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Investigates sequential electrospray analysis using sharp-tip channels fabricated on a plastic chip. Description of a plastic chip capable of performing sequential electrospray analysis; Introduction of high voltage into the sample solution; Observation of a stable Taylor cone at the exit of the channel.

Background: A mysterious skin rash (papular lesions) outbreak broke out for unknown reasons in Taiwan’s Pescadores Islands in mid‑autumn 2021, causing much anxiety in the population already nervous about the ongoing COVID‑19 epidemic. Objectives: We conducted a field survey for possible culprit agents. Methods: Skin samples were taken with rapid‑glue adhesives from the affected skin. Electron microscopy from the skin samples as well as caterpillar seta was performed. Additional neurotransmitter analysis by mass spectrometry (MS) was conducted on the skin samples. Results: A field survey found a large increase in caterpillars, Euproctis taiwana, in September 2021, the warmest September in recent years. Electron microscopy performed on superficial skin samples(3–6 cells thick) of affected and healthy skin (n = 5 and 3, respectively) and caterpillar setae revealed ultrastructural similarities between setae spurs (0.15–0.2 µm) and tiny pits (0.2 µm) on the affected skin as well as similar vegetative debris (0.75 µm) on both setae and affected skin. MS showed large increases in tyrosine, serine, and histamine, known mediators of arthropod insult. Conclusion: The co‑occurrence of E. taiwana population growth, excessive warming, and strong monsoon winds may lead to this unusual autumn outbreak in late September. The lifting of COVID‑19‑related travel restrictions against earlier that month probably exacerbated it. [ABSTRACT FROM AUTHOR]

A flame-induced atmospheric pressure chemical ionization (FAPCI) source, consisting of a miniflame, nebulizer, and heated tube, was developed to ionize analytes. The ionization was performed by reacting analytes with a charged species generated in a flame. A stainless steel needle deposited with saturated alkali chloride solution was introduced into the mini oxyacetylene flame to generate alkali ions, which were reacted with analytes (M) generated in a heated nebulizer. The alkali-adducted 18-crown-6 ether ions, including (M + Li)+, (M + Na)+, (M + K)+, (M + Rb)+, and (M + Cs)+, were successfully detected on the FAPCI mass spectra when the corresponding alkali chloride solutions were separately introduced to the flame. When an alkali chloride mixture was introduced, all alkali-adducted analyte ions were simultaneously detected. Their intensity order was as follows: (M + Cs)+ > (M + Rb)+ > (M + K)+ > (M + Na)+ > (M + Li)+, and this trend agreed with the lattice energies of alkali chlorides. Besides alkali ions, other transition metal ions such as Ni+, Cu+, and Ag+ were generated in a flame for analyte ionization. Other than metal ions, the reactive species generated in the fossil fuel flame could also be used to ionize analytes, which formed protonated analyte ions (M + H)+ in positive ion mode and deprotonated analyte ions (M - H)- in negative ion mode. [ABSTRACT FROM AUTHOR]

We aim to develop an efficient and non-invasive strategy for monitoring of drugs and their metabolites via human skin. Probe sampling was combined with thermal desorption-electrospray ionization tandem mass spectrometry (TDESI/ MS/MS) to characterize trace terbinafine, which was secreted on patient's skin after ingesting terbinafine tablets. The terbinafine ion signals were directly detected in the samples collected from different skin regions and the signals were monitored for 8 weeks. The detection and location of terbinafine via the skin suggest that the methods are useful in rapidly and noninvasively collecting the molecular information of the ingested drug on skin for pharmacokinetic studies. [ABSTRACT FROM AUTHOR]

The combination of laser-induced acoustic desorption and electrospray ionization mass spectrometry (LIAD/ESI/ MS) can be used to rapidly characterize chemical compounds separated on a thin layer chromatography (TLC) plate. We performed HAD analysis by irradiating the rear side of an aluminum-based TIC plate with a pulsed infrared (IR) laser. To efficiently generate and transfer acoustic and shock waves to ablate the analyte-containing TIC gels, a glass slide was attached to the rear of the TIC plate and the gap between the glass slide and the TIC plate was filled with a viscous solution (glycerol). Although the diameter of the laser spot created on the rear of the TLC plate was approximately 0.35 mm, the ablated areas on the front sides of the silica gel bed and the C,5 reverse- phase gel bed had diameters of approximately 1.3 and 3 mm, respectively. The ablated analyte molecules were ionized in an ESI plume and then detected by an ion trap mass analyzer. This TLC/LIAD/ESI/MS approach allowed the components in mixtures of dye standards, drug standards, and rosemary essential oil to be separated and rapidly characterized. [ABSTRACT FROM AUTHOR]

Despite the fact that carbamates and organophosphates cause acute poisoning via different mechanisms and require disparate management, they are indistinguishable by current clinical assays. Herein, direct immersion solid-phase microextraction (DI-SPME) plus thermal desorption-electrospray ionization tandem mass spectrometry (TD-ESI/MS/MS) was developed to discern them. Both pesticides spiked in human serum were extracted by SPME and analyzed by TD-ESI/MS/MS. This is a promising emergency care platform as rapid analyses could be done in tiny sample volumes with satisfactory recovery (89.46%e116.32%), precision (covariance <20%), sensitivity (LOD <0.1 mg/mL), turnaround time (<5 minutes), and linearity (R² = 0.9827e0.9992) within 0.1-100 mg/mL. [ABSTRACT FROM AUTHOR]

Examines the identification of biomolecules from high salt solutions by fused-droplet electrospray ionization mass spectrometry (FD-ESI-MS). Mechanism of ion formation in FD-ESI-MS; Production of protonated analyte during ion-molecular reactions; Reduction of electrospray stability by inorganic salts.

Thermal desorption-electrospray ionization tandem mass spectrometry (TD-ESI/MS/MS) was used to characterize the residual pesticides that were collected from the surface of a grape with metallic sampling probes. Fungicides, insecticides, and miticides were detected, where results were validated by simple solvent extraction followed by gas chromatography tandem mass spectrometry and liquid chromatography tandem mass spectrometry analyses. To explore the distribution of pesticide residues on grape surfaces, 149 locations of a grape surface were collected and followed by TD-ESI/MS/MS analysis. The molecular cartography was then generated from analysis of residual pesticides on the grape surface in 3D. [ABSTRACT FROM AUTHOR]

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 spectrom-etry (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. [ABSTRACT FROM AUTHOR]

Rapid characterization of thermally stable chemical compounds in solid or liquid states is achieved through thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS). A feature of this technique is that sampling, desorption, ionization, and mass spectrometric detection are four separate events with respect to time and location. A metal probe was used to sample analytes in their solid or liquid states. The probe was then inserted in a preheated oven to thermally desorb the analytes on the probe. The desorbed analytes were carried by a nitrogen gas stream into an ESI plume, where analyte ions were formed via interactions with charged solvent species generated in the ESI plume. The analyte ions were subsequently detected by a mass analyzer attached to the TD-ESI source. Quantification of acetaminophen in aqueous solutions using TD-ESI/MS was also performed in which a linear response for acetaminophen was obtained between 25 and 500 ppb (R2 = 0.9978). The standard deviation for a reproducibility test for ten liquid samples was 9.6%. Since sample preparation for TD-ESI/MS is unnecessary, a typical analysis can be completed in less than 10 s. Analytes such as the active ingredients in over-the-counter drugs were rapidly characterized regardless of the different physical properties of said drugs, which included liquid eye drops, viscous cold syrup solution, ointment cream, and a drug tablet. This approach was also used to detect trace chemical compounds in illicit drugs and explosives, in which samples were obtained from the surfaces of a cell phone, piece of luggage made from hard plastic, business card, and wooden desk. [ABSTRACT FROM AUTHOR]

Background: On April-May, 2011, two Taiwan chemical companies were found to have intentionally added phthalates, Di- (2-ethylhexyl) phthalate (DEHP) and/or Di-isononyl phthalate, as a substitute of emulsifier to many foodstuffs. This study aimed to investigate whether exposure to these foods altered endocrine functions in children aged ≤10 years and, if so, whether those changes could be reversed by stopping exposure. Methods: One Phthalates Clinic for Children was established in southern Taiwan between May 31 and June 17, 2011. All eligible children had their exposure information, blood and/or urine specimens collected. Endocrine functions were assessed in serum. The exposure groups were categorized into three (High, .500 ppm, Low, 1-500 ppm, and No, ,1 ppm of DEHP). After six months, some children were followed up for the selected endocrine hormones. Results: Sixty children were eligible in this study; all were Tanner stage 1 with no pubic hair. Compared to non-exposed group, both high and low exposure groups had significantly lower serum thyroid-stimulating hormone (TSH) levels (P = 0.001 and 0.024). At six months follow-up, serum triiodothyronine (T3) levels was significantly changed (P = 0.034) in high exposure group (n = 13). For serum estradiol (E2), the detectable rate ($8 pg/mL) decreased from 76.9% (10/13) to 30.8% (4/13) (P = 0.070). Conclusions: This study shows that serum TSH levels can be altered when children were exposed to high concentrations of phthalate-tainted foodstuffs. Serum E2 and T3 may be partially recovered after stopping exposure. [ABSTRACT FROM AUTHOR]

Interfacing thin layer chromatography (TLC) with ambient mass spectrometry (AMS) has been an important area of analytical chemistry because of its capability to rapidly separate and characterize the chemical compounds. In this study, we have developed a high-throughput TLC-AMS system using building blocks to deal, deliver, and collect the TLC plate through an electrospray-assisted laser desorption ionization (ELDI) source. This is the first demonstration of the use of building blocks to construct and test the TLC-MS interfacing system. With the advantages of being readily available, cheap, reusable, and extremely easy to modify without consuming any material or reagent, the use of building blocks to develop the TLC-AMS interface is undoubtedly a green methodology. The TLC plate delivery system consists of a storage box, plate dealing component, conveyer, light sensor, and plate collecting box. During a TLC-AMS analysis, the TLC plate was sent to the conveyer from a stack of TLC plates placed in the storage box. As the TLC plate passed through the ELDI source, the chemical compounds separated on the plate would be desorbed by laser desorption and subsequently postionized by electrospray ionization. The samples, including a mixture of synthetic dyes and extracts of pharmaceutical drugs, were analyzed to demonstrate the capability of this TLC-ELDI/MS system for high-throughput analysis. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG) is increasingly used in clinical and experimental medicine. Howsver, quantification of PEG and PEGylated small molecules remains laborious and unsatisfactory. In this report, we stably expressed a functional anti-PEG antibody on (he swface of BAIB 3T3 cells (3T3/αPEG cells) to develop a competitive enzyme-linked immunosorbent assay (EUSA) for PEG quantification. The ePEG cell-coated plate bound biotinylated PEGa (CH3PEG5K-biotin) and CH3-PEG5K1311 more effectively than did a traditional anti-PEG antibody-coated plate. Competitive binding between PEG (2,5, 10, or 20 kDa) and a known amount of CH3-PEG597biotin allowed construction of a repruducible competition cuave. The aPEG cellbased competition EUSA measured small molecules derivatized by PEG2K,PEG5K PEG10K PEG20K and PEGng at concentrations as low as 58.6, 14.6,3.7,3.7, and 14.6 ng/mL, respectively. Notably, the presence of senun orbovine serum albumin enhanced PEG measurement by the αPEG cell-based competition EUSA. Finally, we show here that the CIPEG cell-based competition EUSA accurately delineated the pharmacokinetics of PEG5K comparable to those determined by direct measurement of mdioaclbafy in blood after intravenous injection of CH3-PEG5K1311 into mice. This quantitative strateg,r may panvide a simple and sensitive method for quantifying PEG and PEGylated small molecules in vivo. [ABSTRACT FROM AUTHOR]

In the summer of 2008, serious illnesses and deaths of babies in China were linked to melamine-tainted powdered infant formula. Melamine contains several metabolites, such as ammeline, ammelide, and cyanuric acid, and has been used for the adulteration of foods or milk to increase their apparent protein content. It is assumed that melamine and its metabolites are absorbed in the gastrointestinal tract, and precipitate in the kidney to form crystals. A new tolerable daily intake of 0.2 mg kg−1 body weight was adapted by the World Health Organization in 2008. This paper reviews the variety of analytical methods that have been used for the analysis of melamine in food. The limit of detection of these various methods is 0.05–100 ppm. The maximum acceptable concentration in food has been set at 50 ppb by the US FDA. A fast and ultrasensitive procedure for screening, detection, and characterization of melamine and its derivative compounds needs to be established. Currently, mass-spectrometry technologies provide an alternative to derivatization for regulatory analysis of food. [ABSTRACT FROM AUTHOR]

Currently, no practical biomarker is available for the diagnosis of acute ischemic stroke. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has being applied extensively to analyze large biomolecules such as proteins. The technique is likely to be of remarkable value as indicators of systemic processes such as atherosclerosis and stroke. The aim of this study is to identify potential protein biomarkers for ischemic stroke diagnosis utilizing MALDITOF MS. Serum samples obtained from acute ischemic stroke patients (n = 47) and controls (n = 34) were analyzed by MALDI-TOF MS. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS), subtype by the Trial of Org 10172 in Acute Stroke Treatment (TOAST), functional outcome by the modified Rankin Scale (mRS) and infarct volume by the diffusion-weighted images. Risk factors and routine laboratory data of the stroke patients were registered prospectively. The peaks of hemoglobin (Hb) α-chain and β-chain were differentially expressed between stroke patients and controls ( p < 0.0001). Hb ions were detected in the samples collected from 33 (70.2 %) stroke patients and 5 (14.7 %) controls. The sensitivity is 70.2 % and the specificity is 85.3 %. Among stroke patients, there is no significant correlation ( p > 0.05) between Hb peaks and the NIHSS, TOAST, mRS, stroke risk factors, infarct volume, infarct location and laboratory data. Serum free Hb may serve as a novel potential biomarker for the diagnosis of acute ischemic stroke. The clinical value of this potential biomarker may be clarified by further studies quantifying serum free Hb levels. [ABSTRACT FROM AUTHOR]

We have coupled laser-induced acoustic desorption (LIAD) with electrospray ionization (ESI) mass spectrometry (LIAI)/ESI/MS) to characterize molecules in the solid state and in solution under ambient conditions. To perform an LIAD/ESI analysis, the sample droplet is deposited on the surface of a thin aluminum foil by a micropipette; the rear side of the foil with the sample spot is then irradiated with a pulse from a Nd:YAG IR laser. The resulting shockwave and heat cause the sample on the rear side to change from the condensed phase to the gas phase. The desorbed species then move upward to enter an ES! plume to react with charged solvent species (methanol. and water-related ions and droplets), forming singly or multiply charged analyte ions. A quadrupole/ time-of-flight (Q-TOF) mass analyzer attached to the LIAD/ESI source detects the analyte ions to obtain an ESI-like mass spectrum. Both small organic and large biological compounds (including amino acids, peptides, and proteins) were successfully ionized and detected by the LIAD/ESI/MS system. Although native and denatured myoglobin ions were both detected from a liquid sample solution, only the denatured myoglobin ions were detected from a dried sample. [ABSTRACT FROM AUTHOR]

Rapid characterization of synthetic polymers based on the differences in the appearance of the polar pyrolysate ions was achieved by electrospray-assisted pyrolysis ionization- mass spectrometry. The pyrolytical products produced by a commercial Curie point pyroprobe were conducted to the tip of a capillary, where charged methanol droplets were generated continuously by electro spray. Polar components in the pyrolysates, may react directly with the protonated methanol ions or fuse with the charged methanol droplets; electrospray ionization proceeds from the fused droplets to generate protoñated analyte ions. The mass spectra obtained through this approach were used to rapidly distinguish the polymer standards that differ in the nature of building units, degrees of polymerization, and copolymerization coefficients. [ABSTRACT FROM AUTHOR]

This study has developed two interfaces to connect smallsize thin-layer chromatography (TLC) with electrospray ionization mass spectrometry (ES-MS) for the continuous analysis of organic mixtures. The interfaces are (1) two bound optical fibers inserted into the C18-bonded particles at the exit of a small TLC channel and (2) a small commercial TLC strip with a sharpened tip. A reservoir continuously supplied a makeup solution to the tip of the TLC channel. The high voltage required for electrospray ionization was introduced into the makeup solution or mobile phase through a Pt wire, and electrospray was generated at the tip of the bonded optical fibers and at the sharp end of the TLC strip. Since small-size TLC channels were used, the elution time was short and less than 0.2 µL of the sample solution and 200 µL of the eluting solvent were required. Organic mixtures were separated successfully and detected on-line using the TLC/ES-MS techniques. [ABSTRACT FROM AUTHOR]