Plasma Mass Spectrometry Method Research Articles

Determination of Iodine in Foods by Inductively Coupled Plasma Mass Spectrometry After Tetramethylammonium Hydroxide Extraction

In this study, the determination of iodine in 123 different types of foods was conducted. Iodine-selective electrode, microwave digestion/inductively coupled plasma mass spectrometry and tetramethylammonium hydroxide extraction/ inductively coupled plasma mass spectrometry (TMAH/ICP-MS) methods were tested to achieve the highest recoveries for the determination of iodine. Among them, TMAH/ICP-MS method was the most effective with respect to analytical recoveries (90–99%), limits of detection (0.013 µg/kg) and quantification (0.04 µg/kg) values. The intra- and inter-day relative standard deviations for iodine SRM were <4.8% and <10.8%, respectively. Iodine content in food samples showed a wide range of variations: 0.4–4 µg/100 g for fruits and vegetables, 4 µg/100 g for cereals and grain products, 15 µg/100 g for meat, 36 µg/100 g for milk, 137 µg/100 g for infant formula and 2.3–394 mg/100 g for seafood.

Mercury in samples of gas mixtures – a review of mercury sampling and determination methods

The determination of the composition of gas mixtures, especially those analytes which exist, for example, as contaminants for the main components of the gas mixture, very often requires the concentration of the analyte so that it can be quantified. The analysis of gaseous environmental samples, including air and air samples at workplaces, is difficult, which results from: the need to work with samples with an extensive matrix and heterogeneous distribution of pollutants, the stability of the analyte and the presence of interfering substances (interferents) in the sample. On the other hand, the analysis of trace components of gaseous fuels is difficult due to the need to collect a suitably concentrated sample so that these components can be quantified. This article provides an overview and analysis of the methods used for the collection and determination of mercury in gas mixtures. Currently, there are standardized mercury collection and determination methodologies dedicated to matrices such as air, workplace air, waste gases or natural gas. These are both manual and fully automated methods. Most of the methods described in the literature on the subject consist of two stages, i.e. the stage of collecting a sample for a solid or liquid sorbent and the stage of desorption and determination of the mercury content in the collected sample using methods dedicated to the analysis of this element. The most frequently used methods for collecting mercury samples in gas mixtures are: the gold amalgamation method and the sorption methods on powder sorbents (such as activated carbon, hopcalite, impregnated silica gel), glass fibers, impregnated cellulose filters and liquid sorbents (such as e.g. acids). The methods of sample desorption are varied and depend on the material on which the analyte has been absorbed and the selected mercury determination method. Three methods are mainly used to analyze samples for mercury content, i.e. the cold vapor atomic absorption spectrometry method (CV-AAS), the cold vapor fluorescence atomic spectrometry method (CV-AFS) and the inductively coupled plasma mass spectrometry method (ICP-MS). However, it should be kept in mind that although the methods available and used for the analysis of mercury content in gas are standardized, they are not resistant to the presence of hydrocarbons and hydrogen sulphide in the tested samples. These are the compounds that are most often mentioned as substances interfering in the determination of mercury in gases using the above-mentioned methods.

Personal exposure to PM2.5-bound heavy metals associated with cardiopulmonary function in general population.

To better understand the cardiopulmonary alterations associated with personal exposed PM2.5-bound heavy meals, we conducted a cross-sectional study in 2018 on 54 general residents. For each subject, PM2.5 exposure filter was collected by a low-volume sampler for 24h; blood and urine samples were collected subsequently. Heavy metals in PM2.5, blood, and urine samples were determined by inductively coupled plasma mass spectrometry method. PM2.5-bound Mn, Cd, Sb, Pb, and Ni levels were 20.5, 9.27, 9.59, 28.3, and 16.9ng/m3, respectively. The distribution of these metals followed the order: Pb (33.47%) > Mn (24.24%) > Ni (19.99%) > Sb (11.34%) > Cd (10.96%). The distribution of heavy meals in PM2.5, blood, and urine differed from each other. PM2.5-bound Cd, Pb levels were positively correlated with blood Cd, Pb levels (r= 0.323, r= 0.334, p< 0.05), respectively. PM2.5-bound Cd level was significantly higher in smoking group than non-smoking group (28.8 vs. 7.27ng/m3, p< 0.01), same as Sb level (12.0 vs. 9.34ng/m3, p< 0.01). Cd and Pb exposure might interact with cardiovascular function through autonomic regulation. No significant correlation was observed between metal exposure and pulmonary function. In conclusion, our data suggested that personal exposure to specific PM2.5-bound heavy metals might interact with profound cardiovascular alterations.

Pengaruh Media Perebusan Terhadap Komposisi Mineral Kerang Air Tawar Meti (Batissa violacea Lamarck, 1818)

This research aims were to analyzed mineral composition of fresh and processed meti freshwater mussels (Batissa violacea Lamarck,1818) and to know the effect of boiling media on the mineral composition with various added boiling media conditions that are water, NaCl 1%, and acetic acid 0.5%. Mineral compositions were tested with microwave digestion and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method. Mineral composition of fresh mussel were consisted of calcium (Ca) 10412 mg/kg, cobalt (Co) 0,182 mg/kg, copper (Cu) 3,54 mg/kg, magnesium (Mg) 345 mg/kg, mangan (Mn) 13,6 mg/kg, phosphor (P) 7753 mg/kg, potassium (K) 1163 mg/kg, sodium (Na) 291 mg/kg, and zinc (Zn) 44,2 mg/kg. The results of research on freshwater mussels in boiling media of water, NaCl 1%, and acetic acid 0.5% gave effect on the levels of minerals of calcium (Ca), magnesium (Mg), phosphor (P), potassium (K), sodium (Na ), cobalt (Co), copper (Cu), mangan (Mn) and there is no effect on the levels of zinc (Zn).

Simultaneous measurement of aqueous redox-sensitive elements and their species across the soil-water interface

The redox-sensitive elements, such as iron, manganese, sulfur, phosphorus, and arsenic, shift their speciation every millimeter (mm) across the soil-water interface in the flooded soil environments. Monitoring of element speciation at this high-resolution (HR) within the SWI is still difficult. The key challenge lies in obtaining sufficient porewater samples at specific locations along the soil gradient for downstream analysis. Here with an optimized inductively coupled plasma mass spectrometry (ICP-MS) method and a HR porewater sampler, we demonstrate mm-scale element profiles mapping across the SWI in paddy soils. High-concentrations of iron and manganese (> 10 mg/L) were measured by ICP-MS in an extended dynamic range mode to avoid signal overflow. The iron profile along the SWI generated by the ICP-MS method showed no significant difference (p < 0.05) compared to that measured independently using a colorimetric method. Furthermore, four arsenic (arsenite, arsenate, monomethylarsonic and dimethylarsinic acid), two phosphorus (phosphite and phosphate) and two sulfur (sulfide and sulfate) species were separated in 10 min by ion chromatography -ICP-MS with the NH4HCO3 mobile phase. We verified the technique using paddy soils collected from the field, and present the mm-scale profiles of iron, manganese, and arsenic, phosphorus, sulfur species (relative standard deviation < 8%). The technique developed in this study will significantly promote the measurement throughput in limited samples (e.g. 100 μL) collected by HR samplers, which would greatly facilitate redox-sensitive elements biogeochemical cycling in saturated soils.

A CE-ICP-MS/MS method for the determination of superparamagnetic iron oxide nanoparticles under simulated physiological conditions

Over the past few years, superparamagnetic iron oxide nanoparticles (SPIONs) have attracted much attention due to their medicinally attractive properties and their possible application in cancer diagnosis and therapy. However, there is still a lack of appropriate methods to enable quantitative monitoring of the particle changes in a physiological environment, which could be beneficial for evaluating their in vitro and in vivo behavior. For this reason, the main goal of this study was the development of a novel capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS/MS) method for the determination of SPIONs suitable for the future examination of their changes upon incubation with proteins under simulated physiological conditions. The type and flow rate of the collision/reaction gas were chosen with the aim of simultaneous monitoring of Fe and S. The type and concentration of the background electrolyte, applied voltage, and sample loading were optimized to obtain SPION signals of the highest intensity and minimum half-width of the peak. Analytical parameters were at a satisfactory level: reproducibility (intra- and inter-day) of migration times and peak areas (presented as RSD) in the range of 0.23–4.98%, recovery: 96.7% and 93.3%, the limit of detection (for monitoring 56Fe16O+ by mass-shift approach) 54 ng mL−1 Fe (0.97 μM) and 101 ng mL−1 Fe (1.82 μM) for SPIONs with carboxyl and amino terminal groups, respectively. To the best of our knowledge, this is the first reported use of CE-ICP-MS/MS for the quantification of SPIONs and monitoring of interactions with proteins.

Comparison of two methods for the assessment of intra-erythrocyte magnesium and its determinants: Results from the LifeLines cohort study

BackgroundDirect methods for the assessment of intra-erythrocyte magnesium (dIEM) require extensive sample preparation, making them labor intensive. An alternative, less labor intensive method is indirect calculation of intra-erythrocyte magnesium (iIEM). We compared dIEM and iIEM and studied determinants of dIEM and iIEM, plasma magnesium and 24-h urinary magnesium excretion in a large population-based cohort study. MethodsdIEM and iIEM were measured using a validated inductively coupled plasma mass spectrometry (ICP-MS) method in 1669 individuals from the second screening from the LifeLines Cohort Study. We used linear regression analyses to study the determinants of IEM, plasma magnesium and 24-h urinary magnesium excretion. ResultsMean dIEM and iIEM were 0.20 ± 0.04 mmol/1012 cells and 0.25 ± 0.04 mmol/1012 cells, respectively. We found a strong correlation between dIEM and iIEM (r = 0.75). Passing-Bablok regression analyses showed an intercept of 0.015 (95% CI: 0.005; 0.023) and a slope of 1.157 (95% CI: 1.109; 1.210). In linear regression analyses, plasma levels of total- and LDL -cholesterol, and triglycerides were positively associated dIEM, iIEM, and plasma magnesium, while glucose and HbA1c were inversely associated with plasma magnesium. ConclusionsWe observed a strong correlation between dIEM and iIEM, suggesting that iIEM is a reliable alternative for the labor intensive dIEM method.

Arsenic and Lead Determination in D&C Red No. 6 Lakes and D&C Red No. 7 Lakes Containing Barium Sulfate Using X-Ray Fluorescence Spectrometry.

Color additives requiring batch certification by the U.S. Food and Drug Administration have Code of Federal Regulations (CFR) specification limits for certain elements and are usually analyzed by x-ray fluorescence spectrometry (XRF). However, analysis of some color additives presents difficulties. An XRF method was developed for quickly determining whether barium sulfate-containing color additives certifiable as D&C Red No. 6 lakes and D&C Red No. 7 lakes meet the CFR specifications for arsenic (As) and lead (Pb). Difficulties in preparing XRF standards and analyzing As and Pb in matrices with the heavy x-ray absorber barium (Ba) were overcome by first preparing As- and Pb-fortified cellulose, then blending color additive samples with fortified and unfortified cellulose to produce XRF calibration materials. Satisfactory compensation for changes in intensity caused by Ba absorption was achieved by measuring varying concentrations of As and Pb at several concentrations of Ba. Test samples of barium sulfate-containing D&C Red No. 6 lakes and D&C Red No. 7 lakes were analyzed by the XRF method and by an inductively coupled plasma-mass spectrometry (ICP-MS) method. The ICP-MS method poses some difficulties and is time consuming. In contrast, the XRF method requires very little sample preparation, is nondestructive, uses calibrations that are stable for long periods of time, and offers acceptable determination limits (1 mg/kg As, 4 mg/kg Pb) which are less than the CFR specification limits (3 mg/kg As, 20 mg/kg Pb). The new XRF method is applicable for use in routine batch certification.

Application of μ-TLC for speciation of inorganic arsenic by laser ablation inductively coupled plasma mass spectrometry

A novel µ-Thin layer Chromatography coupled with Laser Ablation Inductively coupled Plasma Mass Spectrometry method based on Ion Imprinted Polymer (IIP) is developed for the first time in this paper which tries to investigate the separation of inorganic arsenic species in aqueous media. Surface morphology, functionality, and bulk composition of the as-synthesized copolymer were confirmed utilizing multiple techniques, such as XRD, FESEM, and FT-IR. IIP-Copolymer was combined with CaSO4, as a binder agent, that was used to prepare a thin layer chromatography plate. Subsequently, inorganic arsenic species were separated over the TLC plate based on As(V)-imprinted polymer. In the following, the plate surface was scanned via laser ablation which volatilized the inorganic arsenic species from the TLC plate and then introduced them to the ICP-MS system. The effect of some experimental conditions including pH, mobile phase composition, and IIP/CaSO4 mass ratio on the separation efficiency were also investigated. Moreover, the obtained results for the spiked inorganic arsenic species in real samples, such as Angouran, Nakhlak, and Zarshouran proved that the methods were practically applicable to speciation analysis. Under the established optimal condition, the detection limit, Relative Standard Deviation (RSD) of responses, and linear dynamic range (LDR) of the method were obtained as 0.3 μg L−1, 3.8%, and 0.2–100 μg L−1 for As(V) assay. The IIP-µTLC/LA-ICP-MS has also illustrated great application perspectives for rapid and high-effective selection, characterization, and separation of ultra-trace inorganic arsenic species in environmental water samples.

Sensitive and selective detection of Hg2+ in tap and canal water via self-enhanced ECL aptasensor based on NH2–Ru@SiO2-NGQDs

In the present study, a novel self-enhanced electrochemiluminescence (ECL) aptasensor which combined self-enhanced ECL composite as signal response element and aptamer as the specific recognition element was firstly proposed for the sensitive and selective detection of Hg2+. Innovatively, the luminophore Ru(bpy)32+-doped silica nanoparticles functionalized with 3-aminopropyltriethoxysilane (NH2–Ru@SiO2) and the co-reactant nitrogen doped graphene quantum dots (NGQDs) were bound together to form the self-enhanced ECL composite, NH2–Ru@SiO2-NGQDs, by electrostatic adsorption. Satisfactorily, high and stable luminous efficiency of NH2–Ru@SiO2-NGQDs was obtained benefited from the short electron transfer distance and low energy loss of self-enhanced-typal ECL composite. For the fabrication of the self-enhanced ECL aptasensor for Hg2+ detection, the Hg2+ aptamer, of which one end was connected to NH2–Ru@SiO2-NGQDs, and the other end was fixed on glass carbon electrode (GCE) surface through Au–S bond, was served as a bridge. Upon the addition of Hg2+, the aptamer was bent due to the formation of thymine-Hg2+-thymine (T-Hg2+-T) specific structure, which caused the self-enhanced ECL composite was close to the GCE surface. On this basis, a linearly enhanced ECL signal was acquired with the concentration of Hg2+ in the range of 5.0 × 10−11 M − 1.0 × 10−6 M with excellent selectivity, repeatability and stability in 3 min for each assay. In addition, the proposed aptasensor showed satisfying accuracy and practicability for Hg2+ analysis in tap and canal water verified by the inductively coupled plasma-mass spectrometry (ICP-MS) method.

Food Fingerprinting: Using a Two-Tiered approach to Monitor and Mitigate Food Fraud in Rice.

Rice is an important staple food that is consumed around the world. Like many foods, the price of rice varies considerably, from very inexpensive for a low-quality product to premium pricing for highly prized varieties from specific locations. Therefore, like other foods it is vulnerable to economically motivated adulteration through substitution or misrepresentation of inferior-quality rice for more expensive varieties. In this article we describe results of a research project focused on addressing potential food fraud issues related to rice supplies in China, India, Vietnam, and Ghana. Rice fraud manifests differently in each country; therefore, tailored solutions were required. Here we describe a two-tiered testing regime of rapid screening using portable Near Infrared technology supported by second tier testing using mass spectrometry-based analysis of suspicious samples. Portable Near Infrared spectroscopy models and laboratory-based Gas Chromatography-Mass Spectrometry methods were developed to differentiate between: high-value Basmati rice varieties and their potential adulterants; six Geographic Indicated protected rice varieties from specific regions within China; various qualities of rice in Ghana and Vietnam; and locally produced and imported rice in Ghana. Furthermore, an Inductively Coupled Plasma-Mass Spectrometry method was developed to support the Chinese rice varieties methods as well as a Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry method for quality differentiation in Vietnam. This two-tier approach can provide a substantially increased level of testing through rapid screening outside of the laboratory with the reassurance of corroborating mass spectrometry-based laboratory analysis to support decision making.

Influence of sample surface topography on laser ablation process

In this work we discuss how sample surface topography can significantly influence the laser ablation (LA) process and, in turn, the analytical response of the LA Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) method. Six different surface topographies were prepared on a certified aluminium alloy sample BAM 311 and SRM NIST 610 to investigate the phenomenon. All the samples were repetitively measured by LA-ICP-MS using a spot by spot analysis. The effect of laser fluence in the range of 1–13 J/cm2 was studied. For majority of measured isotopes, the ICP-MS signal was amplified with roughening of the sample surface. A stronger effect was observed on the Al alloy sample, where the more than sixty-time enhancement was achieved in comparison to the polished surface of the sample. Since the effect of surface topography is different for each analyte, it can be stated that surface properties affect not only the ICP-MS response, but also elemental fractionation in LA. The presented results show that different surface topographies may lead to misleading data interpretation because even when applying ablation preshots, the signal of individual elements changes. The utmost care must be taken when preparing the surface for single shot analysis or chemical mapping. On the other hand, by roughening the sample surface, it is possible to significantly increase the sensitivity of the method for individual analytes and supress a matrix effect.

Assessment of potentially harmful elements in floodplain soils and stream sediments in Ile-Ife area, South-western Nigeria

The enrichment of potentially harmful elements (PHEs) in stream sediments (SS) and floodplain soils (FS) poses great environmental hazards to water bodies and other parts of the ecosystem. The aim of this research was to evaluate the distribution pattern of selected PHEs (Cu, Pb, Zn, Co, Mn, As, Cd, V, Cr, Ni, Th, Sr and La) in SS of selected rivers that drain Ile-Ife area and their adjacent FS, to ascertain the pollution status of these elements in the study area. Sixty samples (40 SS and 20 FS) were purposely collected for this study; the samples were analysed with ultra-trace inductively coupled plasma mass spectrometry method (ICP-MS). The PHEs results showed decreasing trend of average contents of PHEs studied; Mn > Zn > V > Cr > Pb > La > Sr > Cu > Ni > Co > Th > As > Cd for both SS and FS. Also, PHEs concentration in the studied geo media showed a significant level of enrichment as observed from the results. Elemental association showed positive correlation for topsoil, Pb/Zn = R2, 0.85 and negative correlation for topsoil Cr/Zn = R2 0.02 among the other PHEs. Source apportionment showed that the studied metal enrichment is largely anthropogenic rather than geogenic. Geoaccumulation and metal ratio indexes indicated that FS and SS studied have received significant PHEs of between moderately to strongly polluted, which implies significant environmental implications in the study area.

Higher toenail selenium is associated with increased insulin resistance risk in omnivores, but not in vegetarians

BackgroundThe relationship between selenium (Se) and insulin resistance remains unclear. We aim to explore the association between toenail Se levels and insulin resistance through a cross-sectional study comprising Chinese vegetarians and matched omnivores.MethodsIn this study, we enrolled 220 vegetarians and 220 omnivores matched by age and sex from Shanghai. The inductively coupled plasma mass spectrometry method was used to measure toenail Se levels. Dietary Se intakes were assessed by the 24-h dietary recall method. Blood samples were collected to measure fasting blood glucose level and fasting insulin concentrations. Insulin resistance index (HOMA-IR) and insulin secretion index (HOMA-B) were calculated to evaluate insulin resistance. Multi-linear regression analysis was performed to determine the association between toenail Se levels and insulin resistance, after adjusting for confounders.ResultsThe mean ages of vegetarians (76 vegans, 144 lacto-ovo-vegetarians) and omnivores were 35.96 ± 8.73 years and 35.23 ± 8.93 years, respectively. Of these, 180 (81.8%) were female and 40 (18.2%) were male. No association was found between toenail Se levels and insulin resistance in vegetarians. However, the concentration of Se in toenails was positively correlated with fasting insulin levels (β = 1.030, 95%CI: 0.393 to 1.667) and HOMA-IR (β = 0.245, 95%CI: 0.098 to 0.392) in omnivores, after multivariate adjustment for age, sex, BMI, alcohol consumption, income, and daily dietary intakes (energy, protein, fat, carbohydrate, and fiber). This positive relationship persisted only in omnivores whose dietary Se intake was above 60 μg/d.ConclusionsHigher toenail Se levels were associated with increased insulin resistance risk in Chinese omnivores whose dietary Se intake was above 60 μg/d, but not in vegetarians. These findings create awareness on the association of dietary Se intake above 60 μg/d with the risk of insulin resistance.

Monitoring of toxic heavy metals contamination in commonly used Chinese materia medica

Monitoring of toxic heavy metals (THMs) contamination, including lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg), for the quality control in Chinese materia medica (CMM) is critical for ensuring safe medication use in the pharmaceutical industry. A validated inductively coupled plasma–mass spectrometry method was used to determine THMs content in 1887 samples for 27 selected types of commonly used CMM. The correlation coefficient of the calibration curves for four THMs was higher than 0.995, indicating that the linearity is fine. The recovery rate was ranged in 82.6–105.4% for four THMs. The percentage of RSD in inter-day and intra-day precision test for four THMs was all lower than 10%. The limit of quantitation in test solution for Pb, As, Cd and Hg was 0.212, 0.500, 0.038, 0.044 μg/L, indicating that this validated ICP-MS method exhibited excellent sensitivity. Among these THMs, Pb and Cd are the most abundant contaminants in 27 selected types of CMM. In diverse permissible limits (PL) established by different countries/organizations, Cinnamomi ramulus and Eucommiae cortex usually exceeded the PL of 0.3 μg/g for Cd and occasionally exceeded the PL of 5.0 μg/g for Pb. Chuanxiong rhizome seldom exceeded the PL of 1.0 μg/g for Cd. Eucommiae cortex, Raphani semen, Atractylodis macrocephalae rhizoma and Bupleuri radix occasionally exceeded the PL of 0.3 μg/g for Cd. In conclusion, we hope to raise awareness of THMs contamination in commonly used CMM that affects safe medication use among farmers, manufacturer, and consumers.

Ion chromatography as candidate reference method for the determination of chloride in human serum.

BackgroundWe developed an ion chromatography (IC) method for measurement of chloride in human serum which was regarded as a simple, rapid, accurate, and sensitive technique. The method will be hopefully selected as a candidate reference method.MethodSerum aliquots of 0.1 mL were diluted 500 times with Milli‐Q water, and chloride in serum samples was measured by IC with a gradient elution procedure using a KOH eluent generator.ResultsBased on the data, chloride in human serum was well detected by IC. The calibration curve for chloride was linear in the concentration range from 0 to 0.42 mmol/L with a correlation coefficient of .99995 under the optimum experimental conditions. The chloride concentration had a good linear relationship with the peak areas of chloride. This method was sensitive because of the low limit of detection (LOD) and the low limit of quantification (LOQ) 9.87 × 10−5 mmol/L and 3.27 × 10−4 mmol/L, respectively. Besides, the method was highly precise with the within‐run coefficient of variations (CVs) for the measurement of low, medium, and high concentration level samples 0.32%, 0.73%, and 0.50%. As for the evaluation of accuracy, the biases were less than ±1% and 2% by comparing with National Institute of Science and Technology (NIST) standard material SRM 956d and 2013‐2018 IFCC‐RELA samples, respectively. Finally, the biases between IC method and the inductively coupled plasma mass spectrometry (ICP‐MS) method were less than 1% which showed good agreement.ConclusionIon chromatography is a simple sample treatment procedure for the determination of chloride in human serum with high sensitivity and specificity. The proposed method could be recommended as a candidate reference method for the determination of serum chloride in human serum.

Sweat chloride assay by inductively coupled plasma mass spectrometry: a confirmation test for cystic fibrosis diagnosis

The current guidelines for sweat chloride analysis identify the procedures for sweat collection, but not for chloride assay, which is usually performed by methods originally not aiming at the low concentrations of chloride found in sweat. To overcome this limitation, we set up, characterized, and adopted an original inductively coupled plasma mass spectrometry (ICP-MS) method for sweat chloride determination, which was designed for its easy use in a clinical laboratory. The method was linear in the range 8.5E−3 to 272.0E−3 mM, precision exhibited a relative standard deviation < 6%, and accuracy was in the range 99.7–103.8%. Limit of blank, limit of detection, and limit of quantitation were 2.1 mM, 3.2 mM, and 7.0 mM, respectively, which correspond to real concentrations injected into the mass spectrometer of 3.9E−3 mM for LOD and 8.5E−3 mM for LOQ. At first, the method was tested on 50 healthy volunteers who exhibited a mean chloride concentration of 15.7 mM (25–75th percentile 10.1–19.3 mM, range 2.8–37.4 mM); then, it was used to investigate two patients with suspected cystic fibrosis, who exhibited sweat chloride values of 65.6 mM and 81.2 mM, respectively. Moreover, the method was cross-validated by assaying 50 samples with chloride concentration values in the range 10–131 mM, by both ICP-MS and coulometric titration, which is the technology officially used in Tuscany for cystic fibrosis newborn screening. The reference analytical performances and the relatively low cost of ICP-MS, accompanied by the advantageous cost of a single sweat chloride assay, make this technology the best candidate to provide a top reference method for the quantification of chloride in sweat. The method that we propose was optimized and validated for sweat samples ≥ 75 mg, which is the minimum amount requested by the international protocols. However, the method sensitivity and, in addition, the possibility to reduce the sample dilution factor, make possible the quantification of chloride even in samples weighting < 75 mg that are discarded according to the current guidelines.Graphical abstract

Doping control analysis of total arsenic in equine plasma.

Arsenic can be easily found in our surrounding environment. Because of its ubiquitous nature, horse urine and blood invariably contain low levels of arsenic. Nevertheless, inorganic arsenic, despite its general use as a tonic for horses, is an effective doping agent having a deleterious effect because of its ability to induce gastroenteritis. The misuse of arsenic in horseracing has been controlled by an international urinary threshold of total arsenic at 0.3 μg/mL. However, an equivalent threshold for total arsenic in plasma is yet to be established. In this study, an inductively coupled plasma-mass spectrometry method has been developed for quantifying total arsenic in equine plasma. Statistical analysis determined that the data from a population study of 1,552 post-race and out-of-competition plasma samples fits a Gaussian mixture model with two Gaussian components. A rounded-up provisional threshold for plasma total arsenic at 2.5 ng/mL was subsequently established. Results from administration trials with a sodium arsanilate-containing supplement showed that both urinary and plasma arsenic was significantly elevated after administration. The maximum urinary detection time was around 22 h based on the international threshold. However, the maximum plasma detection time would be longer than 73 h if the provisional threshold of 2.5 ng/mL was adopted. In view of the high discrepancy between the urine and plasma detection times, a revised plasma threshold of 15 ng/mL is proposed to afford a comparable detection time in both matrices. The risk of a normal sample exceeding the proposed plasma total arsenic threshold is practically zero.

Health Risk Evaluation of Trace Elements in Geophagic Kaolinitic Clays within Eastern Dahomey and Niger Delta Basins, Nigeria.

The deliberate consumption of earthly materials is a universally recognised habit with health benefits and risks to those that practice it. Thirteen (13) samples comprising of six (6) Cretaceous and seven (7) Paleogene/Neogene geophagic kaolinitic materials, respectively, were collected and analysed for trace element concentrations (V, Cr, Co, Ni, Zn, Pb, and Fe), and possible risk on consumers’ health. The trace element compositions were obtained using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and X-ray fluorescence spectrometry (XRF) analytical methods. Based on their average concentrations, Fe > V > Cr > Ni > Zn > Pb > Cu > Co and Fe > V > Cr > Zn > Cu > Pb > Ni > Co for the Cretaceous and Paleogene/Neogene geophagic clays, respectively. Iron concentrations were significantly higher in Paleogene/Neogene geophagic clays than in Cretaceous geophagic clays. The nutritional value of Cu and Zn were lower whereas, Cr and Fe were higher than the recommended dietary intake. The index of geoaccumulation (0 < Igeo ≤ 1) showed that the geophagic materials were uncontaminated to moderately contaminated by the trace elements. The overall hazard indices (HI) for non-carcinogenic effects showed that the geophagic clays pose threat to children (HI > 1) and no threat to adults (HI < 1) health. However, the carcinogenic risk indices (CRI) for Cr, Ni, and Pb were within acceptable cancer risks (10−6 < CRI < 10−4) for children and adults. Hence, based on the trace element s HI and CRI, this study concluded that the consumption of Cretaceous and Paleogene/Neogene geophagic kaolinitic clays poses no risks to adult health but children might suffer health risk if the geophagic clays are not beneficiated before ingestion.

Consequences of Iodine Deficiency and Excess in Pregnancy and Neonatal Outcomes: A Prospective Cohort Study in Rio de Janeiro, Brazil.

Background: Insufficient or excessive iodine intake during gestation may compromise adaptive mechanisms in maternal thyroid function and lead to adverse pregnancy outcomes. In this context, we aimed to study the effects of maternal iodine status in the first and third trimesters of gestation on obstetric and neonatal outcomes in an iodine-sufficient population in Rio de Janeiro, Brazil. Methods: A total of 214 pregnant women in the first trimester of gestation were enrolled and prospectively followed until delivery between 2014 and 2017. All participants were ≥18 and ≤35 years, had a spontaneous single pregnancy, and had no history of thyroid or other chronic diseases, nor were they taking iodine-containing supplements at enrollment. In the first trimester, we obtained clinical information and determined thyroid function and the urinary iodine concentration (UIC) of the participants. Thyroid function and UIC were reassessed in the third trimester. Iodine status was determined by the median of UIC obtained from six urine spot samples by the inductively coupled plasma mass spectrometry method. Pregnancy and neonatal outcomes and delivery information were obtained from medical records. Results: The median UIC in the whole population was 219.7 μg/L. The prevalence of UIC <150 μg/L was 17.2%, and 38.7% had UIC ≥250 μg/L. Gestational diabetes (GDM) was higher in the group with UIC 250-499 μg/L (n = 77) compared with the group with UIC 150-249 μg/L (n = 94) (20.3% vs. 9.7%, p < 0.05). Ultimately, UIC ≥250 μg/L was an independent risk factors for GDM (relative risk [RR] = 2.9 [confidence interval, CI = 1.1-7.46], p = 0.027) and hypertensive disorders of pregnancy (HDP) (RR = 4.6 [CI = 1.1-18.0], p = 0.029). Among 196 live-born newborns, lower birth length was observed in infants whose mothers had UIC <150μg/L (n = 37) in the first trimester compared with those with UIC 150-249 μg/L (n = 86) (median interquartile range: 48.0 [2.2] vs. 49.0 [4.0] cm, p = 0.01). Maternal UIC <150 μg/L was negatively associated with birth length of newborns (Exp (B) = 0.33 [CI = 0.1-0.9], p = 0.03). Conclusions: In a population whose median iodine intake is sufficient, extensive individual variation occurs. Such abnormalities are associated with increased GDM and HDP when UIC is ≥250 μg/L, and lower infant birth length when UIC is <150 μg/L.