liquids) by the high-velocity nebulizing gas employed for the generation of charged microdroplets. As a consequence, the resulting ion signal, if any, will not last long. Recently, two novel sample introduction methods have been reported ...

“…In DESI-MS, samples are analyzed by directing a pneumatically-assisted stream of charged microdroplets at the surface in the ambient environment. The potential utility of DESI in highthroughput analysis is obvious since samples do not need prior preparation or transfer into vacuum, and there are numerous reports in the literature demonstrating rapid sample analysis by DESI [12][13][14][15]. Reports of high-throughput analysis in which a large number of samples are analyzed quickly in rapid succession are much fewer [16].…”

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confidence: 99%

High-throughput quantitative analysis by desorption electrospray ionization mass spectrometry

Manicke

Kistler

Ifa

et al. 2009

Self Cite

A newly developed high-throughput desorption electrospray ionization (DESI) source was characterized in terms of its performance in quantitative analysis. A 96-sample array, containing pharmaceuticals in various matrices, was analyzed in a single run with a total analysis time of 3 min. These solution-phase samples were examined from a hydrophobic PTFE ink printed on glass. The quantitative accuracy, precision, and limit of detection (LOD) were characterized. Chemical background-free samples of propranolol (PRN) with PRN-d 7 as internal standard (IS) and carbamazepine (CBZ) with CBZ-d 10 as IS were examined. So were two other sample sets consisting of PRN/PRN-d 7 at varying concentration in a biological milieu of 10% urine or porcine brain total lipid extract, total lipid concentration 250 ng/ L. The background-free samples, examined in a total analysis time of 1.5 s/sample, showed good quantitative accuracy and precision, with a relative error (RE) and relative standard deviation (RSD) generally less than 3% and 5%, respectively. The samples in urine and the lipid extract required a longer analysis time (2.5 s/sample) and showed RSD values of around 10% for the samples in urine and 4% for the lipid extract samples and RE values of less than 3% for both sets. The LOD for PRN and CBZ when analyzed without chemical background was 10 and 30 fmol, respectively. The LOD of PRN increased to 400 fmol analyzed in 10% urine, and 200 fmol when analyzed in the brain lipid extract. (J Am Soc Mass Spectrom 2009, 20, 321-325) © 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry Q uantitative analysis of pharmaceutical compounds in biological fluids is typically carried out using liquid chromatography separation combined with a mass spectrometer fitted with an atmospheric pressure ionization (API) ion source, usually electrospray ionization or atmospheric pressure chemical ionization (LC/ESI-MS or LC/APCI-MS). Such a system can analyze one sample for numerous components in a matter of a few minutes [1]. In most applications, the separation device is directly coupled on-line with the MS. In others, however, extensive prior separation is not necessary, and it can be replaced by a simpler extraction step. In these cases, current highthroughput approaches include direct injection of the sample solution into the MS from a 96-well sample plate for analysis by API [2], or the spotting of solid samples with an organic matrix for analysis by matrix-assisted laser desorption/ionization (MALDI) [3].New options for the ionization of samples at atmospheric pressure have emerged recently. The family of ambient ionization methods for mass spectrometry, which originated with desorption electrospray ionization (DESI) [4] and direct analysis in real time (DART) [5], has rapidly expanded to include a number of new members including MALDESI, LAESI, PADI, ASAP, DBDI, and ELDI [6 -11]. In DESI-MS, samples are analyzed by directing a pneumatically-assisted stream of charged microdroplets at the surface in the ambient...