Rapid quantification of acetaminophen in plasma using solid-phase microextraction coupled with thermal desorption electrospray ionization mass spectrometry

RATIONALE

Solid-phase microextraction coupled with thermal desorption electrospray ionization tandem mass spectrometry (SPME-TD-ESI-MS/MS) is proposed as a novel method for the rapid quantification of acetaminophen in plasma samples from a pharmacokinetics (PK) study.

METHODS

Traces of acetaminophen were concentrated on commercial fused-silica fibers coated with a polar polyacrylate (PA) polymer using direct immersion SPME. No agitation, heating, addition of salt, or adjustment of the pH of the sample solution was applied during the extraction. Any acetaminophen absorbed on the SPME fibers was subsequently desorbed and detected by TD-ESI-MS/MS.

RESULTS

Parameters of the absorption, sensitivity, reproducibility, and linearity for the SPME-TD-ESI-MS/MS method were evaluated. The time required to complete a TD-ESI-MS/MS analysis was less than 30 seconds. Matrix-matching calibration was performed to calculate the concentration of acetaminophen in the sample. A linear calibration curve with a concentration range of 100-10,000 ng/mL was constructed to calculate the quantity of acetaminophen. The SPME-TD-ESI-MS quantification results for acetaminophen in plasma were in good agreement with those obtained by the conventional LC/MS/MS method.

CONCLUSIONS

With the proposed method, a 10-min SPME time was enough to achieve the lower limit of quantitation (i.e. 100 ng/mL) and for a complete PK profiling of acetaminophen. A shorter extraction time could be achieved by applying agitation, heating, adding salt, or adjusting the pH of the sample solution to enhance analyte absorption efficiency. The time required to detect acetaminophen on the SPME fiber was less than 30 s, allowing the rapid quantification of acetaminophen in plasma with good accuracy.

Identification and characterization of unknown degradation impurities in beclomethasone dipropionate cream formulation using HPLC, ESI-MS and NMR

The present study focuses on identifying the degradation profile and pathways of unknown impurities from beclomethasone dipropionate (BDP) topical cream formulation reported under accelerated stability conditions. Six degradation impurities were observed during the accelerated stability testing of BDP topical cream formulation, and these thermally labile degradation impurities were primarily identified using a simple, effective and mass compatible isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection method. The degradation impurities found in this sample were of very low concentration levels, thus the concentration of these impurities in the sample was enriched by mimicking the thermal degradation conditions to structurally elucidate the unknown impurities. These BDP thermal degradation impurities were isolated using preparative liquid chromatography and followed by pre-concentration using rota-vapour. Further, the collected thermal degradation impurities were characterized using ESI-MS, and the major impurity was identified using ¹H and C¹³ NMR spectroscopy, and DEPT technique. Plausible degradation pathway and mechanism of each impurity from BDP has been proposed based on the obtained mass and NMR spectral data. Thus, the present method is simple and suitable to be applied towards BDP assay in various formulations, and also to investigate the thermal stability and degradation kinetics of the final drug product.

Direct and rapid characterization of illicit drugs in adulterated samples using thermal desorption electrospray ionization mass spectrometry

Foods and drinks have been adulterated with illicit drugs to facilitate criminal activities. Unfortunately, conventional analytical methods are incapable of rapidly characterizing these drugs in samples, as serious interferences from sample matrices must be removed through tedious and time-consuming pretreatment. Ambient ionization mass spectrometry (AMS) generally does not require sample pretreatment and is thus a suitable tool for directly and rapidly detecting illicit drugs in samples in different physical states. In this study, thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS), an AMS technique, was utilized to efficiently characterize illicit drugs spiked in samples including drinks, powders, and jelly candies. To perform sensitive analysis, the mass analyzer was operated in multiple reaction monitoring mode to monitor the molecular and fragment ions of the target analytes. The time required to complete a typical TD-ESI/MS analysis was less than 30 s. The limits of detection (LODs) for illicit drugs were found to be 100 ppb in drinks, 100–1000 ppb in instant powders, and 1.3–6.5 ng/mm² on stamp surfaces. FM2 and nitrazepam laced in the inner layer of a jelly candy were detected by TD-ESI/MS, showcasing the advantage of the technique for direct and rapid analysis as opposed to conventional methods.

Ambient mass spectrometry for rapid diagnosis of psychoactive drugs overdose in an unstable patient

A 25-year-old man suffered from consciousness change was sent to our emergency department by friends who reported that they were not sure what had happened to him. Physical examination revealed bilateral pupils dilatation, lethargy, slurred speech, and ataxia. Computer-aided tomographic scan of the brain revealed no definite evidence of intracranial lesions. Routine laboratory tests revealed total physiological turmoil. Despite immediate commencement of aggressive treatment, the patient's condition deteriorated long before the traditional drug screen provided an answer for the identities of the multiple drugs overdose. It ended up with the need for cardiopulmonary resuscitation, but in vain. At the end of the tragic event, under the suggestion of a colleague, a portion of the patient's urine specimen was sent to our university esoteric laboratory for rapid analysis by means of a newly-developed thermal desorption-electrospray ionization-mass spectrometry. Ketamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyamphetamine were identified in the urine sample within 30s. Conventional toxicological testing techniques like gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry are currently used for identifying abused drugs. One concern is their time-consuming sample pretreatment which leads to relatively low efficiency in terms of turnaround time for revealing the identity of the consumed drugs particularly when the patients are severely overdosed. We learned a lesson from this case that a more efficient toxicological identification technique is essential to expedite the process of emergency care when the patients are so heavily overdosed that they are under critical life-threatening conditions.

Urinary Concentrations of Triclosan, Benzophenone-3, and Bisphenol A in Taiwanese Children and Adolescents

The purpose of this study was to determine the levels of urinary triclosan (TCS), benzophenone-3 (BP-3), and bisphenol A (BPA) in 52 children and 71 adolescents. The effects of age and sex on the levels of urinary TCS, BP-3, and BPA were explored, respectively. Results demonstrated the overall detection rates of urinary TCS, BP-3, and BPA were 18.7%, 8.1%, and 49.6%, respectively. The females had higher TCS concentrations than males (p = 0.051). The detection rate of urinary BP-3 in females (12.3%) was higher than that in males (0%) (p = 0.015). Moreover, the detection rate of urinary BP-3 in adolescents (14.1%) was higher than that in children (0%) (p = 0.005). For children, no urinary BP-3 was found. There were no differences in detection rates and concentrations of urinary TCS, BP-3, and BPA between males and females, respectively. For adolescents, urinary BP-3 was only found in the females. Urinary TCS levels in females were higher than those in males (p = 0.047). The present study showed that urinary TCS concentrations in females were significantly higher than those in males, respectively. In addition, BP-3 was only detected in urine samples of female adolescents. Sex and age were the important factors influencing urinary TCS and BP-3 concentrations.

Rapid and simple analysis of disease-associated biomarkers of Taiwanese patients with schizophrenia using matrix-assisted laser desorption ionization mass spectrometry

BACKGROUND

Matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS) is an extremely sensitive analytical tool for characterizing biological compounds in bio samples. In this study, we applied MALDI-TOF MS to assess potential protein biomarkers in the peripheral blood mononuclear cells (PBMCs) of patients with schizophrenia in the acute phase, recovery phase and healthy controls in Taiwan.

METHODS

We recruited 40 participants, including 20 pairs of patients diagnosed with schizophrenia in the acute phase, after four-week treatment with drug in the recovery phase, and 20 healthy controls. The schizophrenic patients were diagnosed using Structured Clinical Interview for DSM-IV Axis I Disorders (SCID), and severity was assessed by a positive and negative symptom scale at baseline and at endpoint following four-week treatment with drug. The patients' PBMCs biomarkers were rapidly measured using a technique that combines MALDI-TOF MS and principle component analysis. A receiver operating characteristic curve was created for the evaluated biomarker.

RESULTS

Significant differences in α-defensins 1-3 were found between the patients in acute phase with schizophrenia and the healthy controls, but not between the schizophrenic patients in recovery phase and healthy controls or between the schizophrenic patients in acute phase and in recovery phase.

CONCLUSIONS

α-Defensins can be biomarkers of Taiwanese patients with schizophrenia, thus supporting the hypothesis that the inflammatory response and immunity system is correlated with the pathophysiology of schizophrenia. Moreover, the result also implies that α-defensins may be related in schizophrenia-associated disease not in efficacy of drug-treatment.

Flame Atmospheric Pressure Chemical Ionization Coupled with Negative Electrospray Ionization Mass Spectrometry for Ion Molecule Reactions

Flame atmospheric pressure chemical ionization (FAPCI) combined with negative electrospray ionization (ESI) mass spectrometry was developed to detect the ion/molecule reactions (IMRs) products between nitric acid (HNO₃) and negatively charged amino acid, angiotensin I (AI) and angiotensin II (AII), and insulin ions. Nitrate and HNO₃-nitrate ions were detected in the oxyacetylene flame, suggesting that a large quantity of nitric acid (HNO₃) was produced in the flame. The HNO₃ and negatively charged analyte ions produced by a negative ESI source were delivered into each arm of a Y-shaped stainless steel tube where they merged and reacted. The products were subsequently characterized with an ion trap mass analyzer attached to the exit of the Y-tube. HNO₃ showed the strongest affinity to histidine and formed (M_histidine-H+HNO₃)^- complex ions, whereas some amino acids did not react with HNO₃ at all. Reactions between HNO₃ and histidine residues in AI and AII resulted in the formation of dominant [M_AI-H+(HNO₃)]^- and [M_AII-H+(HNO₃)]^- ions. Results from analyses of AAs and insulin indicated that HNO₃ could not only react with basic amino acid residues, but also with disulfide bonds to form [M-3H+(HNO₃)_n]^3- complex ions. This approach is useful for obtaining information about the number of basic amino acid residues and disulfide bonds in peptides and proteins. Graphical Abstract ᅟ.

Rapid characterization of trace aflatoxin B1 in groundnuts, wheat and maize by dispersive liquid-liquid microextraction followed by direct electrospray probe tandem mass spectrometry

RATIONALE

Aflatoxins are poisonous and cancer-related chemical compounds commonly found in crops and plants. Aflatoxin B₁ is the most toxic compound among aflatoxins and has been classified as group 1 carcinogenic to humans, especially in liver cancer. Herein, an ambient mass spectrometric method was developed for rapid characterization of trace aflatoxin B₁ in peanuts.

METHODS

Direct electrospray probe tandem mass spectrometry (DEP-MS/MS) was used to detect aflatoxin B₁ in peanuts. To avoid the matrix effect, the aflatoxin B₁ in the samples was extracted and concentrated by dispersive liquid-liquid microextraction. The mass spectrometer was operated in the positive ion mode to monitor the intact molecular ion (m/z 313, MH⁺ ) and product ion (m/z 241) of aflatoxin B₁ using multiple reaction monitoring.

RESULTS

Since no clean-up procedure of the sample was required, the sampling step and the subsequent mass spectrometric detection of the aflatoxin B₁ was completed in less than 5 min. The limit of detection of aflatoxin B₁ is at the sub-ppb level. The results obtained by DEP-MS/MS were also validated by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Recovery of aflatoxin B₁ in the sample was evaluated by analyzing spiked aflatoxin B₁ with LC/MS/MS to be 85% and DEP-MS/MS to be 84%.

CONCLUSIONS

DEP-MS/MS combined with a simple dispersive liquid-liquid microextraction procedure was successfully used for the quantitative analysis of AFB₁ in nut samples. Due to its high efficiency, it is promising in providing important toxicological information for food safety in the real world. Copyright © 2017 John Wiley & Sons, Ltd.

Rapid Identification of Psychoactive Drugs in Drained Gastric Lavage Fluid and Whole Blood Specimens of Drug Overdose Patients Using Ambient Mass Spectrometry

Psychoactive drug overdoses are life-threatening and require prompt and proper treatment in the emergency room to minimize morbidity and mortality. Prompt identification of the ingested psychoactive drugs is challenging, since witness recall is unreliable and patients' symptoms do not necessarily explain their loss of consciousness. Gas and liquid chromatography mass spectrometric analyses have been the traditionally employed methods to detect and identify abused substances; however, these techniques are time-consuming and labor-intensive. In this study, thermal desorption electrospray ionization mass spectrometry, an ambient mass spectrometric technique, was applied to rapidly characterize flunitrazepam, lysergic acid diethylamide, and 3,4-methylenedioxy-methamphetamine in drained gastric lavage fluid, and ketamine, cocaine, amphetamine and norketamine in whole blood samples. No pretreatment of the gastric lavage fluid specimens was required and the entire analytical process took less than 30 s per specimen. Liquid-liquid extraction, followed by centrifugation, was performed on the whole blood samples. The corresponding compounds were identified through matching the obtained mass spectrometric data with those provided by commercial databases. The limits-of-detection of the tested drugs in both drained gastric lavage fluid and whole blood samples are at sub ppm levels. This is sensitive enough for emergency medical application, since the quantities of medications ingested by overdosed abusers are much higher than the amounts that were tested.

Removal of Diethylhexyl Phthalate from Hands by Handwashing: Evidence from Experimental N-of-1 and Crossover Designs

Phthalate exposure through skin is often neglected due to the small quantity and limited dermal absorption rate. However, free phthalate can be ingested by hand-to-mouth action or by contact with food. To evaluate the effectiveness in removing phthalate exposure on hand, we compare here the removal efficiency of di-(2-ethylhexyl)phthalate (DEHP) on hands by handwashing with soap-and-water versus water-only. In two three-day N-of-1 trials, residual DEHP was measured in a single female adult who washed exposed hands with soap-and-water or water-only. Subsequently, a crossover study was performed by randomly assigning another 28 subjects equally to wash with soap-and-water or with water-only, and then each one received the other treatment 24 hrs later. In the N-of-1 trials, mean DEHP removal rates range from 95.9% (SD = 0.1%) to 97.0% (SD = 2.5%) for soap-and-water handwashes, and 1.8% (SD = 0.1%) to 7.0% (SD = 0.3%) (n = 3) for water-only. In the crossover study, mean removal rate was 94.6% (SD = 6.5%) for handwashing with soap-and-water (n = 28) and 8.7% (SD = 5.7%) for water-only (n = 28). We concluded that handwashing with soap-and-water removes 80% more DEHP than handwashing with water alone, and may be a cost-effective way of removing other endocrine disruptors from hands.

Desorption Flame-Induced Atmospheric Pressure Chemical Ionization Mass Spectrometry for Rapid Real-World Sample Analysis

Flame-induced atmospheric pressure chemical ionization (FAPCI) is a solvent and high voltage-free APCI technique. It uses a flame to produce charged species that reacts with analytes for ionization, and generates intact molecular ions from organic compounds with minimal fragmentation. In this study, desorption FAPCI/MS was developed to rapidly characterize thermally stable organic compounds in liquid, cream, and solid states. Liquid samples were introduced into the ion source through a heated nebulizer, and the analytes formed in the heated nebulizer reacted with charged species in the source. For cream and solid sample analysis, the samples were positioned near the flame of the FAPCI source for thermal desorption and ionization. This approach provided a useful method to directly characterize samples with minimal pretreatment. Standards and real-world samples, such as drug tablets, ointment, and toy were analyzed to demonstrate the capability of desorption FAPCI/MS for rapid organic compound analysis.

Rapid detection of alteration of serum IgG in patients with schizophrenia after risperidone treatment by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry

RATIONALE

The aim of the study was to use a technique that combines acid hydrolysis and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS) in order to detect the serum biomarkers of patients diagnosed with schizophrenia both before and after four-week antipsychotic treatment with risperidone.

METHODS

During this study's two-year period, inpatients were diagnosed with schizophrenia using the Structured Clinical Interview for DSM-IV Axis I Disorders. Severity was then evaluated using the Positive and Negative Syndrome Scale both at baseline and at endpoint following four-week treatment with risperidone. The patients' serum biomarkers were quickly measured using acid hydrolysis and MALDI-TOF MS. The resulting peptides were then analyzed using MALDI-TOF MS. We constructed a receiver operating characteristic (ROC) curve for the evaluated biomarkers.

RESULTS

We recruited 20 pairs of participants for this study. The experimental group was treated with serum protein with HCl for 10 minutes to effectively hydrolyze abundant proteins. The target peptide, the immunoglobulin gamma chain (IgG), was then rapidly detected using this manner. A significant difference was found in the IgG levels of patients with schizophrenia before and after antipsychotic treatment. We constructed a ROC curve based on the IgG, and the area under said curve was 0.969. In comparison to conventional detection protocols, this method takes only minutes to complete and is also less costly.

CONCLUSIONS

This study found that applying acid hydrolysis with MALDI-TOF MS technology could rapidly differentiate serum IgG levels in patients with schizophrenia before and after being treated with risperidone. This IgG difference may enhance the understanding of mechanism of antipsychotic treatment of schizophrenia. Copyright © 2016 John Wiley & Sons, Ltd.

Rapid point-of-care identification of oral medications in gastric lavage content by ambient mass spectrometry in the emergency room

RATIONALE

Acute poisoning should be handled with high efficiency in order to minimize morbidity and mortality in the emergency room. Unfortunately, history-taking and physical examination are not always reliable. Mis-swallowing of oral medications is common in the pediatric group. This study aimed at developing a rapid point-of-care ambient mass spectrometric method for the early identification of ingested oral medications in gastric lavage content.

METHODS

Four different types of oral medications that are most commonly mis-swallowed by children were diluted to different concentrations. Each of these chemical solutions was mixed with human gastric lavage content. A direct metallic sampling probe was dipped into the solution. It was then inserted promptly into the thermal desorption electrospray ionization source to carry out ionization and subsequent mass spectrometric analysis of the medications. The corresponding compounds were identified through matching of the obtained mass spectrometric data with those provided by well-established databases.

RESULTS

Since no pretreatment of the specimen was required, the sampling step, and the subsequent thermal desorption electrospray ionization and mass spectrometric detection of the medications were completed within 30 s. Mass spectra were obtained for four different kinds of oral medication. The limit-of-detection of the four tested oral medications in gastric lavage content is at sub-ppm level, which is sensitive enough for emergency medicine applications since the quantities of medications ingested by pediatric patients are usually much higher.

CONCLUSIONS

Thermal desorption electrospray ionization mass spectrometry, with informational support provided by an online mass spectral database, allows for early point-of-care identification of mis-swallowed oral medications in the evacuated gastric lavage contents obtained from gastric lavage of patients in the emergency room, and it is promising in providing important toxicological information to ensure the appropriateness of the subsequent medical management. Copyright © 2016 John Wiley & Sons, Ltd.

Flame-induced atmospheric pressure chemical ionization mass spectrometry

RATIONALE

Charged species such as formylium (CHO(+) ), hydronium (H3 O(+) ), and water clusters [H3 O(+) (H2 O)n ] are commonly found in flames. These highly reactive species can react with analytes via ion-molecule reactions (IMRs) to form analyte ions. A new mass spectrometric technique, named flame-induced atmospheric pressure chemical ionization mass spectrometry (FAPCI-MS), was developed to characterize organic compounds via these mechanisms.

METHODS

A commercial corona-discharge atmospheric pressure chemical ionization (APCI) source was modified by replacing the corona needle with a flame to make a FAPCI source. Liquid samples were vaporized in a heated tube and delivered to the IMRs region by nitrogen to react with the charged species generated by a flame. Analytes on surfaces were directly desorbed and ionized by a flame using the technique called desorption-FAPCI-MS (DFAPCI-MS).

RESULTS

Intact molecular ions of various chemical and biological compounds were successfully characterized by FAPCI-MS. The FAPCI mass spectra are nearly identical to those obtained by traditional APCI-MS. The limit of detection (LOD) of reserpine by FAPCI-MS was 50 μg L(-1) with a linear calibration curve (R(2) = 0.9947) from 100 μg L(-1) to 10 mg L(-1) . The LOD for ketamine by DFAPCI-MS was estimated to be less than 0.1 ng.

CONCLUSIONS

In FAPCI, analytes are not incinerated but vaporized and introduced into the ion source to react with the reactive charged species generated by a flame. The features of the FAPCI source include: configuration is very simple, operation is easy, high voltage or inert gas is unnecessary, and the source is maintenance free. Various combustible gases, solvents and solids are useful flame fuels for FAPCI. Copyright © 2016 John Wiley & Sons, Ltd.

Rapid identification of pesticides in human oral fluid for emergency management by thermal desorption electrospray ionization/mass spectrometry

Self-poisoning with pesticides accounts for approximately one-third of all suicides worldwide. To expedite rescue in the emergency department, it is essential to develop a point-of-care analytical method for rapid identification of ingested pesticides. In this study, five of the most common pesticides ingested by self-poisoning patients in Taiwan were analyzed from oral fluid samples. Pesticide-oral fluid mixtures were applied on a cotton swab and then transferred into methanol. A metallic probe was used to sample the methanol solution for subsequent thermal desorption-electrospray ionization mass spectrometry analysis. Altogether, pesticide sampling, transfer, desorption, ionization, and detection took less than 1 min. The reproducibility of this method (n = 6) was shown in the observed low-relative standard deviation (<7%) in the detection of pesticide in oral fluid. The detection limits of the pesticides in oral fluid obtained from four human subjects by thermal desorption-electrospray ionization mass spectrometry were between 1-10 ppb with relative standard deviation 10.7%. Moreover, in this study, linear responses of five pesticides in oral fluid with concentrations between 1 ppb-1 ppm (R2 between 0.9938 and 0.9988) were observed. As the whole analytical process is extremely short, this technique allows for early non-invasive point-of-care identification of pesticides in the oral fluid of self-poisoning patients in the emergency room, providing important toxicological information for decision-making during critical resuscitation.

Depth profiling of inks in authentic and counterfeit banknotes by electrospray laser desorption ionization/mass spectrometry

Electrospray laser desorption ionization is an ambient ionization technique that generates neutrals via laser desorption and ionizes those neutrals in an electrospray plume and was utilized to characterize inks in different layers of copy paper and banknotes of various currencies. Depth profiling of inks was performed on overlapping color bands on copy paper by repeatedly scanning the line with a pulsed laser beam operated at a fixed energy. The molecules in the ink on a banknote were desorbed by irradiating the banknote surface with a laser beam operated at different energies, with results indicating that different ions were detected at different depths. The analysis of authentic $US100, $100 RMB and $1000 NTD banknotes indicated that ions detected in 'color-shifting' and 'typography' regions were significantly different. Additionally, the abundances of some ions dramatically changed with the depth of the aforementioned regions. This approach was used to distinguish authentic $1000 NTD banknotes from counterfeits. Copyright © 2015 John Wiley & Sons, Ltd.

Letter: Supermetallization of peptides and proteins with tetravalent metal Th(IV)

Supermetallization is the recently observed phenomenon of the formation of complex ions of peptide-metal in the gas phase when the peptide accepts an unexpectedly large number of metal atoms. It has been found that supermetallization takes place during electrospray ionization when charged droplets are evaporating at relatively high temperature (ca 400°C). In the present paper, we demonstrate supermetallized complexes of small protein ubiquitin and two peptides with Th(IV). We have observed complexes of ubiquitin with up to five thorium atoms, and attaching each Th(IV) requires the removal of four hydrogen atoms. To our knowledge, this is the first demonstration of gas-phase complexes of peptides and proteins with tetravalent metal atoms..