Corona Discharge Ionization Ion Mobility Spectrometry Research Articles

Semi-automated filter micro-solid phase extraction based on urea-formaldehyde microsphere followed by corona discharge-ion mobility spectrometry for simultaneous detection of fentanyl and nor-fentanyl in urine

In this work, semi-automated filter micro-solid phase extraction (SA-FμSPE) packed by urea–formaldehyde (UF) microspheres coupled with corona discharge ionization-ion mobility spectrometry (CD-IMS) was developed for the extraction and determination of fentanyl and nor-fentanyl in urine samples. UF microspheres, synthesized by aqueous polymerization, can be used to achieve effective extraction of analytes through multiple adsorption interactions such as hydrophobic, dipole–dipole and hydrogen bonding interactions. UF microspheres dispersed in methanol were packed in the filter by syringe, and the extraction process was performed by a portable automatic filter extraction device. The parameters affecting extraction efficiency (i.e., extraction time, the flow rate of extraction, pH value, amount of sorbent, ionic strength, cycle times of desorption, and type of eluent) were investigated. Then, the eluate containing fentanyl and nor-fentanyl was simultaneously analyzed by CD-IMS in positive mode. Under the optimal extraction conditions, the detection limits for the target compounds were 5.00 ng mL−1 and 8.00 ng mL−1, respectively. The spiked recoveries were in the range of 81.97 % −112.37 % by testing the real samples and validated by UHPLC-MS. Thus, the satisfactory results reveal that SA-FμSPE coupled with CD-IMS has great potential for on-site extraction and detection of fentanyl and nor-fentanyl in urine samples.

Novel UiO‐66‐NH2/Gly/GO Nanocomposite Adsorbent for Ultra‐trace Analyzing of Chlorpyrifos Pesticide by Ion Mobility Spectrometry

AbstractThis paper seeks to produce UiO‐66‐NH2/Gly/GO nanocomposite, which is solvothermally synthesised by the “prefunctionalisation” approach using 2‐aminoterephthalic acid as an organic linker in a Teflon lined autoclave and its linking to a graphene surface by glycine and finally characterized by methods such as FTIR spectrometer, Powder X‐ray diffraction (XRD), energy dispersive X‐ray analysis (EDAX), thermal stability measurement (TGA), transmission electron microscope (TEM), scanning electron microscope (SEM) and the Brunauer‐Emmet‐Teller (BET). UiO‐66‐NH2/Gly/GO nanocomposite has been exploited as an adsorbent in solid phase microextraction (SPME) method and also the pesticide chlorpyrifos as an organophosphorous pesticide is selected for the model compound. As for a determination system, Corona discharge ionization‐ion mobility spectrometry (CD‐IMS) has been employed. The nanocomposite capability in extracting the target analyte before and after the coating of the GO has been experimentally investigated. The IMS sensitivity has been strikingly increased in the course of using the GO as the nanocomposite coating. In order to increase the extraction efficiency and preconcentration of the analyte, both extraction temperature and time are scrutinized. All through this method, analysis factors are achieved as follows: linear dynamic range (LDR); 0.5‐20.0 μg L−1, correlation coefficient (R2); 0.9992, the limit of quantification (LOQ); 0.5 μg L−1, and limit of detection (LOD); 0.15 μg L−1. On the whole, the proposed approach seems to be regarded as a successful method for analyzing the organophosphouros pesticide.

Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour.

Fabricating suitable adsorbents with low-cost and high efficiency extraction for measurement of very small amounts of agricultural pesticides in food and water is playing a vital key role in personal and environmental health. Here, a new composite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios. Several techniques such as FE-SEM, BET, XRD, and TGA have been used to confirm the structural characterization of the obtained materials. The obtained ZIF-67@MgAl2O4 was utilized as an adsorbent in the solid phase microextraction technique to extract and preconcentrate the herbicide molinate (as an analyte) in aqueous solution. Corona discharge ionization-ion mobility spectrometry (CD-IMS) was applied for quantification of the analyte molecules. Extraction temperature, extraction time, stirring rate, and sample pH as the main parameters that affected the extraction proficiency were chosen and considered. Under optimal conditions, the linear dynamic range (LDR) of the various concentrations of the molinate and correlation coefficient were 10.0–100.0 μg L−1 and 0.9961, respectively. The limit of quantification (LOQ) and method detection limit (MDL) were 10.0 μg L−1 and 3.0 μg L−1, respectively. The relative standard deviation (RSD) of the ZIF-67@MgAl2O4 for extracting the molinate molecules (molinate concentration; 50 μg L−1) was calculated to be 4% and the enrichment factor (EF) was ∼5.

Covalent triazine-based framework-grafted functionalized fibrous silica sphere as a solid-phase microextraction coating for simultaneous determination of fenthion and chlorpyrifos by ion mobility spectrometry.

A novel covalent triazine-based framework (CTF)-grafted phenyl-functionalized fibrous silica nanosphere, KCC-1 (named as RS-2) was synthesized via a simple and effective Friedel-Crafts approach. The microporous CTF with fluorene backbone was coupled and grown uniformly on the surface of phenyl-functionalized KCC-1 to prepare a hybrid extended porous framework. The prepared materialswere characterized, and FE-SEM and TEM images revealed a flower-like structure for RS-2. The synthesized RS-2 showed excellent thermal stability, so the weight loss was about 30% at 800°C. RS-2 was applied as a new coating in the solid-phase microextraction procedure to extract chlorpyrifos and fenthion pesticides fromwater, wastewater, and fruit samples, before determining by corona discharge-ion mobility spectrometry. Some experimental factors affecting the extraction yield of the analytes, including ionic strength, stirring rate, sample pH, extraction temperature, and extraction time, were investigated. Under optimum conditions, the linear dynamic ranges were 0.1-10μgL-1 and 1.0-70μgL-1, and the limits of detection were 0.05 and 0.55μgL-1 for chlorpyrifos and fenthion, respectively. The proposed method showed recovery values in the range 86-117% with a precision of 3.0-7.1% for real samples. Covalent triazine-based framework (CTF)-grafted phenyl-functionalized fibrous silica nanosphere (named as RS-2) was synthesized. RS-2 was applied as a sorbent for solid-phase microextraction (SPME) of chlorpyrifos and fenthion from fruit and water samples followed by corona discharge ionization ion mobility spectrometry (CD-IMS).

Organic solvent supported silica aerogel thin film microextraction: An efficient sample preparation method for ion mobility spectrometry

A hyphenated method consisting of liquid-phase microextraction and solid-phase microextraction was presented as a sample preparation method. To that end, silica aerogel thin film microextraction prepared by electrospinning procedure was coated by organic solvent (tetrachloromethane) and used for extraction of molinate herbicide as a test compound. Corona discharge ionization-ion mobility spectrometry was applied as the detection system. Some parameters affected the extraction efficiency were evaluated and optimized with the response surface method. Under optimum conditions, the linear dynamic range was obtained 0.20–7.0 µg L−1, and the method detection limit and limit of quantification were obtained 0.075 and 0.20 µg L−1, respectively. The relative standard deviations of intra- and inter-day were calculated 4% and 7%, respectively, and the enrichment factor for the spiked sample (2 µg L−1) was obtained 600. Different real samples, including tomato, apple, carrot, agricultural wastewater, well water, river water, and drinking water samples were used for investigating the capability of the proposed method. The relative recovery values for these samples were obtained in the range of 90–108%. The satisfactory results disclosed that the organic solvent- thin-film microextraction could be utilized as an efficient sample preparation method for analyzing molinate in complex matrices.

Ultrasonic Piezoelectric Nebulization of Propoxur for the Determination by Corona Discharge Ionization Ion Mobility Spectrometry.

Propoxur insecticide as a thermally unstable compound (decomposed at its boiling point) could not be analyzed by traditional sample introduction systems based on the thermal desorption. In this study, an ultrasonic piezoelectric nebulizing injection port was applied for evaporating this compound prior to its determination by corona discharge ionization ion mobility spectrometry (CD-IMS). The target analyte was extracted from different water samples by using the extraction method of dispersive liquid-liquid microextraction. Methanol and trichloromethane were utilized as the disperser and extraction solvents, respectively. The effective variables included the volume of the disperser and the extraction solvents, the pH, and the centrifugation time were studied by a Fractional Factorial Design to identify the important parameter(s) and their interaction. To that end, a Central Composite Design was performed to achieve optimum levels of each effective parameter. The results showed that the optimum conditions were 78 μL of the extraction solvent, and 1.2 mL for the disperser solvent; centrifugation time was 1 min at 1010g, and finally pH 7. A detection limit of 2.1 μg L-1, a linear range of 2.5 - 80 μg L-1, and a relative standard deviation of 7% were obtained. Different water samples were analyzed by the proposed technique, and the propoxur amounts were successfully determined. The obtained results revealed satisfactory relative recovery values of between 91 and 105%.

On-site rapid screening of benzodiazepines in dietary supplements using pipette-tip micro-solid phase extraction coupled to ion mobility spectrometry

In this study, a reliable and novel coupling of pipette-tip micro-solid phase extraction (PT-µSPE) with corona discharge ionization-ion mobility spectrometry (CD-IMS) was developed for on-site fast detection of benzodiazepines (BZDs) in dietary supplements. The poly (styrene-co-divinylbenzene) (St-co-DVB) monoliths fabricated in pipette-tips through an in-situ polycondensation reaction. The extraction procedure of PT-µSPE for aqueous sample was performed for an appropriate number of aspirating/dispensing cycles by using a manual micropipettor. Then analytes retained in the polymeric monoliths were eluted with elution solvents by repeating the aspirating/dispensing cycles, and the eluates were analyzed by CD-IMS. In order to find the best extraction conditions, several parameters such as the number of aspirating/dispensing cycles for extraction and desorption, pH, elution solvent, amount of polymer and ionic strength were investigated. Under the optimal conditions, the LOD of this method was in the range of 5–15 ng mL−1. The spiked recovery values in real sample were obtained by PT-µSPE-IMS in the range of 84.2–112.1% and validated by ultraperformance liquid chromatography tandem mass spectrometry (UPLC–MS/MS). PT-µSPE as an on-site sampling method can be suitably combined to IMS which has great potential to achieve high throughput detection by using a multichannel micropipette. The satisfactory analytical results reveal that the developed method can be effectively applied for on-site screening BZDs in health products.

Towards metals analysis using corona discharge ionization ion mobility spectrometry

For the first time, the capability of corona discharge ionization ion mobility spectrometry (CD-IMS) in the determination of metal complex was evaluated. The extreme simplicity of dispersive liquid–liquid microextraction (DLLME) coupled to the high sensitivity of CD-IMS measurement could make this combination really useful for simple, rapid, and sensitive determination of metals in different samples. In this regard, mercury, as a model metal, was complexed with diethyldithiocarbamate (DEDTC), and then extracted into the carbon tetrachloride using DLLME. Some parameters affecting the extraction efficiency, including the type and volume of the extraction solvent, the type and volume of the disperser solvent, the concentration of the chelating agent, salt addition and, pH were exhaustively investigated. Under the optimized condition, the enrichment factor was obtained to be 142. The linear range of 0.035–10.0 μg mL−1 with r2 = 0.997 and the detection limit of 0.010 μg mL−1 were obtained. The relative standard deviation values were calculated to be lower than 4% and 8% for intra-day and inter-day, respectively. Finally, the developed method was successfully applied for the extraction and determination of mercury in various real samples. The satisfactory results revealed the capability of the proposed method in trace analysis without tedious derivatization or hydride generation.

Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots

A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4–cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with l-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV–Vis spectroscopy. The CL intensity of KMnO4–CdS QDs–CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4–CdS QDs–CTAB system and atenolol concentration in a range of 0.001 to 4.0mgL−1 and 4.0 to 18.0mgL−1, with a detection limit (3σ) of 0.0010mgL−1. A possible mechanism for KMnO4–CdS QDs–CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4–CdS QDs–CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol.

A flow injection chemiluminescence method for determination of nalidixic acid based on KMnO4–morin sensitized with CdS quantum dots

A simple and sensitive flow injection chemiluminescence (CL) method was developed for determination of nalidixic acid by application of CdS quantum dots (QDs) in KMnO4–morin CL system in acidic medium. Optical and structural features of l-cysteine capped CdS quantum dots which were synthesized via hydrothermal approach were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and ultraviolet–visible (UV–Vis) spectroscopy. Moreover, the potential mechanism of the proposed CL method was described using the results of the kinetic curves of CL systems, the spectra of CL, PL and UV–Vis analyses. The CL intensity of the KMnO4–morin–CdS QDs system was considerably increased in the presence of nalidixic acid. Under the optimum condition, the enhanced CL intensity was linearly proportional to the concentration of nalidixic acid in the range of 0.0013 to 21.0mgL−1, with a detection limit of (3σ) 0.003mgL−1. Also, the proposed CL method was utilized for determination of nalidixic acid in environmental water samples, and commercial pharmaceutical formulation to approve its applicability. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) method was utilized for determination of nalidixic acid and the results of real sample analysis by two proposed methods were compared. Comparison the analytical features of these methods represented that the proposed CL method is preferable to CD-IMS method for determination of nalidixic acid due to its high sensitivity and precision.

Comparison of two methods for selegiline determination: A flow-injection chemiluminescence method using cadmium sulfide quantum dots and corona discharge ion mobility spectrometry

Two analytical approaches including chemiluminescence (CL) and corona discharge ionization ion mobility spectrometry (CD-IMS) were developed for sensitive determination of selegiline (SG). We found that the CL intensity of the KMnO4–Na2S2O3 CL system was significantly enhanced in the presence of l-cysteine capped CdS quantum dots (QDs). A possible CL mechanism for this CL reaction is proposed. In the presence of SG, the enhanced CL system was inhibited. Based on this inhibition, a simple and sensitive flow-injection CL method was proposed for the determination of SG. Under optimum experimental conditions, the decreased CL intensity was proportional to SG concentration in the range of 0.01 to 30.0mgL−1. The detection limit (3σ) was 0.004mgL−1. Also, SG was determined using CD-IMS, and under optimum conditions of CD-IMS, calibration curves were linear in the range of 0.15 to 42.0mgL−1, with a detection limit (3σ) of 0.03mgL−1. The precision of the two methods was calculated by analyzing samples containing 5.0mgL−1 of SG (n=11). The relative standard deviations (RSDs%) of the flow-injection CL and CD-IMS methods are 2.17% and 3.83%, respectively. The proposed CL system exhibits a higher sensitivity and precision than the CD-IMS method for the determination of SG.

Determination of dexamethasone by flow-injection chemiluminescence method using capped CdS quantum dots

l-Cysteine capped CdS quantum dots (QDs) were synthesized through a facile hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and UV–Vis spectroscopy. The light emitted from KMnO4–l-cysteine capped CdS QDs reaction in acidic medium was applied as a simple and sensitive chemiluminescence (CL) system for determination of dexamethasone. The CL intensity of KMnO4–l-cysteine capped CdS QDs CL system was remarkably enhanced in the presence of dexamethasone. Under optimum experimental conditions, the enhanced CL intensity was related to dexamethasone concentration in the range of 0.004–25.0mgL−1, with the detection limit (3σ) of 0.0013mgL−1. The analytical applicability of the proposed CL system was assessed by determining dexamethasone in spiked environmental water samples and pharmaceutical formulation. The analytical performances of proposed flow-injection CL method for the determination of dexamethasone were compared with those obtained by corona discharge ionization ion mobility spectrometry (CD-IMS) method. The proposed CL system exhibits a higher sensitivity and precision than the CD-IMS method for the determination of dexamethasone.

A novel flow-injection chemiluminescence method for determination of baclofen using l-cysteine capped CdS quantum dots

l-Cysteine capped CdS quantum dots (QDs) were synthesized through a facile hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), and UV–vis spectroscopy. The l-cysteine capped CdS QDs sample displayed chemiluminescence (CL) emission in reaction with KMnO4 in acidic medium. It was found that the CL intensity of KMnO4–l-cysteine capped CdS QDs CL system was remarkably enhanced in the presence of Na2S2O3. Furthermore, the possible CL mechanism was presented for this CL reaction according to results of the kinetic curves of CL systems, the spectra of CL, PL and UV–vis. The CL intensity of KMnO4–l-cysteine capped CdS QDs–Na2S2O3 was strongly inhibited in the presence of baclofen. Based on this inhibition, a novel and sensitive flow-injection CL method was developed for the determination of baclofen. Under optimum conditions, the CL intensity was inversely proportional to the concentration of baclofen in the range of 0.012–24.0mgL−1, with a detection limit (3σ) of 0.0035mgL−1. The analytical applicability of the proposed CL system was assessed by determining baclofen in spiked environmental water samples and pharmaceutical formulation. The analytical performances of proposed flow-injection CL method for the determination of baclofen were compared with those obtained by corona discharge ionization ion mobility spectrometry (CD-IMS) method. The proposed CL system had a higher sensitivity than the CD-IMS method for the determination of baclofen.

Feasibility of corona discharge ion mobility spectrometry for direct analysis of samples extracted by dispersive liquid–liquid microextraction

The capability of corona discharge ionization ion mobility spectrometry (CD-IMS) for direct analysis of the samples extracted by dispersive liquid–liquid microextraction (DLLME) was investigated and evaluated, for the first time. To that end, an appropriate new injection port was designed and constructed, resulting in possibility of direct injection of the known sample volume, without tedious sample preparation steps (e.g. derivatization, solvent evaporation, and re-solving in another solvent…). Malathion as a test compound was extracted from different matrices by a rapid and convenient DLLME method. The positive ion mobility spectra of the extracted malathion were obtained after direct injection of carbon tetrachloride or methanol solutions. The analyte responses were compared and the statistical results revealed the feasibility of direct analysis of the extracted samples in carbon tetrachloride, resulting in a convenient methodology. The coupled method of DLLME-CD-IMS was exhaustively validated in terms of sensitivity, dynamic range, recovery, and enrichment factor. Finally, various real samples of apple, river and underground water were analyzed, all verifying the feasibility and success of the proposed method for the easy extraction of the analyte using DLLME separation before the direct analysis by CD-IMS.

Direct analysis of human breath ammonia using corona discharge ion mobility spectrometry

In this study, ammonia in human breath was directly determined using corona discharge ionization ion mobility spectrometry (CD-IMS) technique with several important advantages including high sensitivity, low cost, high speed, and ease of maintenance. The temperature effect on the ammonia signal was evaluated too. The results indicated that the best temperature for the investigation of breath ammonia was 150°C. The analytical results showed that the linear dynamic range was between 12 and 810ppb and the detection limit was 6.6ppb. The relative standard deviation (RSD) was obtained to be 5, 3, and 3 for 290, 348, and 522ppb, respectively. The amounts of ammonia in breath of eight healthy volunteers were measured. The values were between 236 and 1218ppb. Also, the inequality in breath ammonia levels was scrutinized over a 6h working day for three healthy volunteers. The results showed a drop in breath ammonia from the morning amount to the mid-day measurement and then, a progressive increase while the day continued. In addition, the amounts of ammonia were determined to be 1494–1553ppb in exhaled breath of two renal failure patients. The results obtained in this work revealed that the method was conveniently established without any considerable sample pretreatment for direct analysis of ammonia in human breath.

Design for Gas Chromatography–Corona Discharge–Ion Mobility Spectrometry

A corona discharge ionization-ion mobility spectrometry (CD-IMS) with a novel sample inlet system was designed and constructed as a detector for capillary gas chromatography. In this design, a hollow needle was used instead of a solid needle which is commonly used for corona discharge creation, helping us to have direct axial interfacing for GC-IMS. The capillary column was passed through the needle, resulting in a reaction of effluents with reactant ions on the upstream side of the corona discharge ionization source. Using this sample introduction design, higher ionization efficiency was achieved relative to the entrance direction through the side of the drift tube. In addition, the volume of the ionization region was reduced to minimize the resistance time of compounds in the ionization source, increasing chromatographic resolution of the instrument. The effects of various parameters such as drift gas flow, makeup gas flow, and column tip position inside the needle were investigated. The designed instrument was exhaustively validated in terms of sensitivity, resolution, and reproducibility by analyzing the standard solutions of methyl isobutyl ketone, heptanone, nonanone, and acetophenone as the test compounds. The results obtained by CD-IMS detector were compared with those of the flame ionization detector, which revealed the capability of the proposed GC-IMS for two-dimensional separation (based on the retention time and drift time information) and identification of an analyte in complex matrixes.