Standard Addition Calibration Research Articles

Comparison and application of the extraction methods for the determination of pharmaceuticals in water and sediment samples

Due to increasing consumption and production, pharmaceuticals are omnipresent in the environment. Regardless of whether they are present in low concentrations, their detection in the environment is of great concern for human health. Due to the appearance of new pharmaceuticals on the market, there is always a need to develop new analytical methods to determine their presence in various environmental samples. So, in this paper, new LC-MS/MS method was developed for the determination of 13 pharmaceuticals (azithromycin, tiamulin, imatinib, febantel, torasemide, omeprazole, linezolid, praziquantel, etodolac, sulfamethazine, sulfafurazole, albendazole, levamisole) in water and sediments samples.Pharmaceuticals were isolated from water by solid-phase (SPE) and stir-bar sorptive extraction (SBSE), while extracts from sediment samples were obtained by matrix-solid phase dispersion (MSPD) and ultrasound-assisted extraction (UAE). After optimization of extraction conditions, the methods were validated in terms of linearity, LOQ, LOD, precision, recovery and matrix effect. The LOQ of the optimized method were 2.5 ng/L-0.5 µg/L for SPE extraction and 0.1–10 µg/L for SBSE extraction from water, and 2.5 ng/g-25 μg/g for MSPD extraction and 0.025 do 5 µg/g for UAE extraction from sediment depending on the pharmaceuticals. Recoveries were matrix dependent (20–150 %), particularly for SBSE extraction and at the lowest investigated concentration tested, so standard addition calibrations were required for quantification in real samples. The standard addition calibration lines showed high linearity (R2 > 0.97) and replicate extractions showed good reproducibility (RSD≤%).Results obtained show that SPE is much more sensitive than SBSE, while for extraction from sediments both methods are equally sensitive, whereas for some tested pharmaceuticals MSPD is better and for others UAE is better. By comparing the sample preparation methods used, attention is drawn to the fact that, despite the large number of possible methods, not all of them are always equally good with regard to the target components and the type of sample.

OLIVE PITS-BASED CARBON BLACK AGGLOMERATE AS AN ADSORBENT FOR PIPETTE-TIP SOLID-PHASE EXTRACTION FOR THE DETERMINATION OF CAFFEINE IN ENERGY DRINKS

Vegetal wastes are an interesting source for the synthesis of nanostructured carbon materials, which are potentially useful in various applications. Carbon black agglomerates (CBA) obtained from olive pits, synthesized in our previous research, had a low crystalline structure typical of this type of materials, with a pore size of 2.27 nm, confirming their micro/mesoporous structure, and with a high surface value of around 587 m2/g. These materials were used for the extraction of caffeine in energy drinks using a green-approach micro-sample technique called pipette-tip solid-phase extraction. This microextraction technique features reduced consumption of organic solvents, of the amount of sorbent and extraction time, thus making the whole sample pretreatment process faster and greener. In this work, we proposed an analytical method for the analysis of caffeine in commercial energy drinks, using CBA with a great extraction capacity due to its high porous surface area. The developed methodology has proven to be useful from a green chemistry point of view, using only one milligram of nanostructured sorbent, minimal solvent consumption, a reduced volume of sample, as well as easy and rapid automatization for the analysis of commercial energy drinks. For the quantification of the analyte in the energy drinks, a one-point standard addition calibration was applied to correct the matrix effect. Similar caffeine concentrations per milliliter were found in the three analyzed samples, likewise, the amounts of caffeine close to those reported by the manufacturers were established for two of the samples analyzed.

Chemical Standardization of Milk Thistle (Silybum marianum L.) Extract Using UHPLC-MS/MS and the Method of Standard Addition.

Extracts prepared from the seeds of the medicinal plant milk thistle [Silybum marianum (L.) Gaertn. (Asteraceae)] are widely used as dietary supplements due to anti-inflammatory, antitumor, and hepatoprotective effects. Called silymarin, the main components of lipophilic extracts of milk thistle seeds are flavonoids and flavonolignans including silybin A, silybin B, isosilybin A, isosilybin B, silydianin, silychristin, taxifolin, and 2,3-dehydrosilybins. The aim of this study was to develop a method based on UHPLC-MS/MS for the chemical authentication and standardization of milk thistle silymarin. Validation included the method of standard addition to account for the lack of a blank matrix. Potential matrix effects were investigated by analyzing silymarin standards dissolved only in the initial UHPLC mobile phase. Measurements of six flavonolignans and taxifolin in the milk thistle extract using UHPLC-MS/MS with standard addition or external standard calibration produced similar results for all analytes except silydianin and 2,3-dehydrosilybin B, which showed significant peak enhancement during negative ion electrospray due to botanical matrix effects. The UHPLC-MS/MS-based method of standard addition requires <10 min per injection and is suitable for the standardization of silymarin from milk thistle in support of preclinical and clinical studies of safety and efficacy.

Quantification of linear alkylbenzene sulphonates in complex sludge samples: Influence of matrix effects in calibration methods

Linear Alkylbenzene Sulfonates (LAS) are among the priority organic pollutants in sludge owing to their high concentrations, due to its use as a major cleaning agent (surfactant) in laundry detergents and household cleaning products, and to the concentration limits of 2,600 mg/kg outlined in the EU directive draft for land application of sludge. In this work, a method has been optimized and validated for the accurate quantification of LAS homologues C10-C13 in different types of samples in the sludge treatment and disposal process including primary, secondary, and digested sludge, compost, and soil. The type of matrix had a significant impact on the method’s validation process, resulting in the need of the use of distinct dilution factors for each matrix. Overall, the procedure propose involves a cost-effective and user-friendly technique that combines both extraction and clean-up in a single step (ultrasound-assisted extraction and dispersive solid phase extraction). Analytical determination is conducted using liquid chromatography-tandem mass spectrometry. The method demonstrated excellent accuracy (relative recoveries exceeding 84.5 % across all types of sludge samples) and the limit of quantification enables the measurement of LAS concentrations up to 1000 times lower than the concentration limits stipulated in the EU directive draft. For an accurate quantification, three calibration approaches were tested (external calibration, standard addition, and matrix-matched calibration). Standard addition was the preferred method for quantitative analysis. It helps mitigate matrix effects that could otherwise distort the accuracy of analyte measurements, making it crucial for quality control, especially in monitoring applications where matrix effects may introduce bias into concentration calculations.

Unlocking the electrochemical signature of Naringenin: Implications for screening in pharmaceutical formulations

Naringenin (NAR) is a versatile herbal flavonoid known for its broad pharmacological benefits, including antioxidant, anti-inflammatory, and anticancer properties. These properties underscore its potential and necessity for industrial applications within the pharmaceutical sector, making its detection and quantification crucial for ensuring the quality and efficacy of pharmaceutical products. Addressing the imperative for a sensitive and sustainable screening approach, this research leverages electrochemical analysis techniques including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). Complementary to experimental investigations, the electronic structure of NAR was probed using B3LYP/Def2-TZVPPD calculations alongside Fukui and dual descriptor analyses. Our findings delineate the dissociation kinetics of the hydroxyl groups within NAR, with particular emphasis on the phenolic group’s proton as the primary dissociation site, elucidating pivotal insights into the oxidation mechanism of NAR. Noteworthy is the irreversibility of the electrochemical oxidation process observed on both non-modified glassy carbon electrode (GCE) and gold electrode (GE), indicating a one-electron-one-proton mechanism. Utilizing the external calibration method and GCE, a linear range from 1.36 to 19.1 mg L-1 in Britton-Robinson (BR) supporting electrolyte was established, exhibiting a limit of detection (LOD) of 0.11 mg L-1 (R2 = 0.9945). For GE, the standard addition calibration approach revealed one linear range, from 0.27 to 0.48 mg L-1 (LOD of 0.04 mg L-1, R2 = 0.9960). Importantly, the proposed methodologies demonstrate satisfactory selectivity against potential interferences, with intra- and inter-day precision exhibiting low relative standard deviation (RSD) values. This study introduces a simple, sensitive, stable, selective, and sustainable electroanalytical method for the detection of NAR in pharmaceutical formulations, harnessing the advantages of unmodified electrodes and rigorous experimental validation.

Matrix overcompensation calibration: A new strategy to correct matrix effects of carbon origin in multielement analysis by inductively coupled plasma mass spectrometry

BackgroundElemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) may suffer from matrix effects; those caused by organic matrices cannot be corrected by internal standardization. A new strategy, matrix overcompensation calibration (MOC), was developed to correct such matrix effects. ResultsClear fruit juices were diluted 1:50 in 1 % HNO3 (v/v)- 0.5 % HCl (v/v)- 5 % ethanol (v/v). A standard series was treated likewise to construct an external calibration curve. As, Se, Cd, and Pb in juices were determined by dilute-and-shoot ICP-MS based on this MOC strategy. The results agreed with those obtained by standard addition calibration and microwave-aided digestion; data accuracy was validated by spike-recovery studies. SignificanceUnlike standard addition calibration, a single external calibration curve established by MOC can be applicable to juices of diversified fruit, geographical, and manufacturer origins enhancing productivity.

Simple and accurate on-site quantitation of BTEX in atmospheric air using solid-phase microextraction and gas chromatography with photoionization detection

This paper represents an improved method for on-site quantitation of benzene, toluene, ethylbenzene, and xylenes (BTEX) in atmospheric air using solid-phase microextraction (SPME) and portable gas chromatography with a split/splitless inlet and photoionization detector (GC-PID). The developed method includes air pumping to four replicate 250 mL gas sampling bulbs, three of which are extracted by 85 µm Carboxen/polydimethylsiloxane (Car/PDMS) coating at 40°C, while the last one is spiked with BTEX standard in nitrogen and extracted under the same conditions. Compared to other similar SPME-based methods, the developed method does not require a standard gas generator and traceable certified permeation tubes for instrument calibration.The method was applied for on-site BTEX quantitation in air of Talgar, Almaty oblast, Kazakhstan in February and March 2024, at two different extraction times, among which 15 min was chosen as optimal because it provided sufficient detection limits of ethylbenzene, and xylenes. The on-site standard addition calibration allowed accurate BTEX quantitation. In February, only benzene (18.3 and 6.8 µg/m3) and toluene (15.7 and 8.5 µg/m3) were detected. In March samples, concentrations of benzene were 12.3 and 7.4 µg/m3, toluene - 23 and 5.4 µg/m3, ethylbenzene – 5.5 µg/m3 and not detected, m-/p-xylene - 3.6 and 2.1 µg/m3, o-xylene - 6.8 and 10.6 µg/m3. The LODs for benzene, toluene, ethylbenzene, m-/p-xylene, and o-xylene were 0.07, 0.3, 2, 0.8 and 2 µg/m3, respectively. The developed method can be recommended for quick and low-cost on-site quantification of BTEX in atmospheric air, particularly at remote locations.

Evaluation of Aeris mid-infrared absorption (MIRA), Picarro CRDS (cavity ring-down spectroscopy) G2307, and dinitrophenylhydrazine (DNPH)-based sampling for long-term formaldehyde monitoring efforts

Abstract. Current formaldehyde (HCHO) measurement networks rely on the TO-11A offline chemical derivatization technique, which can be resource intensive and limited in temporal resolution. In this work, we evaluate the field performance of three new commercial instruments for continuous in situ formaldehyde monitoring: the Picarro cavity ring-down spectroscopy G2307 gas concentration analyzer and Aeris Technologies' mid-infrared absorption Pico and Ultra gas analyzers. All instruments require regular drift correction, which is accomplished through instrument zeroing using dinitrophenylhydrazine (DNPH)-coated cartridges, Drierite, or molecular sieves, while heated Hopcalite failed to remove all incoming HCHO. We show that a modified precision estimate accounting for regular instrument zeroing results in values of 0.09, 0.20, and 0.22 ppb at a 20 min integration time for the G2307, Ultra, and Pico, respectively. After applying standard addition and dynamic dilution calibrations, all instruments agreed within 13 % and were well correlated with each other (all r ≥ 0.90). TO-11A HCHO observations resulted in a normalized mean bias of −58 % compared to co-located Picarro G2307 measurements (r=0.62, slope = 0.38, int = 0.07 ppb HCHO). Using a 6-month deployment period in the Atlanta metropolitan area, we determined that the Picarro G2307 and Aeris units have sufficient accuracy and precision to capture the Atlanta spatial HCHO gradient. We find that midday HCHO concentrations have decreased by 22.3 % since 1999 in the city's urban core, and DNPH measurements at a nearby Photochemical Assessment Monitoring Station (PAMS) site show a greater decrease of 53 %.

Determination of nitrofuran metabolites in muscle by LC-MS/MS and LC-MS/MS/MS: Alternative validation according to Commission Implementing Regulation (EU) 2021/808

Nitrofurans are banned in food of animal origin in the European Union. A rugged liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and LC-MS/MS cubed (LC-MS/MS/MS) analytical method allowing the confirmation of five metabolites of nitrofuran antibacterial agents, furaltadone, furazolidone, nifursol, nitrofurantoin and nitrofurazone in animal muscle tissue was developed and validated. The validation of 1-aminohydantoin (AHD), 3-amino-5-methyl-morpholino-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ), 3,5-dinitrosalicylic acid hydrazide (DNSH) and semicarbazide (SEM) was carried out according to Commission Implementing Regulation (EU) 2021/808, by the adoption of a matrix-comprehensive in-house validation concept and the standard addition calibration. Validation was successfully performed, starting from 0.4 µg kg−1. Decision limit (CCα), recovery, repeatability, within-laboratory reproducibility and uncertainty of measurement were determined together with a factorial effect analysis. The procedure was verified through the analysis of two certified reference materials. The sample preparation consisted in acid hydrolysis and derivatization steps, followed by a liquid-liquid extraction of the analytes with ethylacetate.

A digital image-based colorimetric method for measuring free acidity in edible vegetable oils

The standard method used to quantify free acidity (FA) in vegetable oil is neutralization titration, which requires many toxic chemicals and depends on an analyst's experience in detecting endpoints. Here, a digital image colorimetry (DIC) method using a smartphone camera was developed to measure FA in vegetable oils. A cupric acetate solution was used to produce the colorimetric reaction. The coloured solutions were imaged, and R values (from the RGB colour system) were calibrated against the respective FAs in the standards. The FA values of the samples were determined by standard addition calibration. These results were compared to measurements of FA obtained by the standard titrimetric method. An excellent correlation was obtained, with an R2 of 0.98 and a mean absolute error of 0.06%. The chemicals needed for analysis were reduced by approximately 90%. Thus, DIC is a less subjective and more economical method for determining FA in vegetable oils.

Absolute contents of aroma-affecting volatiles in cooked rice determined by one-step rice cooking and volatile extraction coupled with standard-addition calibration using HS-SPME/GC–MS

To quantify volatiles in cooked rice, analysis methods for one-step rice cooking and volatile extraction in a single headspace vial, combined with standard addition calibration using solid-phase microextraction and GC–MS were developed and applied to 41 rice varieties with various fragrances and palatability. The newly developed methods significantly improved the qualitative and quantitative recovery of volatiles compared with conventional methods. Among 29 aroma-affecting volatiles, the highest average contents (ng/g) were observed for nonanal (39.30), octanal (13.29), and 1-octen-3-ol (13.18); the total volatile contents of aldehyde, base, and alcohol groups were 4156, 2481, and 1739 ng/g, respectively. Fifteen rice varieties contained 2-acetyl-1-pyrroline in range of 41.37–421.70 ng/g. Although there were no linear correlations among volatiles and the Toyo taste-score, multivariate PLS-DA analysis of the volatile could discriminate between low- and high-palatability rice varieties. The results indicated the accuracy and practicality of the newly developed methods for quantifying volatiles in cooked rice.

Dilute-and-shoot ICPMS quantification of V, Ni, Co, Cu, Zn, As, Se, Ag, Cd, Ba, and Pb in fruit juices based on matrix overcompensation calibration.

Analysis of V, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Ba, and Pb in fruit juices was performed by inductively coupled plasma mass spectrometry (ICPMS) after simple 50-fold dilution in 1% (v/v) HNO3-0.5% (v/v) HCl-5% (v/v) ethanol. Ethanol was added to overwhelm native organic components and dominate matrix effects. A universal calibration curve was built based on a likewise treated reagent standard series. This new matrix overcompensation calibration (MOC) strategy was developed to effectively compensated formatrix effects of carbon origin and achieved quantitative (92.5-118.8%) recoveries comparable to those by standard addition calibration (92.1-117.8%) and microwave-aided digestion (99.3-116.8%). The LODs were 0.528, 0.204, 0.195, and 2.07ngmL-1 for toxic elements As, Cd, Pb, and Ni, respectively, adequate for their regulatory monitoring. Ge, Rh, Tb, and Ir were used as internal standards. MOC renders a calibration curve universally applicable to any clear fruit juices of diversified crop, geographic, and manufacturer origins resulting in cost saving and enhanced productivity.

Application of Normal-Phase Silica Column in Hydrophilic Interaction Liquid Chromatography Mode for Simultaneous Determination of Underivatized Amino Acids from Human Serum Samples via Liquid Chromatography-Tandem Mass Spectrometry.

In neonatal screening, amino acids have a significant diagnostic role. Determination of their values may identify abnormal conditions. Early diagnosis and continuous monitoring of amino acid disorders results in a better disease outcome. An easy and simple LC-MS/MS method was developed for the quantitation of underivatized amino acids. Amino acids were separated using a normal-phase HPLC column having a totally porous silica stationary phase and using classical reversed-phase eluents. Mass spectrometry in multiple reaction monitoring mode was used for the analysis, providing high selectivity and sensitivity. A standard addition calibration model was applied for quantitation using only one isotope-labeled internal standard for all amino acids. Five calibration points were used for quantitation, and the method was successfully validated. The slopes of the calibration curves of the individual amino acids in parallel measurements were found to be similar. Since the measured slopes were reproducible, one serum sample could represent every series of serum samples of a given day. The method was tested on human serum samples and adequate results were obtained. This new method can be easily applied in clinical laboratories.

A Microfluidic Paper-based Analytical Device for Simultaneous Measurement of Albumin, Creatinine and Uric Acid in Urine based on Standard Addition Method

This work describes a simple method for the simultaneous measurement of urinary albumin, creatinine and uric acid using a standard addition approach on a microfluidic paper-based analytical device (µPAD). Hydrophobic barrier of the µPAD was created by stamping indelible ink onto a filter paper. The µPAD was designed with a flower-liked configuration. After aliquoting urine to a central sample zone, the sample flowed to ten surrounding channels, namely “the inner channels”, where the blank (water) or standard solutions had been added. The inner channels were connected to circular reagent zones where reagents had been immobilized. Tetrabromophenolphthalein ethyl ester, alkaline picrate, and a mixed solution of ferric chloride and ferric cyanide were used as the chromogenic reagents for the colorimetric detections of albumin, creatinine, and uric acid, respectively. Each reagent zone was linked with a circular detection zone through a second channel, namely “the outer channels”. The blue-, orange- and greenish-blue colored products were observed in the detection zones for the measurement of albumin, creatinine, and uric acid, correspondingly. A digital image of the µPAD was captured with a mobile phone. The color intensities were evaluated by ImageJTM and were employed for the quantitative analyses. The standard addition calibrations were found to be linear (r2 &gt; 0.99) for the spiked analyte concentrations up to 100 mg L-1 albumin, 1000 mg L-1 creatinine, and 50 mg dL-1 uric acid. The paper platform provided high precision (RSD &lt; 5 %) and good analytical recovery (91.8-109.7 %). Under paired t-test, the results obtained by the developed µPAD and the validating methods were not significantly different at 95 % confidence (albumin: tstat = -0.130, tcri = 3.182, creatinine: tstat = -0.133, tcri = 3.182, and uric acid: tstat = 1.119, tcri = 3.182).

A new direct extraction by gas-chromatography with flame ionization detector coupled to head space method for the determination of alcohol content of high matrix wine products

Detection, identification, and quantitation of alcohol in any matrix rich medium is a common practice although sample preparation is inevitable and time consuming. A sensitive, precise and ultimately wide range method for detection, identification and quantification of main content/residual/impurity alcohols without any matrix interference that can be used for production phase quality control, pharmaceutical and/or bio-technological refinement or toxicological evaluation and for forensics is always needed. Even for quality control also for toxicological considerations, ethanol (EtOH) and very similar compound methanol has to be detected and identified definitely becomes vital. However, with the fermented products, the matrix becomes a challenging process, makes the methods inefficient or more extraction methods have to be implanted. Here we propose a new simple and reliable direct extraction method has been developed for the determination of alcohol content of high matrix wine products using the gas-chromatography with flame ionization detector coupled to head space. The method was developed with a rich and complex component mixture of fermented alcoholic beverages (wine) with very high matrix effects. Isopropanol (IPA) was preferred as an internal standard, and Triton X-100 (TX-100) was used as diluting solution in this method. The amount of TX-100, extraction temperature, and the total volume of solution in head space vial (20 mL) were optimized. 2.5% TX-100, 80 °C extraction temperature, and 2.0 ml of total volume were used as optimum condition. Stationary phase was the fused silica, Agilent J&amp;W DB-624 column (30 m x 320 m x 1.8 m) and Helium was used as a mobile phase. GC oven temperature programme was 40C (5 min), 5C/min ramp to 60C (0 min) and 30C/min to 150C (1 min). Performance of the method was assessed by evaluating the recovery, accuracy, precision, linearity, limits of detection (LOD) and limit of quantification (LOQ). Calibration curve was drawn between the concentration of 2.5% to 15.0% EtOH (y = 1.572x – 0.702, R² = 0.9960, y; the ratio of peak area of EtOH to IPA, x: EtOH%). The slopes of standard addition and external calibration curve were statistically same. Recovery of the method was 97.5 ± 3.5 for tree different concentrations and the precision was %5.8 (n= 11). LOD and LOQ were calculated as 0.80% and 2.5%, respectively. The proposed method has a potential for application into the industry and academia with determination of the alcohol content/residual/impurity and also check the quality and content of the fermented medium without the effect of matrix.

Identification and quantification of ciprofloxacin, enrofloxacin and difloxacin residues in milk using excitation-emission fluorescence and second-order standard addition methods

In the presence of non-modeled components and analyte-matrix interaction in real samples, a combination of second-order multivariate calibration and standard addition is desired to achieve accurate results via second-order advantage. Enrofloxacin (ENR), Difloxacin (DIF), and Ciprofloxacin (CIP) are Fluoroquinolones widely considered antibiotic residues in milk. Excitation-emission fluorescence spectra of these antibiotics at pH = 9.1 provide second-order data for identifying and quantifying them in a mixture using second-order calibration modeling.Rank annihilation factor analysis (RAFA) and multivariate curve resolution-alternating least squares (MCR-ALS) with trilinearity constraints are applied to determine the CIP, ENR, and DIF residues in synthetic mixtures and milk using second-order excitation-emission fluorescence spectroscopy. In both methods, the trilinearity constraint guarantees a unique true solution to the spectral profiles of analytes. The combination of second-order standard addition and higher-order calibration modeling with RAFA and MCR-ALS supports the second-order advantage in milk analysis.

Improvements on the analysis methods of asphalt fumes generated in asphalt production and construction

Asphalt fumes are generated when producing and processing asphalt materials, and polycyclic aromatic hydrocarbons (PAHs) are commonly used as indicators to evaluate the hazardous potentials of asphalt fumes. However, the quantitative analysis of PAHs in asphalt fumes remains a challenge. Particularly, the influences of matrix compounds in asphalt fumes on PAH quantification have not been evaluated, even though matrix effect may lead to biased results. To address such a research gap, this study (1) examined the matrix effect in analyzing PAHs in asphalt fumes, (2) evaluated the effectiveness of clean-up methods, and (3) assessed the effectiveness of different methods for matrix effect compensation. Asphalt fumes from seven asphalt materials or conditions were collected and analyzed. Four clean-up methods were evaluated for their influences on PAH identification and matrix effect mitigation. Two approaches were experimented for matrix effect compensation. This study found an obvious matrix effect in the quantitative analysis of PAHs in asphalt fumes. None of the clean-up methods can effectively remove the matrix effect, but both the standard addition calibration (SAC) method and the internal standard calibration (ISC) method can compensate such effect. The findings are expected to assist in accurate quantification and evaluation of PAHs in asphalt fumes.

HS-SPME-GC-MS analysis of Cyprus vineyard soil for VOCs determination

In line with green chemistry principles, a headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was developed and optimized to study the profile of biogenic volatile organic compounds (BVOCs) in soil samples from vineyards. The 75 µm CAR/PDMS fiber was selected for the identification of BVOCs in soil. The analytical method showed very good linearity (R2 ≥ 0.9914), sensitivity, and precision. Subsequently, soil matrix effect (ME) was examined on the BVOCs emission, through combined standard addition and internal standard (IS) calibration curves. The validated and optimized method was further applied in real soil samples from three vineyard areas of Cyprus (Omodos, Polemi, and Agros). Thirty-eight BVOCs were identified in total; among them acetone (0.65–5.96 μg/kg), hexane (0–0.50 μg/kg), heptane (0–0.18 μg/kg), trichloromethane (0.13–0.21 μg/kg), 1,2-dichloropropane (0.05–1.37 μg/kg), cyclohexane (0–0.26 μg/kg), benzene (0–0.51 μg/kg), toluene (0–0.54 μg/kg), p-xylene (0.15–0.97 μg/kg), and 1,3-di-tert-butyl-benzene (7.91–29.55 μg/kg) were quantified. The results revealed that the sampling vineyard location affects the BVOCs emissions in each soil. Also, vineyard elevation, soil pH, Ca, N, Zn, and Fe showed a significant correlation with the BVOCs emissions, which explains why vineyard soil regions are distinguished from each other, concluding that sample from Agros is the most abundant in BVOCs emissions.

Overlooked Iodo-Disinfection Byproduct Formation When Cooking Pasta with Iodized Table Salt.

Iodized table salt provides iodide that is essential for health. However, during cooking, we found that chloramine residuals in tap water can react with iodide in table salt and organic matter in pasta to form iodinated disinfection byproducts (I-DBPs). While naturally occurring iodide in source waters is known to react with chloramine and dissolved organic carbon (e.g., humic acid) during the treatment of drinking water, this is the first study to investigate I-DBP formation from cooking real food with iodized table salt and chloraminated tap water. Matrix effects from the pasta posed an analytical challenge, necessitating the development of a new method for sensitive and reproducible measurements. The optimized method utilized sample cleanup with Captiva EMR-Lipid sorbent, extraction with ethyl acetate, standard addition calibration, and analysis using gas chromatography (GC)-mass spectrometry (MS)/MS. Using this method, seven I-DBPs, including six iodo-trihalomethanes (I-THMs) and iodoacetonitrile, were detected when iodized table salt was used to cook pasta, while no I-DBPs were formed with Kosher or Himalayan salts. Total I-THM levels of 11.1 ng/g in pasta combined with cooking water were measured, with triiodomethane and chlorodiiodomethane dominant, at 6.7 and 1.3 ng/g, respectively. Calculated cytotoxicity and genotoxicity of I-THMs for the pasta with cooking water were 126- and 18-fold, respectively, compared to the corresponding chloraminated tap water. However, when the cooked pasta was separated (strained) from the pasta water, chlorodiiodomethane was the dominant I-THM, and lower levels of total I-THMs (retaining 30% of the I-THMs) and calculated toxicity were observed. This study highlights an overlooked source of exposure to toxic I-DBPs. At the same time, the formation of I-DBPs can be avoided by boiling the pasta without a lid and adding iodized salt after cooking.

Simultaneous Rapid Determination of Seven Alternaria Toxins in Tuberous Crops during Storage Using QuEChERS Coupled with Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry

Robust and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied for the detection of seven Alternaria toxins (ATs) in tuberous crops. The influence of tuber conditions (fresh, germinated, and moldy) during storage on the concentration of the seven ATs is also investigated. ATs were extracted with acetonitrile under acidic conditions and purified with a C18 adsorbent. ATs were scanned with electrospray ionization (positive/negative ion) dynamic switching and detected in MRM mode. Calibration curve analysis results reveal good linear relationships in all toxin concentration ranges (R2 > 0.99). The limit of detection and limit of quantification were 0.25-0.70 and 0.83-2.31 μg/kg, respectively. The average recoveries of the seven ATs were 83.2-104% with intra-/inter-day precision at 3.52-6.55% and 4.02-7.26%, respectively. The developed method provided adequate selectivity, sensitivity, and precision in detecting the seven ATs at trace levels, and dispensed with standard addition or matrix-matched calibration to compensate for matrix effects. ATs in the fresh, germinated, and moldy samples of tuberous crops in storage (taro, potato, sweet potato, yam, cassava) were analyzed with this method, and the concentrations were 2.01-14.51 μg/kg and significantly increased with storage duration. ALS was detected in most samples, whereas no quantities of ALT and ATX-I were detected. AME was often detected in combination with AOH in sweet potatoes. TeA and Ten were mostly detected in taro, potato, and yam. The established method could be used for the simultaneous detection and quantification of multicomponent toxins in elaborate matrices.