Development of a Portable Method for Serum Lithium Measurement Based on Low-Cost Miniaturized Ultrasonic Nebulization Coupled with Atmospheric-Pressure Air-Sustained Discharge

Electrothermal desolvation-enhanced microplasma optical emission spectrometry for sensitive determination of Cd, Zn Pb and Mn in environmental water samples

Herein, a novel electrothermal desolvation (ED) introduction approach is developed to enhance the analytical sensitivity of the point discharge (PD)-based microplasma-optical emission spectrometric (PD-MIP-OES) system for detecting trace Cd, Zn, Pb and Mn in environmental water samples. Liquid samples are converted into aerosols through a miniature ultrasonic nebulizer, and subsequently desolvated by electric heating at 350 °C. The analytes obtained after condensation (referring to the smaller apertures aerosols and volatile analytes after ED and condensation) are excited and detected by PD-MIP-OES. For a 160 μL liquid sample, analysis is completed within 10 s, achieving a desolvation efficiency of 93 %. Under the optimized conditions, the detection limits for Cd, Zn, Pb and Mn are 1.3, 1.2, 2.4 and 2.1 μg L-1, respectively. Compared to traditional direct ultrasonic nebulization introduction, sensitivity increases by 17, 12, 10 and 14 times, respectively. The accuracy and practicality of the proposed method are verified by measuring certified reference material and several real water samples. The ED-enhanced PD-MIP-OES device presented is compact, easy to operate, and capable of rapid analysis, which provides a convenient and reliable tool for the field analysis of Cd, Zn, Pb and Mn in environmental water samples.

On-Site Portable Lithium Detection in Mining and Recycling Industries Based on a DNAzyme Fluorescent Sensor

The global demand for lithium has soared in recent years due to the wide use of lithium batteries. To meet this demand, we herein report developing novel on-site sample preparation methods for the extraction of Li+ from relevant materials, including brine water, spodumene rock, as well as lithium-ion battery electrodes, and a DNAzyme-based fluorescent sensor for sensitive and robust detection of Li+ in these samples down to 1.4 mM (10 ppm) using a portable fluorometer. The system can distinguish key threshold lithium levels that indicate economic value across several industries, including 200 ppm Li+ for brine mining, 6 % Li2O or SC6 for rock mining, and Li+-specific aging in LIBs. The methods developed and demonstrated in this work will allow highly selective, on-site, portable detection of lithium in both environmental samples to identify new lithium resources and in battery electrodes to guide recycling strategies in order to meet the global demand for lithium.

Low-Consumption and High-Efficiency Isotope Analysis by Microultrasonic Single-Droplet Nebulization Sampling Multicollector Inductively Coupled Plasma Mass Spectrometry

Metal stable isotopes are increasingly applied in various fields, including planetary science and medical research, highlighting the need for isotope analysis methods capable of handling precious and microvolume samples. This study introduces a novel, low-consumption, high-efficiency isotope analysis method using MC-ICP-MS based on microultrasonic single-droplet nebulization (MUSDN). The proposed MUSDN enables the complete nebulization of microliter-sized droplets, delivering high-sensitivity transient analytical signals with a duration of several seconds. Under optimized conditions, MUSDN exhibited significantly enhanced sensitivity compared to conventional pneumatic nebulization, achieving 17-fold and 12-fold improvements for 7Li and 63Cu, respectively. The achieved external precisions (2SD) for δ7Li and δ65Cu were 0.3 and 0.08‰, with single analysis consuming only 1 ng of Li and 2 ng of Cu, respectively. This represents a reduction in sample consumption by 1-2 orders of magnitude compared to conventional PN-MC-ICP-MS while also improving the analysis speed by at least 10-fold due to rapid residual washout. Furthermore, our method demonstrated superior δ65Cu analytical precision compared to other high-sensitivity transient analysis methods (0.19‰ with a laser ablation system) with similar sample consumption. Finally, the accuracy of the proposed method was validated through the analysis of geological CRMs, serum CRMs, in-house standard samples, and a series of real serum samples. This novel isotope analysis method provides a promising approach for isotope applications involving precious and microvolume samples.

Miniature mass spectrometers and their potential for clinical point-of-care analysis

Mass spectrometry (MS) has become a powerful technique for clinical applications with high sensitivity and specificity. Different from conventional MS diagnosis in laboratory, point-of-care (POC) analyses in clinics require mass spectrometers and analytical procedures to be friendly for novice users and applicable for on-site clinical diagnosis. The recent decades have seen the progress in the development of miniature mass spectrometers, providing a promising solution for clinical POC applications. In this review, we report recent advances of miniature mass spectrometers and their exploration in clinical applications, mainly including the rapid analysis of illegal drugs, on-site monitoring of therapeutic drugs, and detection of biomarkers. With improved analytical performance, miniature mass spectrometers are also expected to apply to more and more clinical applications. Some promising POC analyses that can be performed by miniature mass spectrometers in the future are discussed. Lastly, we also provide our perspectives on the challenges in technical development of miniature mass spectrometers for clinical POC analysis.

Dried Blood Spots and Miniaturized Ultrasonic Nebulization Microplasma Optical Emission Spectrometry for Point-of-Care Testing of Blood Lithium

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-μPD-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 μL 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 μPD-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 μPD-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 μg L-1 is well below the Li minimum therapeutic concentration (2800 μg L-1). Li in mouse blood was successfully detected in real-time using MUN-μPD-OES after intraperitoneal injection of lithium carbonate, confirming that the system holds great potential for POCT of blood Li for patients with BD.

Existing and Emerging Technologies for Therapeutic Monitoring of Lithium: A Scoping Review

BACKGROUND/PURPOSE

Lithium is an effective psychoactive drug. It has a narrow therapeutic margin, with subtherapeutic levels or intoxication commonly occurring. Therapeutic drug monitoring (TDM) of lithium has several barriers. This scoping review aims to describe and analyze existing and emerging technologies for lithium TDM and to describe the lithium quantification parameters (precision, accuracy, detection limit) attributed to each technology.

METHOD

PubMed, Scopus, Web of Science, and Google Scholar were searched. Studies that described lithium quantification and complied with PRISMA-ScR guidelines were included. Articles selection was conducted by 2 researchers. Good precision was defined if its relative standard deviation <3%; acceptable, from 3% to 5%; and low, >5%. Accuracy was considered good if the error <5%; acceptable, 5%1 to 0%; and low if it was >10%.

RESULTS

Of the 2008 articles found, 22 met the inclusion criteria. Of these, 14 studies concerned laboratory devices, in which precision was found to be low in one third of cases, and half had good precision. Accuracy of one third was good, another third was low, and the remaining third did not report accuracy. The other 8 studies concerned portable devices, in which precision was low in more than 60% of the cases and good in 25% of the studies. Accuracy was low in 50% of the cases, and good in just over a third. Limits of detection included the therapeutic range of lithium in all studies.

CONCLUSIONS

Among emerging technologies for lithium TDM, precision and accuracy remain a challenge, particularly for portable devices.

Lithium sensors based on photophysical changes of 1-aza-12-crown-4 naphthalene derivatives synthesized via Buchwald-Hartwig amination

Lithium detection is of great significance in many applications. Lithium-sensing compounds with high selectivity are scarce and, if any, complicated to synthesize. We herein report a novel yet simple compound that can detect lithium ions in an organic solvent through changes in absorbance and fluorescence. Naphthalene functionalized with 1-aza-12-crown-4 (1) was synthesized via one step from commercially available 1-bromonaphthalene through Buchwald-Hartwig amination. In order to obtain a structure-property relationship, we also synthesized two other compounds that are structurally similar to 1, wherein the compounds 2 and 3 include an imide moiety (an electron acceptor) and do not include a 1-aza-12-crown-4 unit, respectively. Upon the addition of lithium ions, compound 1 displayed a clear isosbestic point in the absorption spectra and a new peak in the fluorescence spectra, whereas the compounds 2 and 3 indicated miniscule and no spectroscopic changes, respectively. 1H NMR titration studies and the calculated optimized geometry from density functional theory (DFT) indicated the lithium binding on the aza-crown. The calculated limit of detection (LOD) was 21 μM. The lithium detection with 1 is selective among other alkali metals (Na+, K+, and Cs+). DFT calculation indicated that the lone pair electrons in the nitrogen atom of 1 is delocalized yet available to bind lithium, whereas the nitrogen lone pair electrons of 2 showed significant intramolecular charge transfer to the imide acceptor, resulting in a high dipole moment, and thus were unavailable to bind lithium. This work elucidates the key design parameters for future lithium sensors.

A microplasma optical emission spectrometry pen for point-of-care diagnosis of child blood lead

Blood lead levels (BLL) of children have attracted considerable attention due to their putative impact on intelligence decline. However, most methods used for the determination of blood lead typically require expensive, bulky, high power and gas consuming instrumentation, limiting their application for a point-of-care diagnosis. Herein we report the development and testing of a portable ballpoint discharge microplasma optical emission spectrometer (BD-OES pen) device having the potential to fill this needed measurement capability. The BD-OES pen utilizes a compact ballpoint-pen format integrating point-discharge microplasma, which permits the determination of child BLL requiring no more than 100 μL blood while providing high specificity, sensitivity and satisfactory limit of detection (0.73 μg L^-1). The handheld BD-OES pen is successfully used to diagnose BLL of 16 asymptomatic children on-site, two of whom had excessive the normal BLL. The pen may aid the on-site and rapid diagnosis of childhood BLL, particularly in low-income areas.