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A highly sensitive and selective NH3 gas sensor was developed based on single-layer pristine graphene doped with copper(II) oxide (CuO) nanoparticles of a specific size. High-quality single-layer graphene was grown using chemical vapor deposition. Approximately 15 nm-sized CuO colloidal nanoparticles were fabricated by a microwave-assisted thermal method using copper acetate as the precursor, and dimethylformamide as the reducing and stabilizing agent. Pristine graphene was doped with an aqueous suspension of CuO nanoparticles at a coating speed of 1500 rpm using a simple spin coater. CuO nanoparticle doping induces changes in the electronic properties of graphene; in particular, p-type doping significantly altered graphene resistivity in the presence of NH3 gas. Upon exposure of the pristine graphene surface to NH3 gas, NH3 reacted with O2−/ O−/ O2− species on the graphene surface and released electrons into graphene. This caused a change in the concentration of charge carriers in the valence channel of graphene and an increase in graphene resistivity, facilitating real-time NH3 monitoring with quick response and rapid recovery at 25 ℃ and ~ 55% relative humidity. Our results indicated that graphene doped with ~ 15 nm-sized CuO nanoparticles can sense NH3 gas selectively with a resistivity response of ~ 83%. Moreover, the sensor exhibited good reusability, fast response (~ 19 s), and rapid recovery (~ 277 s) with a detection limit of 0.041 ppm and a relative standard deviation of 0.76%. [ABSTRACT FROM AUTHOR]

Intracellular H2O2 monitoring is important and has driven researchers to pursue advancements for the rapid identification of H2O2, since H2O2 is short-lived in cell lines. An arylboronate derivative has been investigated as a chemospecific fluorescence recognition agent for H2O2. Triphenylimidazoleoxadiazolephenyl (TPIOP) boronate was contrived as a novel candidate for the rapid and sensitive recognition of H2O2. The probe was conjugated using the TPIOP functional group acting as an excellent fluorescent enhancer. The TPIOP group stimulated the polarization of C–B bond due to its extended π-conjugation, which included heteroatoms, and induced the production of rapid signal because of the highly polar C–B bond along with the corresponding boronate unit. While H2O2 reacts with TPIOP boronate, its nucleophilic addition to the boron generates a charged tetrahedral boronate complex, and then the C–B bond migrates toward one of the electrophilic peroxide oxygen atoms. The resulting boronate ester is then hydrolyzed by water into a phenol, which significantly enhances fluorescence through aggregation-induced emission. The TPIOP boronate probe responded to H2O2 rapidly, within 2 min, and exhibited high sensitivity with a limit of detection of 8 nM and a 1000-fold selectivity in the presence of other reactive oxygen species. Therefore, the developed TPIOP boronate chemodosimeter was successfully utilized to visualize and quantify intracellular H2O2 from human breast cancer (MCF-7) cells, as well as gaseous and aqueous H2O2 from environmental samples using Whatman paper strips coated with TPIOP boronate. [ABSTRACT FROM AUTHOR]

A highly sensitive and selective colorimetric assay for the detection of Hg2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N–Hg2+–N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio (A700/A514) was correlated with the Hg2+ concentration in the linear range of 0.003–5.0 μM. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg2+ ions can be applied to the analysis of water and biological samples. [ABSTRACT FROM AUTHOR]

A sensitive colorimetric method for the determination of iodide ions was developed using gold nanoparticles (AuNPs) functionalised with glycol chitosan (GCS). The iodide ions were at the centre of the O–I––Ocoordination structure, formed with the GCS-AuNPs, reducing their interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry analyses showed that the bound iodide ions were coordinated to the oxygen atoms of the ethylene glycol in GCS, with this aggregation leading to a considerable variation in colour from light red to dark violet. Using this GCS-AuNP probe, the iodide ion concentration in environmental, biological and pharmaceutical samples could be determined by both the naked eye and UV-Vis spectroscopy. Additionally, the sensitivity of the detection was found to be markedly enhanced at pH 6, where a more pronounced colour change was observed. The absorption ratio A700/A521of the functionalised AuNP solution correlated linearly with the iodide ion concentration within the range 0.0–10.0 mg/L, and the limits of detection in tap water, pond water, and bovine serum solution were 3.5, 3.6, and 3.4 μg/L, respectively. The present assay method can thus be utilised to rapidly measure the concentration of iodide ions in aqueous samples. [ABSTRACT FROM PUBLISHER]

A highly sensitive and simple colorimetric assay for the detection of Fe3+ ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe3+ ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe3+-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe3+ was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe3+ in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe3+ were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio (A700/A510) linearly correlated to the Fe3+ concentration in the linear range of 0–180 μM. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe3+ ions can be applied to the analysis of drinking water and pharmaceutical samples. [ABSTRACT FROM AUTHOR]

A simple and facile colorimetric method for the detection of zinc ions (Zn 2+ ) using label-free silver nanoparticles (AgNPs) has been developed. Zn 2+ ions induced the aggregation of label-free AgNPs in solution, resulting in a color change from yellow to forest green, which was accompanied by the appearance of a new surface plasmon absorption band at 635 nm. The sensitivity of label-free AgNPs towards other metal ions was negligible, with the exception of Fe 3+ , which caused a modest interference. The binding site and sensing mechanism for Zn 2+ ions in label-free AgNPs were characterized by Fourier Transform infrared spectroscopy, ultraviolet-visible spectroscopy, and transmission electron microscopy. The aggregation of AgNPs in the presence of Zn 2+ ions was inhibited by polyvinyl alcohol, which formed a shell on the surface of AgNPs. Furthermore, Zn 2+ ions coordinated with BH 4 − on AgNPs through a triangular sixdentate binding structure, thus inducing aggregation of AgNPs in solution. The sensor conditions were optimized with 6.0 μM of sodium dodecylbenzenesulfonate (NaDDBS) and 0.23 mM AgNPs at pH 6. The absorption ratios (A 635 /A 390 ) of the label-free AgNPs solution exhibited a linear correlation with Zn 2+ ion concentration within the range of 0.0 − 7.6 × 10 −6 mol L −1 , with a limit of detection of 0.36 × 10 −6 mol L −1 . This cost-effective sensing system allows rapid and facile determination of Zn 2+ ions in various types of biological, mineral supplement, and environmental samples. [ABSTRACT FROM AUTHOR]

A simple and sensitive colorimetric method for the determination of Pb2+ ions in aqueous samples was developed using 1-(2-mercaptoethyl)-1,3,5-triazinane-2,4,6-trione (MTT) functionalized silver nanoparticles (MTT-AgNPs). The Pb2+ ion acted as the metal center of the coordination complex, which formed N–Pb2+–O coordination bonds with the MTT-AgNPs, shortening the interparticle distance, and inducing aggregation of the MTT-AgNPs. This aggregation resulted in a dramatic color change from yellow to dark blue. Using this methodology, the concentration of Pb2+ ions in environmental samples could be quantitatively detected with the naked eye or by using UV-vis spectrometry. Also, we found that the selectivity and sensitivity of detection were noticeably improved in the pH range of 7–8, at which a more obvious color change was observed. The absorption ratios (A625/A395) of the modified AgNP solution exhibited a linear correlation with Pb2+ ion concentrations within the linear range of 0.1–0.6 μg mL−1, and the limits of detection in tap and pond water were 0.02 and 0.06 μg mL−1, respectively. This cost-effective sensing system allows for the rapid and facile determination of Pb2+ ions in aqueous samples. [ABSTRACT FROM AUTHOR]

Document authentication is one of the most important fields in forensic science and includes analysis of handwriting, seal imprint, and printed materials. In this study, we investigated intersection lines by pen inks, red stamping ink, and laser toner using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR). TOF-SIMS is very useful when the quantity of the sample is insufficient or the sample is very precious. Each ink showed specific ion peaks from inorganic species such as Al, Si, Ti, Cr, Mn, Fe, Zn, and Pb and from organic components at a mass range of m/z 200-450 in TOF-SIMS spectra. ATR FTIR results also revealed different spectra for ink and toner samples. The overlapped area of ballpoint pen writing, red sealing stamping, and laser printing in a document was investigated in order to identify the sequence of recording. The sequence relations for various cases were studied from TOF-SIMS mapping image and ATR FTIR spectra. This study indicated that TOF-SIMS and ATR FTIR are useful techniques to determine the sequence of writing and printing under question. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• A Ni2+ ion probe based on the H 2 O 2 etching of triangular silver nanoprisms is presented here. • The etching of the triangular AgNPrs sculptured their sharp edges to circular Ag nanodisk. • The morphological transformation of the AgNPrs cause a color change from blue to yellow. • The present assay method can detect a Ni2+ ionic concentration of ˜21.6 nM within 30 min. In this article, a highly sensitive and selective colorimetric method for the detection of Ni2+ ions is presented on the basis of hydrogen peroxide etching of triangular silver nanoprisms (AgNPrs). Triangular AgNPrs were synthesized by a modified seed-mediated growth method, and upon addition of Ni2+ ions these triangular AgNPrs showed a significant colorimetric change from blue to reddish brown, and eventually yellow to as a function of the Ni2+ ion concentration. Ni2+ ion do not act as a selective etchant to triangular AgNPrs, but instead serve as a catalyst for the generation of H 2 O 2 in a citrate-capped triangular AgNPr colloidal solution. The oxidative etching with H 2 O 2 formed in the colloidal solution sculptured the sharp corners/edges of the triangular AgNPrs to produce circular Ag nanodisk. Selectivity tests for Ni2+ ions by the triangular AgNPr probe were performed in the presence of other various cations and anions at the optimized conditions (pH 8, 15 °C, and 30 min of reaction time). The probe showed a high linearity between absorption ratio (A 475 /A 750) and concentration in the range of 0 to 30 μM of Ni2+, with a limit of detection of 21.6 nM in aqueous solution. The color and UV–vis absorption spectrum of the triangular AgNPr probe indicated that it is quite stable for two weeks in ambient temperature and pH ranges of 4.0˜10.0. This triangular AgNPr probe was successfully employed for the detection of Ni2+ ions in spiked tap and pond water samples. [ABSTRACT FROM AUTHOR]

A tetraphenylethene (TPE) derivative was designed and synthesized upon conjugation with bis(thiophen-2-ylmethyl) amine (BTA) containing a mercury-binding moiety and further characterized by using Nuclear magnetic resonance (NMR), LC-MS, UV–Vis, and fluorescence spectroscopic methods. The resulting TPE-BTA exhibited comprehensive aggregation-induced emission while expressing a high quantum yield and emission intensity at 70% water fraction. The probe exhibited a good photochromic effect with a Stokes shift of 178 nm, and the emission intensity at 550 nm increased considerably with the color turning from dark green to bright green under a UV lamp upon the addition of 5 μM Hg2+. The lowest-energy conformation of the probe showed that two thiophene rings were perpendicular to the phenyl ring, while two BTA molecules were situated in a staggered form to each other. The sulfur and nitrogen atoms present in TPE-BTA were coordinated to the Hg2+ ion, and these binding sites were confirmed by the NMR parameters, X-ray photoelectron spectroscopy signals, and structural calculations. The binding of Hg2+ to TPE-BTA was believed to restrict the intramolecular motion of TPE-BTA, thus inducing it to shine brighter according to the unique aggregation-induced emission effect. The concentration of Hg2+ was determined based on the enhancement of the emission intensity, and the present probe showed an extremely high sensitivity with a limit of detection of 10.5 nM. Furthermore, TPE-BTA enabled selective detection of Hg2+ even in the presence of a 1000-fold excess of other interfering metal ions. The proposed method was successfully employed to determine Hg2+ in living HeLa cells and real water samples. Image 1 • A tetraphenylethene derivative (TPE-BTA) was designed and synthesized. • The molecular structures of TPE-BTA and TPE-BTA-2Hg2+ were proposed theoretically. • TPE-BTA showed highly sensitive and selective response for recognition of Hg2+. • The binding of Hg2+ to TPE-BTA induced it to shine brighter by the AIE effect. • TPE-BTA can be utilized as bioimaging reagent for Hg2+ in living HeLa cells. [ABSTRACT FROM AUTHOR]

Diagnosing cancer in its early stages can play an important role in prolonging the lifespan of patients, which demands the use of powerful tools to detect biomarkers accurately. However, since most fluorescent probes described for cancer diagnosis are limited to recognizing a single molecule, achieving the high accuracy criteria remains difficult. Here, sensor 1 is constructed for the sequential detection of D , ONOO - , and viscosity. Initially, sensor 1 detected D and underwent an intramolecular charge transfer mechanism, resulting in the formation of 2 and fluorescence quenching at 587 nm. Subsequently, the intermediate ( 2 ) monitored ONOO - and reproduced sensor 1 reversibly with fluorescence enhancement at 496 nm, showing concentration-related quantitative analysis. Similar sensing processes were observed in monitoring ONOO - and viscosity by synthetically developed sensor 2 . The proposed mechanisms of sensors 1 and 2 are verified through various characterizations ( 1 H NMR, HR-MS, and HPLC) and DFT calculations. Investigations on endogenous ONOO - and mitochondrial viscosity in cancer (HeLa) and normal (NCM460) cells were conducted to distinguish cancerous cells from normal cells. We anticipated that sensor 2 could effectively serve as a reliable bioanalytical reagent for cancer diagnosis at an earlier stage through sequential detection of two cancer markers, ONOO - and mitochondrial viscosity, in living cells. Importantly, sensor 2 has been employed for imaging ONOO - in normal and liver injury mouse models and tissues, achieving outstanding results.

A gold nanourchin (AuNU) probe with a novel sensing mechanism for monitoring H 2 S was developed as a feasible colorimetric sensor. In this study, AuNUs that are selectively responsive to H 2 S were fabricated in the presence of trisodium citrate and 1,4-hydroquinone using a seed-mediated approach. Upon exposure of the AuNU solution to H 2 S, the hydrosulfide ions (HS - ) in the solution are converted into oligomeric sulfides by 1,4-hydroquinone used as a reducing agent during the synthesis of AuNUs. The oligomeric sulfides formed in the AuNU solution upon the addition of H 2 S were found to coat the surface of the AuNUs, introducing a blue shift in absorption accompanied by a color change in the solution from sky blue to light green. This colorimetric alteration by the capping of oligomeric sulfides on the surface of AuNUs is unique compared to well-known color change mechanisms, such as aggregation, etching, or growth of nanoparticles. The novel H 2 S sensing mechanism of the AuNUs was characterized using UV-Vis spectroscopy, high-resolution transmission microscopy, X-ray photoelectron spectroscopy, surface-enhanced Raman spectroscopy, secondary ion mass spectroscopy, liquid chromatography-tandem mass spectrometry, and atom probe tomography. H 2 S was reliably monitored with two calibration curves comprising two sections with different slopes according to the low (0.3-15 μM) and high (15.0-300 μM) concentration range using the optimized AuNU probe, and a detection limit of 0.29 μM was obtained in tap water., Competing Interests: The authors have no conflict of interest in the publication of this manuscript., (This journal is © The Royal Society of Chemistry.)

Wheat and rice starches, traditionally used to stiffen fabric, become less contaminated and more antiseptic after fermentation for several years, thus enhancing their functional activity. In the present study, analytical techniques using particle size analysis, a gloss meter and a colorimeter were used to measure the physical properties of wheat and rice starches that had been fermented for 5 and 7 years, respectively. Their chemical contents and composition were determined by nutrient measurements and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The ToF-SIMS spectra and ion images showed that fermented starch contained more carbohydrate and less lipid than fresh starch. The surface morphologies of the fermented starch granules and starch-coated textiles were examined by scanning electron microscopy and compared with the surface morphologies of fresh starch granules. The fermented wheat and rice starch granules were smaller and more rounded with a lower level of N-containing compounds (proteins) and exhibited more antiseptic properties than fresh starch granules. The results showed that physical measurements and chemical analysis were simple and complementary techniques for investigating traditional Korean starch materials and textiles.

A highly sensitive and selective colorimetric assay for the dual detection of Hg 2+ and As 3+ using gold nanoparticles (AuNPs) conjugated with d-penicillamine (DPL) was developed. When Hg 2+ and As 3+ ions coordinate with AuNP-bound DPLs, the interparticle distance decreases, inducing aggregation; this results in a significant color change from wine red to dark midnight blue. The Hg4f and As3d signals in the X-ray photoelectron spectra of Hg 2+ (As 3+ )-DPL-AuNPs presented binding energies indicative of Hg 2+ -N(O) and As 3+ -N(O) bonds, and the molecular fragment observed in time-of-flight secondary ion mass spectra confirmed that Hg 2+ and As 3+ coordinated with two oxygen and two nitrogen atoms in DPL. The detection of Hg 2+ and As 3+ can be accomplished by observing the color change with the naked eye or by photometric methods, and this was optimized to provide optimal probe sensitivity. The assay method can be applied for environmental monitoring by first selectively quantifying Hg 2+ in water samples at pH 6, then estimating the As 3+ concentration at pH 4.5. The efficiency of the DPL-AuNP probe was evaluated for the sequential quantification of Hg 2+ and As 3+ in tap, pond, waste, and river water samples, and absorbance ratios ( A 730 / A 525 ) were correlated with Hg 2+ and As 3+ concentrations in the linear range of 0-1.4 μM. The limits of detection in water samples were found to be 0.5 and 0.7 nM for Hg 2+ and As 3+ , respectively. This novel probe can be utilized for the dual determination of Hg 2+ and As 3+ , even in the presence of interfering substances in environmental samples., Competing Interests: The authors have no conflict of interest in the publication of this manuscript., (This journal is © The Royal Society of Chemistry.)

Intracellular H 2 O 2 monitoring is important and has driven researchers to pursue advancements for the rapid identification of H 2 O 2 , since H 2 O 2 is short-lived in cell lines. An arylboronate derivative has been investigated as a chemospecific fluorescence recognition agent for H 2 O 2 . Triphenylimidazoleoxadiazolephenyl (TPIOP) boronate was contrived as a novel candidate for the rapid and sensitive recognition of H 2 O 2 . The probe was conjugated using the TPIOP functional group acting as an excellent fluorescent enhancer. The TPIOP group stimulated the polarization of C-B bond due to its extended π -conjugation, which included heteroatoms, and induced the production of rapid signal because of the highly polar C-B bond along with the corresponding boronate unit. While H 2 O 2 reacts with TPIOP boronate, its nucleophilic addition to the boron generates a charged tetrahedral boronate complex, and then the C-B bond migrates toward one of the electrophilic peroxide oxygen atoms. The resulting boronate ester is then hydrolyzed by water into a phenol, which significantly enhances fluorescence through aggregation-induced emission. The TPIOP boronate probe responded to H 2 O 2 rapidly, within 2 min, and exhibited high sensitivity with a limit of detection of 8 nM and a 1000-fold selectivity in the presence of other reactive oxygen species. Therefore, the developed TPIOP boronate chemodosimeter was successfully utilized to visualize and quantify intracellular H 2 O 2 from human breast cancer (MCF-7) cells, as well as gaseous and aqueous H 2 O 2 from environmental samples using Whatman paper strips coated with TPIOP boronate.

A highly sensitive and selective colorimetric assay for the detection of Hg 2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg 2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg 2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N-Hg 2+ -N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg 2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg 2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio ( A 700 / A 514 ) was correlated with the Hg 2+ concentration in the linear range of 0.003-5.0  μ M. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg 2+ ions can be applied to the analysis of water and biological samples.

A highly sensitive and simple colorimetric assay for the detection of Fe 3+ ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe 3+ ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe 3+ -O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe 3+ was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe 3+ in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe 3+ were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio ( A 700 / A 510 ) linearly correlated to the Fe 3+ concentration in the linear range of 0-180  μ M. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe 3+ ions can be applied to the analysis of drinking water and pharmaceutical samples.

A simple and sensitive colorimetric method for the determination of Pb(2+) ions in aqueous samples was developed using 1-(2-mercaptoethyl)-1,3,5-triazinane-2,4,6-trione (MTT) functionalized silver nanoparticles (MTT-AgNPs). The Pb(2+) ion acted as the metal center of the coordination complex, which formed N-Pb(2+)-O coordination bonds with the MTT-AgNPs, shortening the interparticle distance, and inducing aggregation of the MTT-AgNPs. This aggregation resulted in a dramatic color change from yellow to dark blue. Using this methodology, the concentration of Pb(2+) ions in environmental samples could be quantitatively detected with the naked eye or by using UV-vis spectrometry. Also, we found that the selectivity and sensitivity of detection were noticeably improved in the pH range of 7-8, at which a more obvious color change was observed. The absorption ratios (A625/A395) of the modified AgNP solution exhibited a linear correlation with Pb(2+) ion concentrations within the linear range of 0.1-0.6 μg mL(-1), and the limits of detection in tap and pond water were 0.02 and 0.06 μg mL(-1), respectively. This cost-effective sensing system allows for the rapid and facile determination of Pb(2+) ions in aqueous samples.

Residual quantities of 12 phthalates have been monitored in edible salts (raw salts, refined salts, refined salts with additives and baked salts) available in Korean food markets. Liquid-liquid extraction followed by liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) was used to analyse the samples. The method was validated and showed linear correlation (R² > 0.996) in the range 0.5-100 ng g⁻¹ for all target analytes. Recoveries were 85.9-108.4%, except for diethyl phthalate (DEP). Relative standard deviations (RSDs) were 2.7-6.0% and the limits of detection (LODs) were 1.2-2.8 ng g⁻¹. Although the contamination of phthalates in salt would be trivial in comparison to those of other main foods and below the reference dose of the Chronic Oral Exposure recommended by US-EPA, the availability of reference data could be valuable for food chemists and salt manufacturers.