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A novel inorganic nonmetallic material boron carbide (B4C) was applied in paper spray ionization to analyze organic molecules in both negative and positive modes. The utilization of B4C has led to a notable enhancement in signal responses for various molecules, including bisphenols and drugs, by approximately two to four times. The limit of detection (LOD) of bisphenol AF and nilotinib standard solutions can reach 1 and 0.5 μg/mL, respectively. Moreover, linear relationships for bisphenol AF was established within the concentration range of 1–100 μg/mL, exhibiting strong correlation coefficients. Recovery experiments for BPAF in water samples from the inlet and outlet of a sewage treatment plant, conducted without any pretreatment, achieved a maximum recovery rate of 98.8% and an RSD below 9.78%. [ABSTRACT FROM AUTHOR]

The absolute dating of documents is still one of the most important challenges for forensic document examiners (FDE). The potential difference between the date on a questioned document and the actual year of production of the used paper can be only 1 to 5 years. Until now, there was no analytical method with this accuracy available. This study demonstrates a method for an absolute dating of paper by using the 14C bomb peak and dating the starch in the paper. Accelerator mass spectroscopy (AMS) radiocarbon measurements were performed on starch extracts and cellulose fibers from 50 paper samples with known production year from 1950 to 2018. For most of the paper samples, the measured 14C concentration values in the starch extracts were highly correlated with the data of the 14C bomb peak calibration curve. The differences between the calibrated ages and the actual harvest years of the starch‐containing plants were only up to 3 years. The 14C concentration in the paper fibers showed a lower but significant correlation with the production year of the papers and can be used to support the dating results of the starch extracts. In order to secure the accuracy of the dating, aside from the radiocarbon measurements of the extracted starch other analytical methods or data are used, like a detailed chemical analysis of the paper composition including fiber composition and the spectroscopic analysis of the purity of the starch extracts. In practice, only starch extracts without contaminations are used for the paper dating. [ABSTRACT FROM AUTHOR]

We developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases. [ABSTRACT FROM AUTHOR]

Capturing short‐lived intermediates at the molecular level is key to understanding the mechanism and dynamics of chemical reactions. Here, we have developed a paper‐in‐tip bipolar electrolytic electrospray mass spectrometry platform, in which a piece of triangular conductive paper incorporated into a plastic pipette tip serves not only as an electrospray emitter but also as a bipolar electrode (BPE), thus triggering both electrospray and electrolysis simultaneously upon application of a high voltage. The bipolar electrolysis induces a pair of redox reactions on both sides of BPE, enabling both electro‐oxidation and electro‐reduction processes regardless of the positive or negative ion mode, thus facilitating access to complementary structural information for mechanism elucidation. Our method enables real‐time monitoring of transient intermediates (such as N,N‐dimethylaniline radical cation, dopamine o‐quinone (DAQ) and sulfenic acid with half‐lives ranging from microseconds to minutes) and transient processes (such as DAQ cyclization with a rate constant of 0.15 s−1). This platform also provides key insights into electrocatalytic reactions such as Fe (III)‐catalyzed dopamine oxidation to quinone species at physiological pH for neuromelanin formation. [ABSTRACT FROM AUTHOR]

Turmeric and ginger are extensively employed as functional ingredients due to their high content of curcuminoids and gingerols, considered the key bioactive compounds found in these roots. In this study, we present an innovative and fast method for the assay of curcuminoids and gingerols in different foods containing the two spices, with the aim of monitoring the quality of products from a nutraceutical perspective. The proposed approach is based on paper spray tandem mass spectrometry coupled with the use of a labeled internal standard, which has permitted to achieve the best results in terms of specificity and accuracy. All the calculated analytical parameters were satisfactory; accuracy values are around 100% for all spiked samples and the precision data result lower than 15%. The protocol was applied to several real samples, and to demonstrate its robustness and reliability, the results were compared to those arising from the common liquid chromatographic method. [ABSTRACT FROM AUTHOR]

Introduction: Distinguishing and categorizing the origin of garlic are highly significant, considering its widespread use as a flavoring agent. With billions of dollars annually in global trade, garlic is frequently susceptible to fraudulent practices. Methodology: Paper spray ionization mass spectrometry (PS‐MS) was employed to quickly analyze garlic samples from distinct geographic origins: China and Brazil. The so‐generated PS‐MS data were treated with metabolomic multivariate approaches, and the garlic samples from these different geographic regions were easily discriminated. Results: Brazilian garlic was characterized to contain higher levels of amino acids, such as arginine, proline, and valine, and organosulfur compounds, such as allicin, alliin, and l‐γ‐glutamil‐S‐allyl‐l‐cysteine, compared to Chinese garlic. The PS‐MS data were treated employing multivariate approaches, typically used in the metabolomics field, and this protocol was promptly able to discern among both types of samples. Conclusion: Hence, this combined strategy holds promise not only as an effective tool for the authentication of the geographical origin of garlic but also as a powerful means for biomarker discovery. [ABSTRACT FROM AUTHOR]

An unprecedented and direct PS‐MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS‐MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium‐contaminated, but the intensities were higher in the former samples. Moreover, long‐time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions. [ABSTRACT FROM AUTHOR]

The rise of fentanyl and fentanyl analogs in the drug supply pose serious threats to public health. Much of these compounds enter the United States through shipping routes. Here we provide a method for fentanyl screening and analysis that utilizes pressure‐sensitive adhesive (PSA) lined paper to recover drug residues from parcel‐related surfaces. The paper used is commercially available repositionable notes (also called post‐it or sticky notes). From this paper, mass spectra were obtained by paper spray‐mass spectrometry (PS‐MS), where PSA paper served as both a sampling and analysis substrate. Seven fentanyl‐related compounds were analyzed: fentanyl, 4‐anilino‐N‐phenethylpiperidine (4‐ANPP), N,1‐diphenethyl‐N‐phenylpiperidin‐4‐amine (phenethyl‐4‐ANPP), valerylfentanyl, 4‐fluoroisobutyrylfentanyl (4‐FIBF), carfentanil, and p‐fluorofentanyl. These compounds were recovered by PSA paper and identified by PS‐MS from packaging tape and plastic at 50 ng and from cardboard and shipping labels at 100 ng. The impact of cutting agents on PS‐MS analysis of fentanyl analogs was explored. No trends of analyte suppression were found at high concentrations of the cutting agents caffeine, diphenhydramine, and lidocaine when recovered from surfaces. A cartridge that required no precise cutting of PSA paper prior to sampling or analysis was evaluated for use in PS‐MS for fentanyl screening. Recovery and detection of fentanyl from plastic sheeting was demonstrated with this cut‐free cartridge. The cut‐free cartridge showed somewhat less consistency and lower analyte signal than the standard cartridge, but performance was suitable for potential screening applications. In combining PSA surface sampling with PS‐MS for drug screening, both sampling and detection of fentanyl‐related compounds is simple, rapid, and low‐cost. [ABSTRACT FROM AUTHOR]

Criminal practices in which an individual becomes vulnerable and prone to sexual assault after ingesting drinks spiked with doping substances have become a social concern globally. As forensic protocols require a multi‐tiered strategy for chemical evidentiary analysis, the backlog of evidence has become a significant problem in the community. Herein, a fast, sensible, and complementary dual analytical methodology was developed using a single commercial paper substrate for surface‐enhanced Raman spectroscopy (SERS) and paper spray mass spectrometry (PS‐MS) analysis to identify psychotropic substances added to alcoholic beverages irrefutably. To study and investigate this criminal practice, pharmaceutical formulations containing distinct psychotropic substances (zolpidem, clonazepam, diazepam, and ketamine) were added to drinks typically consumed at parties and festivals (Pilsen beer, açaí Catuaba®, gin tonic, and vodka mixed with Coca‐Cola Zero®). A simple liquid–liquid extraction with a low‐temperature partitioning (LLE‐LTP) procedure was applied to the drinks and effectively minimized matrix effects. As a preliminary analysis, SERS spectra combined with Hierarchical Clustering Analysis (HCA) provided sufficient information to investigate the samples further. The presence of the protonated species for the psychotropic substances in the spiked drinks was readily verified in the mass spectra and confirmed by tandem mass spectrometry. Finally, the results demonstrate the potential of this methodology to be easily implemented into the routine of forensic laboratories and to be further employed at harm reduction tends at parties and festivals to detect contaminated beverages promptly and irrefutably as an efficient tool to prevent such crimes. [ABSTRACT FROM AUTHOR]

Paper spray chemical ionization (PSCI) combined with mass spectrometry has been proposed as a sensitive method for the analysis of nonpolar aromatic compounds; however, the mechanism behind PSCI is not well understood. In the present study, the evidence for the occurrence of corona discharge is provided and its mechanism is proposed. Photographs taken with a highly sensitive camera evidently demonstrate the occurrence of corona discharge at the end of the triangular shape tip when a nonpolar solvent such as hexane was used at an applied potential of 6–7 kV. Nevertheless, corona discharge was not observed in the presence of a polar solvent. The occurrence of the corona discharge was attributed to charge accumulation in the dielectric layer generated by the nonpolar solvent on the fibers of the paper tip. Specifically, corona discharge was generated at the tip end when the charge approached a critical threshold. In the presence of a polar solvent, however, the dielectric layer was not generated and, hence, corona discharge was not observed. Based on this information, three nonpolar solvents were selected and their sensitivity for analyzing the phenanthrene and maltene fractions of crude oil was evaluated. Chlorobenzene provided the highest signal abundance; therefore, it was suggested as the optimum solvent for PSCI. Notably, the fundamental understanding of corona discharge in PSCI acquired in this study provides a basis for further improvement of this technique by way of surface modification. [ABSTRACT FROM AUTHOR]

Paper spray mass spectrometry (PS‐MS) is an ambient ionization technique that allows for rapid and direct mass spectrometry analysis for a wide range of chemical compounds due to its portability, little to no sample preparation, and cost‐effective materials. As applications with this technique continue to expand, the identification and discrimination of bacteria at the strain level remain a promising avenue for researchers. Although studies in the past demonstrated the applicability of PS‐MS to discriminate bacteria at the strain level, no one has reported the strain‐level differentiation of actinobacteria without using solvent for PS‐MS. Hence, this study demonstrates that optimization of PS‐MS permits the investigation and differentiation of the metabolic profiles of actinobacteria without the need for solvents, diminishing the potential for sample contamination and consequently increasing the versatility of this technique. In doing so, strains of actinobacteria (CAAT P5–21, CAAT P5–16, CAAT 8–25, CAAT P8–92, and CAAT P11–13) were grown and transferred to produce a crude growth medium. The supernatant was used for the PS‐MS analyses using a Thermo Scientific LTQ mass spectrometer. Multivariate statistical analysis, including principal component analysis (PCA) and hierarchal cluster analysis (HCA), was employed to chemically distinguish the strains of bacteria. As a result, each strain of actinobacteria could be visually differentiated based on their metabolic profile. These findings demonstrate the practicability of using a liquid medium as an alternative to many other organic solvents when analyzing bacteria, making PS‐MS a crucial addition to a microbiologist's research toolkit. [ABSTRACT FROM AUTHOR]

Rationale: The burgeoning concern of N‐nitrosamine (NAM) contamination found in various pharmaceutical compositions has increased the demand for rapid and reliable screening methods to better assess the breadth of the problem. These carcinogenic compounds are also found in food, water, and soil, and they have been used in poison‐related homicides. Methods: A combination of complementary, ambient ionization methods, paper spray ionization (PSI) and filter cone spray ionization (FCSI)‐mass spectrometry (MS), was characterized towards trace‐level residue screening of select NAMs (e.g., N‐nitrosodimethylamine, N‐nitrosodiethylamine, N‐nitrosodibutylamine) directly from complex and problematic matrices of interest, including prescription and over‐the‐counter tablets, drinking water, soil, and consumable goods. Spectral data for analyte confirmation and detection limit studies were collected using a Thermo LCQ Fleet ion trap mass spectrometer. Results: PSI‐MS and FCSI‐MS readily produced mass spectral data marked by their simplicity (e.g., predominantly protonated molecular ions observed) and congruence with traditional electrospray ionization mass spectra in under 2 min. per sample. Both methods proved robust to the complex matrices tested, yielding ion signatures for target NAMs, as well as active pharmaceutical ingredients for analyzed tablets, flavorants inherent to food products, etc. Low part‐per‐million detection limits were observed but were shown dependent on sample composition. Conclusions: PSI‐MS and FCSI‐MS were successful in detecting trace‐level NAMS in complex liquid‐ and solid‐phase matrices with little to no prior preparation. This work suggests that these methodologies can provide a means for assessing problematic pharmaceutical adulterants/degradants for expedited quality control, as well as enhancing environmental stewardship efforts and forensic investigations. [ABSTRACT FROM AUTHOR]

Hypericum perforatum L. (St. John's wort) is one of the world's most consumed medicinal plants for treating depression and psychiatric disorders. Counterfeiting can occur in the medicinal plant trade, either due to the lack of active ingredients or the addition of substances not mentioned on the labels, often without therapeutic value or even harmful to health. Hence, 43 samples of St. John's wort commercially acquired in different Brazilian regions and other countries were analyzed by paper spray ionization mass spectrometry (PS‐MS) and modeled by principal component analysis. Hence, samples (plants, capsules, and tablets) were extracted with ethanol in a solid–liquid extraction. For the first time, PS‐MS analysis allowed the detection of counterfeit H. perforatum samples containing active principles typical of other plants, such as Ageratum conyzoides and Senna spectabilis. About 52.3% of the samples were considered adulterated for having at least one of these two species in their composition. Furthermore, out of 35 samples produced in Brazil, only 13 were deemed authentic, having only H. perforatum. Therefore, there is a clear need to improve these drugs' quality control in Brazil. [ABSTRACT FROM AUTHOR]

Adsorbents play a significant role in enhancing the analytical sensitivity of target analytes in complex samples by mitigating matrix effects. In our recent report, ZnO stood out among various adsorbents to determine target therapeutic drugs in complex biological matrices when applied for portable paper‐based electrospray ionization mass spectrometry (PPESI‐MS). However, the influence of the morphology of ZnO on the performance of PPESI‐MS is elusive. Herein, different morphologies of ZnO particles were prepared via co‐precipitation or ultrasonic methods, and their capability to determine different therapeutic drugs in serum were systemically investigated. The results demonstrated that flower‐shaped ZnO gave a superior capacity, and its analysis sensitivity was 2.9–12.8‐fold higher than those achieved with other ZnO morphologies. Further characterization revealed that the unique performance of flower‐shaped ZnO was closely associated with its favorable desorption behavior to drugs, small spray plume, and few spray emitters at the tip of coated paper substrate. To illustrate the potential of flower‐shaped ZnO, its coated paper was used as a substrate for the determination of various drugs in complex matrices such as serum, and a limit of detection as low as 2 pg mL−1 was achieved. The corresponding recoveries ranged from 93.2% to 107.2%. The developed protocol is promising in high‐sensitivity analysis of target drugs in complex sample matrices. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray (PS) is a simple and innovative ambient ionization technique for mass spectrometry (MS) analysis. Under PS‐MS conditions, chemical reactions, which usually occur slowly on a bulk scale, are accelerated. Moreover, the formation of products and transient species can be easily monitored. In this manuscript, reactions between phthalic anhydride and diamines were conducted and monitored using a PS‐MS platform. The reaction products (phthalimides) have many pharmaceutical applications, but their traditional syntheses can take hours under reflux, requiring laborious purification steps. Methods: In situ reactions were performed by dropping methanolic solutions of phthalic anhydride and diamines on a triangular paper. The analyses were achieved by positioning the triangle tip in front of the mass spectrometer entrance, whereas a metal clip was attached to the triangle base. After adding methanol to the paper, a high voltage was applied across the metal clip, and the mass spectra were acquired. Results: The intrinsic reactivity of alkyl and aromatic diamines was evaluated. The carbon chain remarkably influenced the reactivity of aliphatic diamines. For aryl diamines, the ortho isomer was the most reactive. Moreover, for aryl amines with electron‐withdrawing substituents, no reaction was noticed. Conclusions: Taking advantage of the unique characteristics of PS‐MS, it was possible to investigate the intrinsic reactivity of model alkyl (ethylene versus propylene) and aryl (o‐phenylene versus m‐phenylene and p‐phenylene) diamines towards phthalic anhydride. Some crucial parameters that affect the intrinsic reactivity of organic molecules, such as isomerism, intramolecular interaction, and conformation, were easily explored. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray mass spectrometry (PS‐MS) was used to analyze and quantify ampicillin, a hydrophilic compound and frequently utilized antibiotic. Hydrophilic molecules are difficult to analyze via PS‐MS due to their strong binding affinity to paper substrates and low ionization efficiency, among other reasons. Methods: Solvent and paper parameters were optimized to increase the extraction of ampicillin from the paper substrate. After optimizing these key parameters, a Resolution IV 1/16 fractional factorial design with two center points was employed to screen eight different design parameters simultaneously. Results: Pore size, sample volume, and solvent volume were the most significant factors affecting average peak area under the curve (AUC) and the signal‐to‐blank (S/B) ratio for the 1 μg/mL ampicillin calibrant. After optimizing the key parameters, a linear calibration curve with a range of 0.2 μg/mL to 100 μg/mL was generated (R2 = 0.98) and the limit of detection (LOD) and lower limit of quantification (LLOQ) were calculated to be 0.07 μg/mL and 0.25 μg/mL, respectively. Conclusions: The statistical optimization procedure undertaken here increased the mass spectral signal intensity by more than a factor of 40. This statistical method of screening followed by optimization experiments proved faster and more efficient, and produced more drastic improvements than typical one‐factor‐at‐a‐time experiments. [ABSTRACT FROM AUTHOR]

This paper reports the use of paper spray mass spectrometry (PS‐MS) combined with chemometric models to analyze seized samples of anabolic steroids. Because many forensic laboratories typically demand high‐throughput analysis for this type of sample, we developed a quicker and simpler alternative analytical method for routine analysis with minimal sample preparation. Oily samples (n = 39) resulting from seizures carried out by Brazilian Federal and State Police units were selected for this study. These samples were analyzed by PS‐MS in the positive ion mode and full scan (50–1000 m/z), providing spectra containing patterns of the respective active ingredients present in each product. A principal component analysis (PCA) model was built, which discriminated samples mainly according to their active ingredients and allowed to detect and characterize some cases of product counterfeiting. The variable selection method ordered predictors selection was employed jointly with PCA to improve sample cluster separation and to provide model simplification. The final PCA model was built with three principal components and using only 28 spectral variables. This model accounted for 69.82% of the variance and discriminated samples according to their specific active ingredients. [ABSTRACT FROM AUTHOR]

Food safety and authenticity analysis play a pivotal role in guaranteeing food quality, safeguarding public health, and upholding consumer trust. In recent years, significant social progress has presented fresh challenges in the realm of food analysis, underscoring the imperative requirement to devise innovative and expedient approaches for conducting on‐site assessments. Consequently, cellulose paper‐based devices (PADs) have come into the spotlight due to their characteristics of microchannels and inherent capillary action. This review summarizes the recent advances in cellulose PADs in various food products, comprising various fabrication strategies, detection methods such as mass spectrometry and multi‐mode detection, sampling and processing considerations, as well as applications in screening food safety factors and assessing food authenticity developed in the past 3 years. According to the above studies, cellulose PADs face challenges such as limited sample processing, inadequate multiplexing capabilities, and the requirement for workflow integration, while emerging innovations, comprising the use of simplified sample pretreatment techniques, the integration of advanced nanomaterials, and advanced instruments such as portable mass spectrometer and the innovation of multimodal detection methods, offer potential solutions and are highlighted as promising directions. This review underscores the significant potential of cellulose PADs in facilitating decentralized, cost‐effective, and simplified testing methodologies to maintain food safety standards. With the progression of interdisciplinary research, cellulose PADs are expected to become essential platforms for on‐site food safety and authentication analysis, thereby significantly enhancing global food safety for consumers. [ABSTRACT FROM AUTHOR]

Accurate quantification of disease‐signature microRNAs (miRNAs) in biomedical samples is in high demand for clinical diagnosis but still challenging because of the low abundance of miRNAs and complicating interferences in the milieus. Here, we report a multi‐amplification strategy based on paper‐spray mass spectrometry (PS MS) for the analysis of miRNAs in blood. A toehold‐mediated DNA‐strand‐displacement reaction (TSD) is employed to amplify the signal chain and to ensure the specificity. The signal chain is then cleaved by UV light to release signal molecules for detection. Moreover, the paper spray method can efficiently filter out interfering substances in the blood and further enhance the sensitivity of detection. This concept is successfully demonstrated in the prototypical detection of the cancer biomarker miRNA‐141 in blood and serum. The proposed TSD‐PS MS approach provides an efficient method for the sensitive detection of oligonucleotides at low concentration in complicated milieus. [ABSTRACT FROM AUTHOR]

Introduction: Drug checking services for harm reduction and overdose prevention have been implemented in many jurisdictions as a public health intervention in response to the opioid overdose crisis. This study demonstrates the first on‐site use of paper spray mass spectrometry for quantitative drug checking to address the limitations of current on‐site drug testing technologies. Methods: Paper spray mass spectrometry was used to provide on‐site drug checking services at a supervised consumption site in the Downtown Eastside of Vancouver, British Columbia, Canada during a 2‐day pilot test in August 2019. The method included the targeted quantitative measurement of 49 drugs and an untargeted full scan to assist in identifying unknown/unexpected components. Results: During the pilot, 113 samples were submitted for analysis, with 88 (78%) containing the client expected substance. Fentanyl was detected in 45 of 59 expected fentanyl samples, and in 50 (44%) samples overall at a median concentration of 3.6% (w/w%). The synthetic precursor of fentanyl, 4‐anilino‐N‐phenethyl‐piperidine (4‐ANPP), was found in 74.0% of all fentanyl samples at a median concentration of 2.2%, suggesting widespread poor manufacturing practices. Etizolam was detected in 10 submitted samples anticipated to be fentanyl at a median concentration of 2.5%. No clients submitting these samples expected etizolam or a benzodiazepine in their sample. In three instances, it was co‐measured with fentanyl, and in seven cases it was detected alone. Discussion and Conclusions: The quantitative capabilities and low detection limits demonstrated by paper spray mass spectrometry offer distinct benefits over existing on‐site drug checking methods and harm reduction services. [ABSTRACT FROM AUTHOR]

In this work, we synthesized diethylamino substituted pyrazolo imine (3) fluorescent probe for recognition of Hg2+ion.The sensor probe 3 can detect Hg2+ by colorimetric method, and there is a 10‐fold enhancement in fluorescence response. When the fluorescent probe bound with Hg2+ ion, turn‐on fluorescence was observed via the coordination. Probe 3 has an excellent selectivity toward Hg2+ in the CH3CN/H2O (8:2, v/v) solution with low limit of detection and high binding association constant of 551 parts per billion (ppb) and 6.6067 × 106 m−1 for 3+Hg2+, respectively. Furthermore, the formation of 3+Hg2+ complex with 1:1 binding mode was evidenced by Job's plot, 1H NMR spectroscopy and Mass analysis. In addition, probe 3 is a feasible option to detect Hg2+ in various sources of water samples. Bio‐imaging experiments have demonstrated that probe 3 can be used to monitor Hg2+ in Escherichia coli bacterial cell. The sensor 3 was also used for paper strip application to detect Hg2+ ion. [ABSTRACT FROM AUTHOR]

A bifunctional fluorescence probe (PCT) based on 2‐Hydroxy‐1‐naphthaldehyde and thiosemicarbazide was developed. The probe PCT can selectively detect Ag+ and Al3+ with two clear fluorescence color changes from colorless to yellow and blue violet, respectively. According to the Job's plots and mass spectrum, the binding stoichiometry of the probe PCT with Ag+ and Al3+ was 1 : 1, respectively. Moreover, the detection limit values of PCT for Ag+ and Al3+ in neutral solutions were 1.97 and 1.63 nM and these values were remarkably lower than allowed Ag+ and Al3+ concentrations in potable water determined by the World Health Organization (WHO). The distinct different binding mode were elucidated in this paper. Finally, the probe PCT has been used successfully for the detection of Ag+ and Al3+ in real water samples, logic gate and test paper. [ABSTRACT FROM AUTHOR]

Recent advancements in the sensitivity of chemical instrumentation have led to increased interest in the use of microsamples for translational and biomedical research. Paper substrates are by far the most widely used media for biofluid collection, and mass spectrometry is the preferred method of analysis of the resultant dried blood spot (DBS) samples. Although there have been a variety of review papers published on DBS, there has been no attempt to unify the century old DBS methodology with modern applications utilizing modified paper and paper‐based microfluidics for sampling, storage, processing, and analysis. This critical review will discuss how mass spectrometry has expanded the utility of paper substrates from sample collection and storage, to direct complex mixture analysis to on‐surface reaction monitoring. [ABSTRACT FROM AUTHOR]

Paper spray ionization mass spectrometry (PSI‐MS) was used to detect a variety of species of hafnium and zirconium present in an aqueous acid solution containing NO3− and F− anions. This solution mimetics the acid waters used in separation/extraction processes. Hence, the information provided by PSI‐MS is combined with the results achieved from DFT calculations to confirm the nature and stability of each species. In the adopted experimental conditions, Zr(IV) appears coordinated with F−, NO3− and H2O to generate mainly the dimer [Zr2F3OH(NO3)2(H2O)5]2+, among other complexes, with remarkable thermodynamic stability (−48.7 kcal mol−1). On the other hand, Hf(IV) emerges predominantly coordinated with NO3− and F− anions. The hafnium monomers [HfF4NO3]− and [HfF3(NO3)2]− have thermodynamic stability related to the electron pairing of the valence layer. In the gas phase, the fluoroanions of Zr(IV) demonstrated a high electronic affinity and free energy via DFT (−156.7 kcal mol−1) correlating thermodynamic stability to the experimental (−47 kcal mol−1), for the formation reaction of [ZrF5]−. Besides, the presence of fluoride and nitrate in the reaction mixture induces the formation of dimers connected in μ2‐F bridges, with coordination 7 and 8 of the central atom. Finally, the results described herein are promising studies of chemical speciation of cationic metals in an aqueous environment, a challenging subject whose importance will grow in the coming years. [ABSTRACT FROM AUTHOR]

Rationale: The effort to make fake documents look real leads to the use of crickets and beverages to produce artificially aged papers, as land titles, based on yellowing caused by the use of these methods. An old practice in Brazil, called "cricketing", has led to the misappropriation of Brazilian land using these documents. We propose a rapid, simple, instantaneous and non‐destructive method to identify artificially aged papers by easy ambient sonic‐spray ionization mass spectrometry (EASI‐MS) analysis. Methods: Three typical aging procedures were used to obtain artificially aged papers using coffee, cola drink, and crickets, with the papers being analyzed by EASI‐MS. Multivariate statistical analyses were performed on the data to find the sample groups and to study the most relevant ions of each ageing procedure. High‐resolution MS (HRMS) was used to obtain the exact masses and attribute formulae to relevant ions present in the samples. Results: The combination of EASI‐MS and multivariate statistical analyses allowed us to identify the most relevant ions to classify the adulteration of documents and HRMS identified most of these relevant ions. TMS fingerprinting in combination with multivariate analysis also demonstrated that this approach can qualitatively differentiate all the examined paper samples. Conclusions: We developed a cheap, fast and easy method that can help to elucidate counterfeit documents that have been artificially aged, helping to identify chemical additives and one that can be used in forensic laboratories. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray offers a rapid screening test without the need for sample preparation. The incomplete extraction of paper spray allows for further testing using more robust, selective and sensitive techniques such as liquid chromatography/mass spectrometry (LC/MS). Here we develop a two‐step process of paper spray followed by LC/MS to (1) rapidly screen a large number of samples and (2) confirm any disputed results. This demonstrates the applicability for testing medication adherence from a fingerprint. Methods: Following paper spray analysis, drugs of abuse samples were analysed using LC/MS. All analyses were completed using a Q Exactive™ Plus Orbitrap™ mass spectrometer. This two‐step procedure was applied to fingerprints collected from patients on a maintained dose of the antipsychotic drug quetiapine. Results: The extraction efficiency of paper spray for two drugs of abuse and metabolites was found to be between 15 and 35% (analyte dependent). For short acquisition times, the extraction efficiency was found to vary between replicates by less than 30%, enabling subsequent analysis by LC/MS. This two‐step process was then applied to fingerprints collected from two patients taking the antipsychotic drug quetiapine, which demonstrates how a negative screening result from paper spray can be resolved using LC/MS. Conclusions: We have shown for the first time the sequential analysis of the same sample using paper spray and LC/MS, as well as the detection of an antipsychotic drug from a fingerprint. We propose that this workflow may also be applied to any type of sample compatible with paper spray, and will be especially convenient where only one sample is available for analysis. [ABSTRACT FROM AUTHOR]

We developed a highly efficient and low‐cost organic solvents‐resistant microfluidic paper‐based analytical device (μPAD) coupled with paper spray mass spectrometry (PS‐MS) for quantitative determination of C18‐ceramide as a prognostic biomarker for several diseases. Several models of μPAD patterns have been examined to select the most resistant and efficient microchannel barriers, which can provide continuous spray at ionization zone and prevent "coffee ring" effect. Moreover, the developed μPAD has enabled the analysis of low concentration of C18‐ceramide because of the maximum supply of deposited analyte through microchannel. The MS results confirmed the formation of doubly and singly charged metal ion complexes between ceramide and different metal ions. Notably, the complexation that occurs between lithium ions and C18‐ceramide showed a high relative abundance compared with other formed complexes. Taking into account the relative abundance of complex [Cer + Li]+ at 572.8 m/z, it can be considered as a stable ion and therefore be used for the analysis of C18‐ceramide at low concentrations. Complexation of C18‐ceramide and lithium confirmed with quantum chemical calculations. The proposed method represents good linearity with a regression coefficient of 0.9956 for the analysis of C18‐ceramide and reaches a limit of detection to 0.84 nM. It has been adapted successfully for practical application in human serum samples with high recovery values in range of 92%–105%. The developed μPAD‐MS technique provides clear advantages by reducing the experimental steps and simplifying the operation process and enables to identify subnanomolar concentration of C18‐ceramide in human serum samples. [ABSTRACT FROM AUTHOR]

Paper spray ionization (PSI) is a direct, fast, and low-cost ambient ionization technique which may have clinical utility for qualitative and quantitative analysis of therapeutic drugs and metabolites from patient specimens. We developed and validated a PSI-mass spectrometry (PSI-MS/MS) method according to the US-FDA guidelines for bioanalytical studies to measure the prostate cancer drug abiraterone directly from patient plasma. The established linearity range was 3.1-156.8 ng/mL with a precision (%CV) and an accuracy (%) range of 0.5-10.7 and 93.5-103.2, respectively. The mean internal standard normalized matrix factor for abiraterone was just below 1 with highest %CV of 10.2 at the low-level quality control. In benchmarking the performance of this assay against a published LC-MS/MS assay, we showed they were mostly equivalent, with the exception of accuracy with clinical samples. We found the quantitative values observed for abiraterone measured directly from patient plasma using PSI-MS/MS showed positive bias. Upon investigation, we concluded the increased values were due to summed quantitation of isomeric abiraterone conjugates and metabolites which are separable by LC-MS/MS, but not with the current PSI-MS/MS configuration. Despite demonstrating the utility of PSI-MS/MS for rapid bioanalysis, this study also highlighted a limitation encountered with the direct analysis of abiraterone in clinical samples. [ABSTRACT FROM AUTHOR]

Rationale: The loquat (Eriobotrya japonica Lindl.) is a fruit tree that has been used in Chinese medicine for thousands of years for the treatment of various diseases. The loquat leaf extracts contain several bioactive compounds with antioxidant and antimicrobial properties, and identification of these substances using quick and simple methods has been an analytical trend. Methods: The influence of dehydration of loquat leaves (without drying, at 40_C, and at 60_C), the type of solvent (ethanol and methanol), and the method of extraction (shaking and ultrasound) on obtaining extracts containing phenolic compounds and substances with antioxidant and antimicrobial properties was evaluated. The chemical constituents of an extract were identified using paper spray mass spectrometry (PS-MS). Results: The extract obtained from the dehydrated leaves at 40_C presented the best results. The extracts obtained from these leaves and with ethanol had the highest values of total phenolics and antioxidant activities, but the methanolic extract subjected to ultrasound had the highest levels of chlorogenic, caffeic, and ellagic acids. All extracts evaluated inhibited the growth of Staphylococcus aureus. Using the PS-MS technique, it was possible to identify the presence of 49 substances such as organic acids, phenolic acids, flavonoids, sugars, quinones, and terpenes. Conclusions: In general, extracts of dehydrated leaves at 40_C and extracted with ethanol using ultrasound can be considered a good source of bioactive compounds with potential applications as functional ingredients or additives in the food and pharmaceutical industries. PS-MS was demonstrated to be a simple and ultrafast technique to obtain the chemical profile of the loquat leaf extract. [ABSTRACT FROM AUTHOR]

Rationale: Smoking is responsible for one in five deaths around the world. Thus, governments have been trying to reduce the number of active smokers by increasing taxes on products. This scenario creates a new problem by raising the consumption of illegally traded cigarettes, which are often seized and analyzed by police forces. Methods: Legal and illegal cigarette samples were extracted and analyzed using paper spray ionization mass spectrometry (PS-MS). The mass spectrometer was set to operate in full-scan positive ion mode to yield representative chemical profiles of each sample. The results were used to build a chemometric model using partial least squares discriminant analysis (PLS-DA) to discriminate between both sets of samples, i.e. legal and illegal. Results: The PS-MS procedure was fast, simple and efficient, yielding high-quality and reproducible mass spectra with a very good signal-to-noise ratio. Even though all samples displayed visually indistinguishable mass spectra, the PS-MS data handled by the PLS-DA approach furnished a model that reached sample classification with rates of 100% and 80% for the training and validation sets, respectively. Conclusions: A novel methodology was successfully developed associating the PSMS technique with chemometric analysis to differentiate between legal and illegal cigarettes. The PS-MS technique proved to be adequate for obtaining fingerprints of such types of samples despite high complexity, and a PLS-DA model was successfully constructed achieving 82.1% accuracy. [ABSTRACT FROM AUTHOR]

Reactive ionization with atmospheric pressure ionization (API) methods have been utilized for mass spectrometry (MS) to enhance ionization efficiency of an analyte, to recognize a specific functional group of an analyte, and to investigate reaction pathways or intermediates for a certain in situ reaction. Paper spray ionization (PSI) is one of the major API techniques for reactive ionization. In reactive PSI, one of the reactants is usually spotted onto a paper tip and the other reactant is delivered through a spraying solution. After in situ reaction, reaction products are transported to the end of the tip and ionized. In this study, we investigated reactions between isothiazolinones (ITs) and cysteamine (CA) by reactive PSI MS. An IT is a heterocyclic compound that has a conjugated ketone moiety and used as a biocide or a preservative. CA is a stable aminothiol that is often used as a bifunctional covalent modifier. Through reactive PSI MS of ITs with CA, we found that a covalent modification of an IT by CA was possible and sensitivities for ITs were improved compared to conventional PSI MS of ITs that did not employ CA. In addition, possible reaction pathways between ITs and CA during reactive PSI were suggested although we could not confirm a specific reaction pathway in the current study. [ABSTRACT FROM AUTHOR]

Paper spray ionization, one of the ambient mass spectrometry technologies, has been developed to characterize the content of drugs in various complex matrixes including urine, whole blood, dissolution solutions, and so on. An isotopically labeled compound as internal standard is often used in quantitative paper spray ionization experiments. But high cost and difficult to access impede the application of this type of internal standards. Application of non‐isotopically labeled compounds as internal standards will make this technology more prevalent. In this paper, we explored the application of finasteride impurity as the internal standard in paper spray ionization–mass spectrometry to measure the dissolution content of finasteride tablets. The new method was optimized and the results were compared to those from high‐performance liquid chromatography. The whole analysis time was several minutes and limit of detection for finasteride was around 4.8 ng/mL. The results from paper spray ionization–mass spectrometry were similar to those from high‐performance liquid chromatography. Combination of paper spray ionization–mass spectrometry and non‐isotopically labeled internal standard renders a new method to analyze drug dissolution content with high specificity, low limit of detection, and simple sample preparation within short time period. [ABSTRACT FROM AUTHOR]

Rationale Significant advances have been made in the preparation of different morphologies of magnesium oxide (MgO), but the relationship between MgO morphology and its interactions with therapeutic drugs is rarely studied. Herein, we investigated the interactions between different morphologies of MgO and therapeutic drugs using paper spray mass spectrometry. Methods Different morphologies of MgO including trapezoidal, needle-like, flower-like and nest-like structures were prepared through a facile precipitation method. The as-obtained MgO particles were then coated onto the surface of filter paper via vacuum filtration strategy. The coated papers with different morphologies of MgO were used as the substrates for paper spray mass spectrometry to explore the interactions between different MgO and therapeutic drugs. Results Through investigating the interactions between different morphologies of MgO coated papers and therapeutic drugs, it demonstrated that, in contrast to the trapezoidal, needle-like and nest-like MgO coated papers, different drugs in dried blood spots (DBS) were more favourably eluted off from the paper coated with flower-like MgO due to its weaker surface basicity. Also, the signal intensities of different drugs during paper spray were highly dependent on their elution behaviours. Conclusions Paper spray mass spectrometry (MS) provides an avenue to elaborate the surface properties of MgO with different structures. The surface basicity of MgO played a crucial role in determining the elution behaviours of therapeutic drugs in DBS, and a more favourable elution behaviour tended to result in a higher MS signal. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Fentanyl and related psychoactive substances are at the forefront of the opioid overdose crisis, for which a complete solution is not immediately obvious. Drug testing for harm reduction may be an effective approach to both reduce overdoses and importantly, engage people who use drugs (PWUD) with the medical system. Paper spray mass spectrometry (PS‐MS) is an ambient ionization strategy that is uniquely suited to address this complicated analytical task. This perspectives article presents the merits of PS‐MS, with a focus upon the current state of its use as a candidate drug checking strategy for harm reduction. PS‐MS is inherently sensitive and selective, with detection limits in the picogram range. It requires small drug samples (~1 mg) for quantitative drug testing, critical to encourage pre‐consumption measurements by PWUD in the context of a harm reduction strategy. Calibrations obtained in surrogate drug matrices containing highly concentrated primary drugs demonstrate comparable sensitivities, a wide calibration range, and minimal matrix effects. PS‐MS can be interfaced with high‐resolution MS for non‐targeted analysis, allowing the identification of novel psychoactive substances as they appear in street drugs. Individual quantitative PS‐MS measurements for drug testing can be done in 1 minute or less, resulting in high sample throughput. Significant advancement in mass spectrometer miniaturization and mobilization has concomitant benefits for direct, on‐site drug checking, such as reduced cost, simplified maintenance and ease of use by less skilled operators. While PS‐MS technology continues to rapidly advance, it is our opinion that PS‐MS can be utilized as an effective tool for harm reduction in the opioid overdose crisis. [ABSTRACT FROM AUTHOR]

Water samples were collected on three dates at 24 sites influenced by effluent from Georgia-Pacific's Palatka Pulp and Paper Mill Operation, a bleached and unbleached kraft mill near Palatka, Florida, USA. The sampling sites were located within the mill retention ponds, Rice Creek, and the St. John's River. Samples were analyzed by gas chromatography--mass spectrometry for abietic, dehydroabietic, and isopimaric acids, all of which are potentially toxic by-products of pulp production. Isopimaric acid concentrations greater than 12 mg/L were measured at the mill's effluent outfall but were less than 20 µg/L at the end of Rice Creek. This result indicates that the waters of Rice Creek provide dilution or conditions conducive for degradation or sorption of these compounds. Large differences in resin acid concentrations were observed between sampling events. In two sampling events, the maximum observed concentrations were less than 2 mg/L for each analyte. In a third sampling event, all of the compounds were detected at concentrations greater than 10 mg/L. Data from the three sample dates showed that resin acid concentrations were below 20 µg/L before the confluence of Rice Creek and the St. John's River in all cases. [ABSTRACT FROM AUTHOR]

Rationale: The ability to detect and quantify the presence of specific inorganic elements and complexes is essential for environmental monitoring and nuclear safeguards applications. In this work, paper spray ionization mass spectrometry was used for the rapid chemical and isotopic characterization of trace inorganic species collected on cotton swipe substrates. The direct analysis of cotton swipes using this ambient ionization technique led to fast sample analysis that retained original chemical information of the source material with minimal sample preparation. Methods: Mass spectra were collected with an atmospheric pressure ionization, high‐resolution mass spectrometer for solutions containing uranyl acetate, uranyl chloride, uranyl nitrate, and uranyl tri‐n‐butylphosphate complexes. Gadolinium nitrate was used as an internal standard for the quantitative analysis of uranium. To demonstrate the ability to characterize inorganic contaminants in the presence of uranium, a multi‐element inorganic standard containing U, Bi, Pb, Cd, Fe, and Zn was deposited onto cotton substrates and directly analyzed without purification. Results: All elements doped on the cotton substrate were detected with strong signal‐to‐noise ratios (ca 1000 for UO2+ on multi‐element doped swipes) and high integrated intensities (>105 counts) from collection periods of approximately 1 min. Limits of detection were determined to be approximately 94 ng for UO2+ and uranyl acetate through the measurement of ppb level solutions. Conclusions: The rapid analysis of uranium and other inorganic‐containing samples while still retaining original chemical information (e.g. uranyl complexation) was demonstrated. Qualitative detection and speciation were achieved in less than 1 min of analysis. For uranium isotopic quantitation, longer accumulations (>15 min) can be sustained to improve the accuracy of minor 235U isotopic abundance measurements to approximately 1% error. [ABSTRACT FROM AUTHOR]

Rationale: The decolouration of brilliant blue FCF by the action of titanium dioxide (TiO2) under ultraviolet (UV) exposure has been recently reported as the basis of a paper‐based sensor for monitoring UV sun exposure. The mechanism of brilliant blue FCF photodegradation in the presence of the photocatalyst and the resulting photoproducts are thus far unknown. Methods: The UV‐initiated photodegradation of brilliant blue FCF in the presence of TiO2 for both the aqueous and the solid state was investigated. Degradation in the solid state was observed using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐MS). Decomposition of the dye in the aqueous state was analyzed using liquid chromatography/mass spectrometry (LC/MS) and ultraviolet–visible (UV–Vis) spectroscopy. Results: After UV radiation exposure, the brilliant blue FCF base peak [M1 + NH4]+ (m/z calc. 766.194 found 766.194) decreased in the LC/MS chromatogram with a concomitant appearance of BB‐FCF decomposition products involving the sequential loss of the N‐ethyl and N‐methylbenzene sulfonate (MBSA) groups, assigned as [M2 + H]+ (‐MBSA, calc. 579.163 found 579.162), [M3 + H]+ (‐MBSA, −Et, calc. 551.131 found 551.131), [M4 + H]+ (‐2MBSA, calc. 409.158 found 409.158), [M5 + H]+ (‐2MBSA, −Et, calc. 381.127 found 381.127). Ions [M2 + H]+ and [M3 + H]+ were also identified in the photodegradation products using MALDI‐MS. Observation by UV–Vis indicated a decrease in the solution absorbance maxima and an associated blue‐shift upon UV exposure in solution. Conclusions: The LC/MS analysis indicated two main oxidation processes. The most obvious was attack of the N‐methylene, eliminating either ethyl or MBSA groups. The presence of the hydroxylated decomposition product M13 ([M13 + H]+, calc. 595.157 found 595.157) supported this assignment. In addition, the detection of photoproduct M8, proposed to be 3‐((ethylamino)methyl)benzenesulfonic acid ([M8 + H]+, calc. 216.069 found 216.069), indicates an aryl‐oxidative elimination. The absence of the aryl‐hydroxy products normally expected to accompany the formation of M8 is proposed to be due to TiO2‐binding catechol‐like derivatives, which are then removed upon filtration. [ABSTRACT FROM AUTHOR]

Rationale: Paper spray (PS) has been developed as a method of choice for point‐of‐care analysis in many real cases, where its applications can be further expanded with delicate high‐throughput design. To achieve this goal, we developed a new PS regime, with the assembly of an induced high voltage into the ion source. Compared with regular DC high voltage, the newly developed setup is capable of high‐throughput, simple configuration and rapid switching between individual papers without complicated electric/mechanic design. Methods: A device of high‐throughput induced PS (IPS) was designed by using a two‐dimensional (2D) rotating platform equipped with a circular glass plate. The paper substrate was placed on the circular glass plate and separated from the electrode. The method avoids physical contact between the electrode and the sample. Charged droplets were generated at the paper tip once an induced high voltage was applied to a wet paper. Results: A relatively rapid analytical speed of 2.6 s per sample was achieved via IPS‐MS. Rapid quantification of amitriptyline (AMT) in complicated matrices was obtained within 1 min using an isotope internal standard method. Limits of detection for AMt in urine, FBS and blood were calculated to be 1.04, 0.84 and 1.33 ng/mL, respectively. In addition, high‐throughput IPS‐MS can be used for chemical reaction monitoring. Conclusions: We have demonstrated the versatility of high‐throughput IPS‐MS in ambient ionization, which successfully simplified the experimental installation and facilitated the experimental operation. Therefore, we believe that high‐throughput IPS‐MS analysis will be widely used for discovering drugs and screening reactions, and the present design has the potential for applications in paper chip‐MS analysis. [ABSTRACT FROM AUTHOR]

Rationale: Drug overdose deaths due to fentanyls and other novel psychoactive substances (NPS) are on the rise. The higher potencies of fentanyl analogs compared with morphine require new technologies to identify and quantitate NPS. Methods: Paper spray tandem mass spectrometry (MS/MS) and high‐resolution mass spectrometry were used to identify and measure fentanyl analogs as well as common drugs of abuse in urine samples from substance use disorder clinics. Ten‐microliter urine samples were deposited directly on paper spray cartridges previously loaded with internal standards, dried, and analyzed with no other sample treatment. Quantitative results were obtained using MS/MS. Individual drugs were identified using high‐resolution accurate mass spectrometry, and confirmed by data‐dependent MS/MS. Results: Calibration curves in urine were linear over a range of 0.5–50 ng/mL with R2 of 0.99 or better for eight representative fentanyl analogs. Cartridges preloaded with internal standards demonstrated satisfactory quantitative results compared with LC/MS. Direct identification and confirmation of fentanyl analogs and other common drugs of abuse in urine using high‐resolution accurate mass and MS/MS fragmentation were demonstrated at low picogram levels. Conclusions: Paper spray mass spectrometry can reliably identify and quantitate fentanyl analogs and other drugs of abuse in urine. Using paper spray cartridges as collection devices reduces exposure and transportation risks associated with biological fluids. Cartridges preloaded with labeled internal standards can be effective for targeted screening of fentanyl analogs and other drugs of abuse. [ABSTRACT FROM AUTHOR]

As the food and pharmaceutical industries move toward more sustainable forms of packaging, paper is experiencing somewhat of a comeback as a packaging material. However, by its very nature paper is rich in volatiles—both with and without significant olfactory impact. Human sensory analysis has long been the benchmark for determining that a product is fit for consumer application. However, sensory analysis is limited in its application due to the high per‐sample cost. Selected ion flow tube mass spectrometry (SIFT‐MS) is an instrumental approach that has potential to rapidly screen paper samples for both sensory and chemical composition attributes in a single broad‐spectrum and sensitive analysis of volatiles. In this study, a combined approach utilizing SIFT‐MS sample analysis with multivariate statistical data processing is evaluated for its ability to distinguish between samples of different paper composition (in particular, virgin, recycled, or mixed fibres), mill of origin (manufacturing mill), sensory odour intensity rating, and sensory odour note. Paper samples from four mills were analysed using instrumental and sensory methods, together with one pulp sample. The key discriminating volatiles varied depending on the classification model but typically included hydrogen sulfide, ethanol, acetone, hexanal, dimethyl sulfide, and formaldehyde. The pulp sample generally exhibited significantly higher concentrations of volatiles—especially methanol and hydrogen sulfide. Because it was so different, it was eliminated from certain models—in particular, for determination of the mill of origin. Chemical analysis with multivariate statistical processing exhibited near‐perfect classification of the fibre type and the mill of origin. Evaluation of instrumental prediction of odour intensity rating and odour note used multivariate statistical analysis to correlate sensory and instrumental results. It was found that concentration data provided superior classification of odour intensity rating and odour note than did odour activity values (compound concentrations divided by their human odour detection thresholds [ODTs]). This result is tentatively attributed to significant uncertainties introduced by literature ODTs and the method's limit of quantitation being higher than the ODT for several compounds. When using SIFT‐MS concentration data—when coupled with multivariate statistical data processing—this preliminary study demonstrates potential for rapid, instrumental determination of the odour intensity rating and odour note traditionally determined using human sensory analysis. [ABSTRACT FROM AUTHOR]

In this publication we work towards providing fast, sensitive and selective analysis of explosive compounds collected on swabs using paper spray mass spectrometry. We have (a) increased the size of the paper spray substrate to 1.6×2.1 cm for compatibility with current practise in swabbing for explosive material; (b) developed a method for determining a successful extraction of analyte from the substrate to reduce false negative events; and (c) expanded the range of analytes that can be detected using paper spray to include the peroxide explosive HMTD, as well as nitroglycerine (NG), picric acid (PA) and tetryl. We report the development of a 30 s method for the simultaneous detection of 7 different explosive materials using PS‐MS with detection limits below 25 pg, as well as detection of HMTD at 2500 pg, showing an improvement on previously published work. [ABSTRACT FROM AUTHOR]

RATIONALE The perfume market is growing significantly, and it is easy to find imitative fragrances of probably all types of perfume. Such imitative fragrances are usually of lower quality than the authentic ones, creating a possible threat for perfume companies. Therefore, it is important to develop efficient chemical analysis techniques to screen rapidly perfume samples. METHODS Electrostatic-spray ionization (ESTASI) was used to analyze directly samples sprayed or deposited on different types of paper. A linear ion trap mass spectrometer was used to detect the ions produced by ESTASI with a modified extended transfer capillary for 'sniffing' ions from the paper. RESULTS Several commercial perfumes and a model perfume were analyzed by ESTASI-sniffing. The results obtained by paper ESTASI-MS of commercial fragrances were compared with those obtained from ESI-MS. In addition, a commercial fragrance was first nebulized on the hand and then soaked up by blotting paper, which was afterwards placed on an insulating plate for ESTASI-MS analysis. Analysis of peptides and proteins was also performed to show that the paper ESTASI-MS could be used for samples with very different molecular masses. CONCLUSIONS Paper ESTASI-MS yields a rapid fingerprinting characterization of perfume fragrances, avoiding time-consuming sample-preparation steps, and thereby performing a rapid screening in a few seconds. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We have developed nanoparticle-embedded paper-spray mass spectrometry for studying three types of heterogeneously catalyzed reactions: 1) Palladium-nanoparticle-catalyzed Suzuki cross-coupling reactions, 2) palladium- or silver-nanoparticle-catalyzed 4-nitrophenol reduction, and 3) gold-nanoparticle-catalyzed glucose oxidation. These reactions were almost instantaneous on the nanocatalyst-embedded paper, which subsequently transferred the transient intermediates and products to a mass spectrometer for their detection. This in situ method of capturing transient intermediates and products from heterogeneous catalysis is highly promising for investigating the mechanism of catalysis and rapidly screening catalytic activity under ambient conditions. [ABSTRACT FROM AUTHOR]

The non-stick properties of parchment papers are achieved by polydimethylsiloxane (PDMS) coatings. During baking, PDMS can thus be extracted from the silicone-coated parchment into the baked goods. Positive-ion direct analysis in real time (DART) mass spectrometry (MS) is highly efficient for the analysis of PDMS. A DART-SVP source was coupled to a quadrupole-time-of-flightmass spectrometer to detect PDMS on the contact surface of baked goods after use of silicone-coated parchment papers. DART spectra from the bottom surface of baked cookies and pizzas exhibited signals because of PDMS ions of the general formula [(C2H6SiO)n + NH4]+ in the m/z 800-1900 range. [ABSTRACT FROM AUTHOR]

A novel approach for the rapid discrimination of bergamot essential oil from other citrus fruits oils is presented. The method was developed using paper spraymass spectrometry (PS-MS) allowing for a rapid molecular profiling coupled with a statistic tool for a precise and reliable discrimination between the bergamot complex matrix and other similar matrices, commonly used for its reconstitution. Ambient mass spectrometry possesses the ability to recordmass spectra of ordinary samples, in their native environment, without sample preparation or pre-separation by creating ions outside the instrument. The present study reports a PS-MS method for the determination of oxygen heterocyclic compounds such as furocoumarins, psoralens and flavonoids present in the non-volatile fraction of citrus fruits essential oils followed by chemometric analysis. The volatile fraction of Bergamot is one of the most known and fashionable natural products, which found applications in flavoring industry as ingredient in beverages and flavored foodstuff. The development of the presented method employed bergamot, sweet orange, orange, cedar, grapefruit and mandarin essential oils. PS-MS measurements were carried out in full scan mode for a total run time of 2 min. The capability of PS-MS profiling to act as marker for the classification of bergamot essential oils was evaluated by using multivariate statistical analysis. Two pattern recognition techniques, linear discriminant analysis and soft independent modeling of class analogy, were applied to MS data. The cross-validation procedure has shown excellent results in terms of the prediction ability because both models have correctly classified all samples for each category. [ABSTRACT FROM AUTHOR]

Paper cone spray ionization ( PCSI), an extractive ambient ionization method that is specialized for raw solid material analysis, was applied to chemical fingerprinting analysis of raw medicinal herbs. Experimental parameters of PCSI mass spectrometry ( MS) were first optimized against Salvia miltiorrhiza Bunge (danshen). Our results showed that simple alkyl alcohols, such as methanol and 2-propanol, generally worked well in both polarities and could generate representative chemical fingerprints instantly for a given herbal sample. In addition, in situ extraction from untreated herbal slices during PCSI MS was found to be enough to generate characteristic chemical signatures of a given medicinal herb. After optimization, representative fingerprints of various medicinal herbs, including Sophora flavescens (kushen) and Paeonia lactiflora Pall (shaoyao), were successfully obtained by PCSI MS. In addition, morphologically similar herbs, Cynanchum auriculatum and Cynanchum wilfordii, could be differentiated from each other by their chemical signatures by PCSI MS. [ABSTRACT FROM AUTHOR]

RATIONALE: The monitoring of chemical systems in dynamic equilibrium is not an easy task. This is due to the high rate at which the system returns to equilibrium after being perturbed, which hampers the possibility of following the aftereffects of the disturbance. In this context, it is necessary to use a fast analytical technique that requires no (or minimal) sample preparation, and which is capable of monitoring the species constituting the system in equilibrium. Paper spray ionization mass spectrometry (PS-MS), a recently introduced ambient ionization technique, has such characteristics and hence was chosen for monitoring a model system: the redox process of methylene blue. METHODS: The model system evaluated herein was composed of three cationic species of methylene blue (MB), which coexist in a dynamic redox system: (1) [MB]+ of m/z 284 (cationic MB); (2) [MB + H + e]+⋅ of m/z 285 (the protonated form of a transient species resulting from the reduction of [MB]+); (3) [MB + 2H + 2e]+ or [leuco-MB + H] + of m/z 286 (the protonated leuco form of MB). Aliquots of a MB solution were collected before and after the addition of a reducing agent (metallic zinc) and directly analyzed by PS-MS for identification of the predominant cationic species at different conditions. RESULTS: The mass spectra revealed that before the addition of the reducing agent the ion of m/z 284 (cationic MB) is the unique species. Upon the addition of the reducing agent and acid, however, the solution continuously undergo discoloration while reduced species derived directly from cationic MB (m/z 285 and 286) are detected in the mass spectra with increasing intensities. Fragmentation patterns obtained for each ionic species, i.e. [MB]+, [MB+H+e] +⋅ and [leuco-MB+H]+, shown to be consistent with the proposed structures. CONCLUSIONS: The PS-MS technique proved to be suitable for an in situ and 'near' real-time analysis of the dynamic equilibrium involving the redox of MB in aqueous medium. The data clearly demonstrated how the redox equilibrium shifts depending on the disturbance caused to the system. [ABSTRACT FROM AUTHOR]

Ambient ionization is achieved by spraying from a carbon nanotube (CNT)-impregnated paper surface under the influence of small voltages (≥3 V). Organic molecules give simple high-quality mass spectra without fragmentation in the positive or negative ion modes. Conventional field ionization is ruled out, and it appears that field emission of microdroplets occurs. Microscopic examination of the CNT paper confirms that the nanoscale features at the paper surface are responsible for the high electric fields. Raman spectra imply substantial current flows in the nanotubes. The performance of this analytical method was demonstrated for a range of volatile and nonvolatile compounds and a variety of matrices. [ABSTRACT FROM AUTHOR]

Paper spray ionization can be used to study organic reactions in solution under ambient conditions by utilizing the rate acceleration that occurs in reactions in small volumes of solution. In this novel approach to performing reactions, reagents are transferred onto a triangular paper surface by drop-casting and charged droplets of the reaction product mixture are released by field evaporation and examined online by mass spectrometry. The increase in the rate of product formation is attributed to solvent evaporation, which increases reagent concentrations, changes the pH, and enhances intermolecular interactions. As a proof of principle, the Katritzky reaction between a pyrylium salt and mono- or diamines, including substituted anilines, was investigated. The influence of electronic and steric effects was evaluated straightforwardly. The carbon chain length of α,ω-diamines was found to control the formation of mono- versus disubstituted products, thus reflecting the strong destabilizing coulombic effects in the shorter carbon-chain systems. Information on the mechanism was provided by the observation of 2 H-pyran intermediates and mixed pyridinium-2 H-pyran ions. The rates of product formation in the base-assisted Katritzky reaction increase linearly from 0.1 to 10 equivalents of triethylamine. The reactive paper spray technique, owing to its speed and information content, has potential pedagogical value and provides a tool to explore organic reactions and correlate experimental results with current mechanistic understanding. [ABSTRACT FROM AUTHOR]