Pollution caused by nitrogen oxides (NOx, mainly NO and NO2) has attracted considerable attention due to its negative implications on the environment and human health. Herein, a novel, portable, and battery-operated system integrating a purge and trap (P&T) system with a miniaturized point discharge optical emission spectrometer (mu PD-OES) was developed for monitoring atmospheric NOx. Among NOx, NO2 can be selectively and directly absorbed by sodium hydroxide (NaOH) solution and converted to nitrite (NO2-). In contrast to NO2, NO cannot be absorbed by NaOH and must be oxidized to NO2 by KMnO4 prior to its absorption. When NO2 and NOx samplers were exposed simultaneously, NO can be calculated as the difference. The concentration of NOx in the air was determined by analyzing the NO2-. The obtained NO2- solution was purged with an argon carrier gas at a rate of 400 mL min- 1 for 5 min to remove all the volatile organic compounds contained in the solution before reacting with cyclamate to generate volatile cyclohexene, which was efficiently isolated and preconcentrated by P&T. Subsequently, the cyclohexene was desorbed from the P&T unit and swept into the mu PD-OES for its detection under optimized conditions. The system demonstrated a detection limit of 0.02 ppbv (0.04 mu g/m3) for NO2, surpassing conventional methods. Precision expressed as the relative standard deviation (RSD, n = 11) was better than 3.5 %. The system was validated by analyzing two NO2 standard gases and fourteen ambient air samples, and the obtained analytical results demonstrated its promising potential for rapid, sensitive, and precise NOx evaluation and monitoring.

Total organic carbon (TOC) is a crucial indicator of organic pollutants, widely used in environmental water quality monitoring and risk assessment. Conventional TOC detection methods often require high temperatures, complex equipment, and inefficient oxidation processes, limiting their field application due to time consumption, intricate operations, and limited sensitivity. Therefore, we developed a novel approach for TOC measurement using catalytic oxidation vapor generation coupled with miniaturized point discharge optical emission spectrometry (mu PD-OES). This method employs urchin-like Co3O4 microspheres to convert organic pollutants to carbon dioxide during persulfate catalytic oxidation, followed by collection and quantification via carbon atomic emission line (lambda = 193.0 nm). Standard or sample solutions were acidified with phosphoric acid and purged with Ar before quantification. Under optimal conditions, the proposed method achieved a detection limit of 0.01 mg L-1, offering precision (RSD, n = 11) better than 3.7 %. The feasibility of the system was tested using a certified reference material (GBW(E)082053) and environmental water samples, achieving satisfactory recoveries (98-102 %). This method provides high oxidation efficiency, sensitivity, and accuracy, while also reducing the demand for expensive and bulky instruments and minimizing energy consumption, making it suitable for rapid, sensitive field analysis of TOC.

The inherent instability of dissolved sulfide, leading to volatilization and oxidation during transport and storage, significantly compromises the accuracy of its detection. To address this limitation, the highly efficient extraction and preservation of sulfide in the field are essential. Herein, a simple field preconcentration and preservation method using ZIF-8 paper as a monolithic adsorbent coupling to a new dielectric barrier discharge microplasma assisted oxidation gas molecular fluorescence spectrometry was developed for highly sensitive detection of sulfide in environmental samples. The ZIF-8 paper was constructed as a monolithic adsorbent material through the in-situ growth of ZIF-8 on a carboxymethylated filter paper, which facilitates the straightforward and efficient adsorption and desorption of sulfide, offering excellent capability for the field extraction and long-term preservation of sulfide up to five days. The sensitive dielectric barrier discharge microplasma-molecular fluorescence spectrometry detection of sulfide was accomplished with a 3D-printed chemical vapor generation and dielectric barrier discharge microplasma assisted oxidation system. The system was not only employed to convert desorbed sulfide into H2S gas, but also used to further oxidize it to SO2 prior to its introduction to molecular fluorescence spectrometry. Under optimal conditions, the method achieved a limit of detection (LOD) of 0.1 μM and a relative standard deviation (RSD, n = 11) of 5.0 % at 20 μM of sulfide. The accuracy of this method was validated by two certified reference materials and several real environmental water samples. By coupling ZIF-8 paper preconcentration with chemical vapor generation-dielectric barrier discharge microplasma-molecular fluorescence spectrometry, this approach provides enhanced sensitivity, exceptional reliability, and robust performance for sulfide detection in complex environmental water matrices.

It is still challenging to perform a high-throughput digestion on limited amounts of sample prior to elemental analysis by atomic spectrometry. Herein, a photochemical reactor consisting of a quartz tube inserted into a low-pressure mercury lamp was used to fabricate a flow droplet photodigestion (FD-PD) device for the high-throughput digestion of small amounts of samples. A mixture containing 20 μL of blood sample, 20 μL of H2O2, and 10 μL of HNO3 was pumped and passed through the reactor before its online analysis by hydride generation atomic fluorescence spectrometry (HG-AFS). The developed photochemical reactor provides significantly higher oxidation capability than conventional ultraviolet (UV) photochemical reactor since the vacuum UV irradiation below 200 nm from the mercury lamp directly irradiates samples with high transmittance, enabling complete digestion within 2 min. Compared to conventional digestion methods, the proposed method retains several unique advantages of higher sample throughput (57 pcs h-1), lower sample, mineral acid, and oxidant consumption, and shorter digestion time, facilitating painless blood analysis for children. Limits of detection (LODs) of 0.25 and 0.15 μg L-1 were obtained for As and Hg, respectively, with precisions (relative standard deviations (RSDs), n = 11, 2.0 μg L-1) better than 4%. The practicality of FD-PD-HG-AFS was confirmed by detecting As and Hg in one blood and two urine certified reference materials (CRMs), as well as several children's blood samples with satisfactory recoveries (93%-109%).

Despite the significant importance of blood lithium (Li) detection in the treatment of bipolar disorder (BD), its point-of-care testing (POCT) remains a great challenge due to tedious sample preparation and the use of large-footprint atomic spectrometers. Herein, a system coupling dried blood spots (DBS) with a point discharge optical emission spectrometer equipped with a miniaturized ultrasonic nebulizer (MUN-mu PD-OES) was developed for POCT of blood Li. Three microliters of whole blood were used to prepare a dried blood spot on a piece of filter paper to which 10 mu L of eluent (1% (v/v) formic acid and 0.05% (v/v) Triton-X) was added. Subsequently, the paper was placed onto the vibrating steel membrane of the ultrasonic nebulizer and powered on to generate aerosol. The aerosol was directly introduced to the mu PD-OES for quantification of Li by monitoring its atomic emission line at 670.8 nm. The proposed method minimized matrix interference caused by high levels of salts and protein. It is worth noting that the MUN suitably matches the needs of DBS sampling and can provide aerosolized introduction of Li into the assembled mu PD-OES, thus eliminating all tedious sample preparation and the need for a commercial atomic spectrometer. Calibration response is linear in the therapeutic range and a limit of detection (LOD) of 1.3 mu g L-1 is well below the Li minimum therapeutic concentration (2800 mu g L-1). Li in mouse blood was successfully detected in real-time using MUN-mu PD-OES after intraperitoneal injection of lithium carbonate, confirming that the system holds great potential for POCT of blood Li for patients with BD.

Environmental mercury pollution poses a serious threat to public health and ecosystems, underscoring the value of rapid and accurate on-site mercury measurement technologies. Therefore, a portable mercury analyzer was developed with capillary point discharge for excitation and cold vapor generation for sample introduction. A limit of detection (LOD) of 0.23 mu g L-1 for mercury was achieved, relative standard deviations below 5 % were maintained in a 10-hour testing period. This method was successfully used for mercury determination of spiked water samples, fish meat, and laboratory wastewater. Powered by several power banks, it can be used to monitor mercury levels in water samples continuously over a working day. Compared with traditional technology, this one greatly reduces the size of the instrument, the consumption of working gas, and the construction cost, making it suitable for rapid field analysis of many types of samples for trace mercury.

BACKGROUND:The accurate determination of iodine in seawater is essential to understanding its impact on the environment and human health. Inductively coupled plasma mass spectrometry (ICP-MS) is a widely used technique for elemental analysis due to its high sensitivity, speed, and low limit of detection (LOD). However, its capability in the detection of iodine in complex matrix samples is still limited by the low sample introduction efficiency of pneumatic nebulization and the high ionization energy of iodine. Dielectric barrier discharge microplasma-induced vapor generation (DBD-μPIVG) is a sample introduction technique that has been widely coupled with atomic spectrometry due to its high vapor generation efficiency, rapid reaction speed, high anti-interference capability, and environmental friendliness. RESULTS:A new method was developed for the rapid and sensitive determination of iodine using DBD-μPIVG coupled with ICP-MS. The DBD-μPIVG sample introduction technique can convert both iodide and iodate to their volatiles with a vapor generation efficiency of 70 %. The experimental conditions were optimized in detail, and the LOD for iodine was 0.04 μg L-1, which was lower compared to pneumatic nebulization and comparable to that after the extraction treatment. The relative standard deviation (RSD) obtained after 11 replicate determinations was 2.4%. Furthermore, the potential mechanism and anti-interference performance of the proposed method were also carefully investigated. SIGNIFICANCE:Compared to other analytical methods for iodine analysis, this approach is environmentally friendly, exhibits high anti-interference capability and enables accurate determination of iodine in complex matrix samples. The high vapor generation efficiency of DBD-μPIVG improves the sensitivity for iodine detection and expands the applicable elemental range of DBD-μPIVG. Finally, the proposed method was successfully applied to analyze the iodine content in seawater samples obtained from the Chinese coastal waters and retains great potential for assessing the distribution of iodine in different sea areas.

To enhance sample throughput and avoid environmental pollution, it is crucial to develop anatomic spectrometry method for the direct and sensitive detection of heavy metals in soil samples. In this work, a portable analytical device integrating electromagnetic heating evaporation (EMHV), purge-and-trap (P&T), and miniature point discharge optical emission spectrometry(mu PD-OES) was developed to determine mercury in soil without chemical pretreatment. This method involves converting soil mercury species into cold mercury vapor (Hg-0), which is then evaporated from the sample using a low-power miniaturized EMHV device. The generated Hg0is subsequently separated and trapped in a tube filled with gold-sand before mu PD-OESanalysis.This process not only preconcentrates the analyte but also achieves complete matrix separation before analysis, thereby reducing matrix interference and enhancing the sensitivity of the mercury detection. Under optimal experimental conditions, the limit of determination (LOD) for mercury was established at 0.25 mu gkg(-1) with a relative standard deviation (RSD) of 3.6%anda sample consumption of 60 mg. The accuracy and practicality of the EMHV-P & T-mu PD-OES method were validated through the determination of mercury in two soil certified reference materials (CRMs) and five real soil samples. The analytical results agree well with the certified values of the CRMs, confirming the practicality of the proposed analytical system for soil mercury analysis.

BACKGROUND:Arsenic contamination of drinking water has become a public health challenge over the world, particularly in Bangladesh, India, and China. Compared to the most used field test kits of waterborne arsenic, miniature microplasma atomic spectrometry retains advantages of accuracy, elemental specificity, and less matrix interference. Despite increased interest in arsenic detection by using miniature microplasma spectrometry, the improvements of its analytical performance, manufacturing cost and consistency still remain significant challenges. RESULTS:Herein, a miniature, battery-operated, and integrated hydride generation point discharge optical emission spectrometer (HG-μPD-OES, 116 mm length × 92 mm width × 104 mm height) was printed with a simple 3D printer and used for the highly sensitive and element-specific determination of arsenic by coupling to a dispersive solid-phase extraction (d-SPE) using zeolitic imidazolate framework-8 as adsorbent. The d-SPE simplifies sample treatment, significantly alleviates the interference arising from transition metal ions and improves sensitivity. A LOD of 0.07 μg L-1 for arsenic was obtained with relative standard deviations (RSDs, n = 11) better than 3.8 %. SIGNIFICANCE:The 3D printing technique significantly improves the manufacturing cost and fabricating consistency of HG-μPD-OES. LOD were remarkably improved 27-fold compared to those obtained by conventional HG-μPD-OES, providing a promising method for the reliable, sensitive, and convenient field analysis of waterborne arsenic even its concentration as low as 0.2 μg L-1. The practicability and accuracy of the proposed method have been successfully verified via the field analysis of waterborne arsenic in a Certified Reference Material (GBW(E)080390) and a series of river and lake water samples.

Most of the available methods for the quantification of cyclamate depend on laboratory instruments and their application in the field was limited. Herein, a simple and sensitive method was developed for the determination of cyclamate in beverage samples based on chemical vapor generation and miniature point discharge optical emission spectrometry (mu PD-OES). The combination of headspace sampling and mu PD-OES not only simplifies the separation process of cyclamate, improves sensitivity, and alleviates matrix interference but also eliminates the use of a bulky and expensive instrument. Under the optimal conditions, this method provided a limit of detection of 0.1 mg L-1 comparable to or better than most reported methods. The method eventually was applied to 14 different beverages and cyclamate was found below the threshold set by Chinese Standards for Food Additives. The proposed method provides great potential for the field analysis of cyclamate in the supervision of food safety.

简便、快速、可操作性强的样品前处理方法是小型化原子光谱仪现场应用的关键.本实验构建了一种基于二氧化钛纳米管阵列(TiNTs)的手持式搅拌吸附仪,结合氢化物发生尖端放电微等离子体原子发射光谱法(HG-μPD-OES)对水中的砷进行现场分析.采用阳极氧化法合成TiNTs吸附片,将吸附片装载在小型搅拌电机上组成手持式自动化搅拌吸附仪,对地表水中的砷进行快速富集.富集后的砷经氢氧化钠溶液解析后泵入反应管中进行氢化物发生反应,生成的挥发性产物被载气吹扫进入尖端放电微等离子体中进行激发,采用手持式电荷耦合器件(CCD)采集砷的特征发射线及强度实现定性定量分析.在最优实验条件下,砷的检出限为0.02μg·L-1,相对标准偏差优于6.5％,富集因子为53.4.通过对成都市多个河流湖泊进行水砷现场测定,并与ICP-MS的测定结果对比,验证了本方法的实用性和准确性,为快速、准确、灵敏的水砷现场分析提供了广阔的应用前景.

The determination of volatile methylsiloxanes (VMSs) in municipal sewage has attracted great attention. Gas chromatography-mass spectrometry (GC-MS) is the most mature detection technique for VMSs, however, its instrumentation and operation cost are unfavorable in low- and middle-income countries. Herein, a novel and cost-effective strategy by using a 3D printed miniature microplasma optical emission detector (mu AED) as an alternative to MS detector, was developed to detect VMSs in municipal sewage by GC after preconcentration by a laboratory-built automatic purge and trap (P&T) system. Two types of mu AEDs have been fabricated and their analytical performances were compared. The one using two tungsten rods as electrodes shows better performance and was thus selected as the detecting system for real sample analysis. Under the optimized conditions, the P & T-GC-mu AED system provided limits of detection of 3.6 ng L-1 to 15.5 ng L-1 of Si for tested VMSs. Relative standard deviations were better than 3.0% and good recoveries ranging from 82.4% to 102.8% were obtained for all analytes. The applicability of this system was demonstrated via the measurement of VMSs in the influents and effluents from 10 wastewater treatment plants (WWTPs) in Chengdu, China. (C) 2021 Elsevier B.V. All rights reserved.

A simple method coupling liquid-liquid extraction (LLE) with 3D printed cold vapor generation point discharge microplasma optical emission spectrometry (CVG-mu PD-OES) was constructed for the speciation analysis of mercury in fish oil. Mercury species contained in fish oil (mainly inorganic mercury (IHg) and methylmercury (MeHg)) were efficiently extracted into an aqueous medium containing 1.5% (m/v) L-Cysteine and 1% (m/v) ammonium acetate after a 3 min of vortex oscillation. Subsequently, the aqueous extracted solution was analyzed by CVG-mu PD-OES. IHg was reduced to mercury cold vapor (Hg0) by the reaction with 0.02% (m/v) KBH4 in the absence of KMnO4, whereas total mercury (MeHg and IHg) could be converted to Hg0 by CVG after the preoxidation of KMnO4. All the generated Hg0 was separated from the condensed liquid phase and analyzed by mu PD-OES. Under optimal experimental conditions, limits of detection (LODs) were found to be 0.1 mu g L-1 for both MeHg and IHg, with relative standard deviations (RSDs, n = 11) of better than 4.3%. Two Certified Reference Materials (CRMs) and eight fish oils were analyzed to validate the accuracy and applicability with good recoveries (84%-114%). Since the 3D printing technique significantly decreases its instrument manufacturing difficulty and LLE improves its analytical performance, the LLE-CVG-mu PD-OES featured portability, simplicity, low energy consumption, and high sensitivity, showing a promising prospect for the rapid and accurate safety assessment of fish oil and its relevant dietary supplements.

A highly efficient Rh(III)-catalyzed tandem [4+2] annulation to construct functional dihydroisoquinolinone derivatives with an alkenyl side chain by insertion into an N-O bond as an internal oxidation process has been achieved. A wide range of 1,3-dienes as the coupling partners makes this simple methodology even more useful.

Inspired by the headspace sampling (HS) device, a versatile high-throughput photochemical reactor with twenty vessels serving as both the photochemical vapor generator and the HS device was developed for the rapid and sensitive determination of mercury, nickel, and selenium by coupling photochemical vapor generation (PVG) to atomic fluorescence spectrometry (AFS) or point discharge optical emission spectrometry (μPD-OES). The photochemical reactor utilized a specially designed annular UV lamp around which the vessels containing sample solution were automatically rotated and irradiated to yield gaseous analyte species. Subsequently, the species escaped into the headspace of vessels prior to introduction to the atomic spectrometer. Compared with the conventional flow injection (FI) or continuous flow (CF) PVG, the developed PVG-HS method possesses several unique advantages including high throughput (260 pcs h-1), high sensitivity, and the elimination of matrix interference from transition metal ions and the memory effect associated with the quantification of mercury. Limits of detection (LODs) of 0.002, 0.007, and 0.01 μg L-1 were obtained for Hg (II), Ni (II), and Se (IV) by PVG-HS-AFS, respectively, and 0.02 and 0.2 μg L-1 were obtained for Hg (II) and Ni (II) by PVG-HS-μPD-OES, respectively. The practicality of the reactor was evaluated by the detection of Hg (II), Ni (II), and Se (IV) in five certified reference materials, including water (GBW08603, GBW08607, and GBW(E)080395), National Research Council Canada dogfish liver (DOLT-5), fish protein (DORM-4), and three river water samples with good recoveries (92-106%).

Despite increased interest in microplasma-induced vapor generation (μPIVG) over the past several years, applications in real sample analyses remain limited due to their relatively low vapor generation efficiency and ambiguous mechanism. In this work, a novel method using methanol for significantly enhancing the liquid electrode discharge μPIVG efficiency was developed for the simultaneous and sensitive determination of Hg, Cd, and Zn by atomic fluorescence spectrometry (AFS). It is worth noting that the possible enhancement mechanism was investigated via the characterizations of volatile products by AFS, microplasma optical emission spectrometry, online gas chromatography, and gas chromatography-mass spectrometry, which involved the reductive species such as electrons, hydrogen radicals (·H), methyl radicals (·CH3), and other intermediates in the argon plasma adding methanol. Under the optimized conditions, the limits of detection of 0.007, 0.05, and 0.5 μg L-1 were obtained for Hg, Cd, and Zn, respectively, with relative standard deviations of 3.1, 3.7, and 5.2% for these elements, respectively. Vapor generation efficiencies of 90, 83, and 55% were achieved for Hg, Cd, and Zn, respectively, and improved 2.7-, 4.8-, and 7.9-fold, respectively, compared to those obtained in the absence of methanol. The accuracy and practicability of the proposed method were validated by the determination of Hg, Cd, and Zn in a certified reference material (CRM, Lobster hepatopancreas, TORT-3) and crayfish samples collected from three different provinces of China.

An efficient asymmetric Mannich/cyclization cascade strategy was established from 2-benzothiazolimines with N-acylpyrazoles to provide optical active benzothiazolopyrimidine derivatives using a copper-based complex. The mild cascade process constructed various structurally diverse products with broad scope of substrates together with excellent enantioselectivities (up to 99 % ee) and diastereoselectivities (up to 99:1 d.r.).

A method for the rapid screening of toxic elements in fruits and vegetables is of significant importance to prevent human exposure to these elements. In this work, a simple method used for microplasma-induced vapor generation (μPIVG) was developed for the rapid screening and quantification of mercury in fruits and vegetables without sample preparation. A stainless-steel capillary was partly inserted into a juice droplet from the tested fruits and then the sample liquid automatically moved to the end of the capillary with the assistance of inherent capillary driving force. Subsequently, a high voltage was applied between the capillary and a tungsten electrode to generate microplasma wherein the juice was sprayed and the mercury ions contained in the juice were converted to mercury cold vapor (Hg0). The Hg0 was finally separated from the liquid phase and swept to an atomic fluorescence spectrometer (AFS) for rapid screening. A standard addition method coupled with μPIVG atomic fluorescence spectrometry was further used for the quantitative analysis of the suspected sample. Under the optimized conditions, the limits of detection (LODs) of 0.3, 0.5, and 0.4 μg L-1 were obtained for the tested tomato, lemon, and orange samples, respectively. The proposed technique provides a simple and cost-effective tool for the rapid screening of mercury in fruits and vegetables by atomic spectrometry.

A new chemical vapor generation method coupled with headspace solid-phase microextraction miniaturized point discharge optical emission spectrometry (HS-SPME-μPD-OES) for the sensitive and matrix effect-free detection of nitrite in complex samples is described. In an acidic medium, the volatile cyclohexene was generated from cyclamate in the presence of nitrite, which was volatilized to the headspace of the container, efficiently separated, and preconcentrated by HS-SPME. Consequently, the SPME fiber was transferred to a laboratory-constructed thermal desorption chamber wherein the cyclohexene was thermally desorbed and swept into μPD-OES for its sensitive quantification via monitoring the carbon atomic emission line at 193.0 nm. As a result, the quantification of nitrite was accomplished through the determination of cyclohexene. The application of HS-SPME as a sampling technique not only simplifies the experimental setup of μPD-OES but it also preconcentrates and separates cyclohexene from N2 and sample matrices, thus eliminating the interference from water vapor and N2 and significantly improving the analytical performance on the determination of nitrite. Under the optimum experimental conditions, a limit of detection of 0.1 μg L-1 was obtained, which is much better than that obtained by conventional methods. The precision, expressed as relative standard deviation, was better than 3.0% at a concentration of 10 μg L-1. The proposed method provides several advantages of portability, simplicity, high sensitivity, and low energy consumption and eliminates expensive instruments and matrix interference, thus retaining a promising potential for the rapid, sensitive, and field analysis of nitrite in various samples.

The ruthenium-catalyzed remote ε-C-H alkylation of phosphines with tertiary alkyl halides has been developed. This novel PIII-directed C-H activation strategy tolerated various functional groups and delivered a wide variety of modified phosphines with excellent meta-site selectivity. Preliminary mechanistic studies indicated that a PIII-assisted ortho-cyclometalation/remote σ-activation pathway might be involved in this methodology.