Automated ICP-MS method to measure bromine, chlorine, and iodine species and total metals content in drinking water

Quantitative native speciation of ppb-level metals in semiconductor-manufacturing-used strong acids and a base

The presence of metal species in solvents significantly impacts production yields in the semiconductor industry, particularly as the dimensions of integrated circuits continue to decrease. Therefore, it is imperative to control metal concentrations in solvents to levels as low as a few parts per billion (ppb) throughout fabrication processes. Effective purification methods are essential for removing various levels of contamination, and understanding the speciation of metals is crucial for achieving efficient purification. Conventional methods for the speciation of solution-phase metals include ion chromatography (IC) and ultraviolet-visible (UV-Vis) absorption spectroscopy. However, these techniques present limitations; for instance, IC can inadvertently alter species during the elution process, while the requirement for high-purity parts per million (ppm) concentrations of metals obscures the speciation of trace mixed samples using UV-Vis absorption spectroscopy. In this study, we present a quantitative speciation method for metals in their native states within strong acids and a base, utilizing the breakthrough curve (BTC) theory in conjunction with inductively coupled plasma-mass spectrometry (ICP-MS). Sodium, potassium, magnesium, calcium, iron, and copper serve as model systems for our investigations. The combination of BTC and ICP-MS provides insights into the species present and their respective abundances. Our findings indicate that breakthrough time (tBT) is predominantly influenced by the charge states and binding selectivity of the metal species and the concentrations of competing binding species. For scenarios where the product of the adsorption equilibrium constant (K) and the concentrations of a species at equilibrium (C) is significantly less than one (KC ≪ 1), tBT serves as a critical metric for assessing metal species at trace levels. Taking sodium (I) and potassium (I) at 10 ppb as representative examples, we discovered that tBT was accelerated by a factor of 5.7 when the concentration of the competing binding species ([H]+ in this study) was increased five-fold from 0.02 M to 0.1 M nitric acid (HNO3). Specifically, the tBT for sodium (I) decreased from 23 min to 4 min, while for potassium (I), it dropped from 114 min to 20 min. Furthermore, in the cases of magnesium (II) and copper (II) at 10 ppb, tBT was expedited by a factor of approximately 25; the tBT for magnesium (II) fell from 100 min to 4 min, and for copper (II), it decreased from 157 min to 6 min when the [H]+ concentration was increased five-fold from 0.1 M to 0.5 M HNO3. Additionally, we observed distinct species transformations for iron and copper, evidenced by markedly altered tBT in 0.1 M choline hydroxide solutions, which was observed to be less than 10 min. Anionic iron complexes and neutral copper particles were inferred, supported by ion exchange and UV-Vis absorption spectroscopic measurements. Furthermore, copper particles, potentially identified as copper (II) hydroxide or copper (II) oxide, exhibited a size distribution ranging from 200 to 400 nm with a peak at 300 nm, as characterized using particle analyzers. The advantages of the BTC theory-facilitated native quantitative speciation are anticipated to enhance informed decision-making for optimizing purification processes within the semiconductor industry.

Chemical Characterization in Medical Device Evaluation: Current Practices, Regulatory Requirements, and Future Directions

The rigorous regulatory landscape for medical devices demands meticulous chemical characterization to ensure safety and compliance. This review examines the critical role of chemical characterization within regulatory frameworks, emphasizing its importance in the approval and market entry of medical devices. Key challenges, including the complexity of sample matrices, trace-level impurity detection, and the necessity of method validation, are thoroughly explored. In addition, the review addresses the dynamic nature of regulatory requirements, analyzing how updates in international standards, such as those from the International Organization for Standardization (ISO), the American National Standards Institute (ANSI), and the Association for the Advancement of Medical Instrumentation (AAMI), or the American Society for Testing and Materials (ASTM), shape the chemical characterization process. The review discusses future directions, including advancements in analytical technologies, the potential for increased automation and standardization, and the growing significance of managing emerging contaminants. By offering a comprehensive analysis of current practices and future trends, this review highlights the essential role of chemical characterization in ensuring the development and regulation of safe and effective medical devices.

Determination of iodide in concentrated chloride springs by reversed-phase high-performance liquid chromatography with ultraviolet detection

We developed a convenient and simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method for analysis of iodide in concentrated chloride springs. Using a C18 column, the iodide and chloride peaks were well separated. Setting the wavelength at 240 nm allows direct ultraviolet (UV) detection of iodide without any UV or Schlieren effect due to the high chloride concentration. The high ionic strength of spring samples containing high levels of sodium chloride broadens the iodide peak. Iodide was quantified based on the peak areas of standard solutions of iodide, in which 100 mM sodium chloride was added to match the saline matrixes with the samples. The detection limit of iodide at a signal-to-noise ratio of 3 was 0.0003 mM. The detector response was linear over the concentration ranges of 0.001-0.1 mM. The proposed RP-HPLC/UV method was successfully applied to determine iodide in some concentrated chloride spring samples.

Application of Online Multi-Internal Standard Calibration for Determination of Iodine by ICP-MS

This study presents a comprehensive evaluation of the application of online multi-internal standard calibration (M.ISC) in determining iodine concentrations through inductively coupled plasma mass spectrometry (ICP-MS). Notably, M.ISC streamlines the calibration process by requiring only a single standard solution, thereby enhancing sample throughput and minimizing liquid waste. In addition, unlike conventional internal standard (IS) methods, M.ISC omits the need for time-consuming species identification by utilizing multiple IS species simultaneously to minimize signal biases. The effectiveness of M.ISC was validated through the analysis of six standard reference samples, with the results of LOD and LOQ also being calculated by the error propagation approach. The traditional chemical analytical methods (TCAM), external standard calibration (EC) and single IS methods were also evaluated as comparative purpose. Nonetheless, M.ISC emerges as a straightforward matrix-correction strategy, offering a simple and efficient alternative to traditional calibration methods for iodine detection by ICP-MS.

Quantification of [99Tc]TcO4- in urine by means of anion-exchange chromatography-aerosol desolvation nebulization-inductively coupled plasma-mass spectrometry

To sensitively determine 99Tc, a new method for internal quantification of its most common and stable species, [99Tc]Tc O 4 - , was developed. Anion-exchange chromatography (IC) was coupled to inductively coupled plasma-mass spectrometry (ICP-MS) and equipped with an aerosol desolvation system to provide enhanced detection power. Due to a lack of commercial Tc standards, an isotope dilution-like approach using a Ru spike and called isobaric dilution analysis (IBDA) was used for internal quantification of 99Tc. This approach required knowledge of the sensitivities of 99Ru and 99Tc in ICP-MS. The latter was determined using an in-house prepared standard manufactured from decayed medical 99mTc-generator eluates. This standard was cleaned and preconcentrated using extraction chromatography with TEVA resin and quantified via total reflection X-ray fluorescence (TXRF) analysis. IC coupled to ICP-MS enabled to separate, detect and quantify [99Tc]Tc O 4 - as most stable Tc species in complex environments, which was demonstrated in a proof of concept. We quantified this species in untreated and undiluted raw urine collected from a patient, who previously underwent scintigraphy with a 99mTc-tracer, and determined a concentration of 19.6 ± 0.5 ng L-1. The developed method has a high utility to characterize a range of Tc-based radiopharmaceuticals, to determine concentrations, purity, and degradation products in complex samples without the need to assess activity parameters of 99(m)Tc.

Recent advances in removal of inorganic anions from water by chitosan-based composites: A comprehensive review

Chitosan is a modified natural carbohydrate polymer that has been found in the exoskeletons of crustaceans (e.g., lobsters, shrimps, krill, barnacles, crayfish, etc.), mollusks (octopus, oysters, squids, snails), algae (diatoms, brown algae, green algae), insects (silkworms, beetles, scorpions), and the cell walls of fungi (such as Ascomycetes, Basidiomycetes, and Phycomycetes; for example, Aspergillus niger and Penicillium notatum). However, it is mostly acquired from marine crustaceans such as shrimp shells. Chitosan-based composites often present superior chemical, physical, and mechanical properties compared to single chitosan by incorporating the benefits of both counterparts in the nanocomposites. The tunable surface chemistry, abundant surface-active sites, facilitation synthesize and functionalization, good recyclability, and economic viability make the chitosan-based materials potential adsorbents for effective and fast removal of a broad range of inorganic anions. This article reviews the different types of inorganic anions and their effects on the environment and human health. The development of the chitosan-based composites synthesis, the various parameters like initial concentration, pH, adsorbent dosage, temperature, the mechanism of adsorption, and regeneration of adsorbents are discussed in detail. Finally, the prospects and technical challenges are emphasized to improve the performance of chitosan-based composites in actual applications on a pilot or industrial scale.

A survey on heavy metal concentrations in residential neighborhoods: The influence of secondary water supply systems

Water quality deterioration often occurs in secondary water supply systems (SWSSs), and increased heavy metal concentrations can be a serious problem. In this survey, twelve residential neighborhoods were selected to investigate the influence of SWSSs on the seasonal changes in heavy metal concentrations from input water to tank and tap water. The concentrations of nine evaluated heavy metals in all groups of water samples were found to be far below the specified standard levels in China. The concentrations of Fe, Mn, and Zn increased significantly from the input water samples to the tank and tap water samples in spring and summer (p < 0.05), especially for the water samples that had been stagnant for a long time. Negative correlations were found between most of the heavy metals and residual chlorine (Fe, Cu, Zn, and As, r = -0.186 to -0.519, p < 0.05). In particular, a high negative correlation was observed between Fe and residual chlorine (r = -0.489 to -0.519, p < 0.01) in spring and summer. Fe and Mn displayed positive correlations with turbidity (r = 0.672 and 0.328, respectively; p < 0.05). In addition, Cr and As were found to be positively associated with some nutrients (NO₃^-, TN, and SO₄^2-; r = 0.420-0.786, p < 0.01). The material of the storage tanks had little influence on the difference in heavy metal concentrations. Overall, this survey illustrated that SWSSs may pose a chronic threat to water quality and could provide useful information for practitioners.

Chemical Characterization and Non-targeted Analysis of Medical Device Extracts: A Review of Current Approaches, Gaps, and Emerging Practices

The developers of medical devices evaluate the biocompatibility of their device prior to FDA's review and subsequent introduction to the market. Chemical characterization, described in ISO 10993-18:2020, can generate information for toxicological risk assessment and is an alternative approach for addressing some biocompatibility end points (e.g., systemic toxicity, genotoxicity, carcinogenicity, reproductive/developmental toxicity) that can reduce the time and cost of testing and the need for animal testing. Additionally, chemical characterization can be used to determine whether modifications to the materials and manufacturing processes alter the chemistry of a patient-contacting device to an extent that could impact device safety. Extractables testing is one approach to chemical characterization that employs combinations of non-targeted analysis, non-targeted screening, and/or targeted analysis to establish the identities and quantities of the various chemical constituents that can be released from a device. Due to the difficulty in obtaining a priori information on all the constituents in finished devices, information generation strategies in the form of analytical chemistry testing are often used. Identified and quantified extractables are then assessed using toxicological risk assessment approaches to determine if reported quantities are sufficiently low to overcome the need for further chemical analysis, biological evaluation of select end points, or risk control. For extractables studies to be useful as a screening tool, comprehensive and reliable non-targeted methods are needed. Although non-targeted methods have been adopted by many laboratories, they are laboratory-specific and require expensive analytical instruments and advanced technical expertise to perform. In this Perspective, we describe the elements of extractables studies and provide an overview of the current practices, identified gaps, and emerging practices that may be adopted on a wider scale in the future. This Perspective is outlined according to the steps of an extractables study: information gathering, extraction, extract sample processing, system selection, qualification, quantification, and identification.

Fast and automated monitoring of gadolinium-based contrast agents in surface waters

Gadolinium-based contrast agents (GBCAs) are frequently used for magnetic resonance imaging to improve image contrast. These inert complexes are excreted unmetabolized from the human body and pass through wastewater treatment plants almost unaffected, leading to a significant release of anthropogenic Gd into the environment. However, long-term ecotoxicological effects of GBCAs are mainly unknown and thus powerful methods of speciation analysis are required to monitor their distribution and fate in aquatic systems. In this work, a rapid and efficient monitoring method was developed utilizing a fully automated single platform system for total metal analysis and syringe-driven chromatography in combination with inductively coupled plasma-mass spectrometry (ICP-MS). An anion-exchange chromatography (IC) method was developed and applied to achieve a rapid separation and sensitive detection of the five complexes Gd-HP-DO3A, Gd-BT-DO3A, Gd-DOTA, Gd-DTPA, and Gd-BOPTA that are commonly administered in the European Union. Furthermore, the use of an automated inline-dilution function allowed a fast-external calibration from single stock standards. A chromatographic run time of less than 2 min and species-specific detection limits between 11 and 19 pmol L^-1 on a quadrupole ICP-MS proved to be competitive compared to previously published methods, but without the use of aerosol desolvation and/or sector field ICP-MS to enhance sensitivity. The automated IC-ICP-MS method was applied for quantitative GBCA monitoring in a multitude of surface water samples that were obtained in the German state of North Rhine-Westphalia. The complexes Gd-HP-DO3A, Gd-BT-DO3A, and Gd-DOTA, were detected and quantified. In addition, the occurrence of an unidentified Gd species was observed for one of the sampled river systems.

A fast and automated separation and quantification method for bromine speciation analyzing bromide and 5-bromo-2'-deoxyuridine in enzymatically digested DNA samples via ion chromatography-inductively coupled plasma-mass spectrometry

A fast and automated separation and quantification method for bromide and the artificial nucleoside 5-bromo-2'-deoxyuridine (5-BrdU) via hyphenation of ion exchange chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS) is presented. The analysis of these two species is relevant to monitor the transfer of electrons along metal-mediated DNA base pairs. Charge transfer in DNA is of high interest for the implementation in nanotechnological applications like molecular wires. 5-BrdU as part of the DNA sequence releases bromide upon one electron reduction after efficient electron transfer along the DNA. The concentrations of 5-BrdU and bromide in enzymatically digested DNA samples can therefore be used as a marker for the efficiency of electron transfer along the DNA helix. A large number of samples was analyzed using an automated IC system. This platform enables time-efficient external calibration by inline dilution of a stock solution. Due to the fast separation of the two bromine species in less than 90 s, the developed method is suitable for screening applications with a multitude of samples. Despite the isobaric interferences and a low degree of ionization for bromine detection via ICP-MS the method has a limit of detection (LOD) of 30 ng/L which is approximately an order of magnitude lower than a comparable method using reversed phase high performance liquid chromatography (RP-HPLC) and ICP-MS.