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Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).

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Volatile aldehydes appear in canned vegetables as constituents and some of them can also be present as disinfection by-products (DBPs) because of the contact between vegetables and treated water. This paper describes two static headspace-gas chromatography-mass spectrometry (SHS-GC-MS) methods to determine 15 aldehydes in both the solid and the liquid phases of canned vegetables. The treatment for both phases of samples was carried out simultaneously into an SHS unit, including the leaching of the aldehydes (from the vegetable), their derivatization and volatilization of the oximes formed. Detection limits were obtained within the range of 15-400µg/kg and 3-40µg/L for aldehydes in the solid and the liquid phases of the food, respectively. The relative standard deviation was lower than 7% -for the whole array of the target analytes-, the trueness evaluated by recovery experiments provided %recoveries between 89 and 99% and short- and long-term stability studies indicated there was no significant variation in relative peak areas of all aldehydes in both phases of canned vegetables after their storing at 4°C for two weeks. The study of the origin of the 15 aldehydes detected between both phases of canned vegetables showed that: i) the presence of 13 aldehydes -at average concentrations of 2.2-39µg/kg and 0.25-71µg/L for the solid and the liquid phases, respectively- is because they are natural constituents of vegetables; and ii) the presence of glyoxal and methylglyoxal -which are mainly found in the liquid phase (average values, 1.4-4.1µg/L)- is ascribed to the use of treated water, thereby being DBPs.

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A novel, simple and automatic method based on static headspace-gas chromatography-mass spectrometry has been developed to determine 10 low-molecular mass aldehydes that can be found in beverages, coming from the treated water used in their production. These aldehydes are the most frequently found in treated water as water disinfection by-products, so they can be used as indicators of the addition of treated water to beverages. The study covered a large number of fruit juices and soft drinks. The presence of the whole array of analytes is related to the contact with treated water during beverage production, mainly by the addition of treated water as ingredient. In particular, propionaldehyde, valeraldehyde and benzaldehyde can be used as indicators of the addition of treated water in these kinds of beverages. Among the ten aldehydes, only formaldehyde and acetaldehyde are naturally present in all kinds of fruit, and their concentrations are related to stage of the ripening of the fruit.

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This paper described the first analytical method to simultaneously determine 14 disinfection by-products (DBPs) in meat products using microwave-assisted extraction (MAE) and static headspace (SHS) followed by gas chromatography-mass spectrometry (GC-MS). The DBPs included were 4 trihalomethanes, 7 haloacetic acids, 2 haloacetonitriles and trichloronitromethane, which are commonly formed as a consequence of the disinfection process of water. The combination of the MAE and SHS techniques allows meat samples to be analysed in two sequential steps into the same HS vial in spite of the sample's complexity. Detection limits were obtained within the range of 0.06-0.70ng/g, and the average relative standard deviation was 7.4%. Recoveries throughout the whole process were between 86 and 95%. The SHS-GC-MS method was applied to determine DBPs in meat products with different industrial processing which could be contaminated through contact with disinfectants and/or treated water employed in the factory either for washing or for the cooking of meat. Up to 5 DBPs were found at ng/g levels in about 36% of the samples analysed, cooked ham being the most contaminated meat product because of the brine solutions employed in its manufacturing process.

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The disinfection of water, equipment and surfaces in a cheese factory is one of the factors that can originate disinfection by-products (DBPs) in cheese. This research has focused on studying cheese factories in order to evaluate the individual contribution of each step of the cheese-making process that can contribute to the presence of DBPs in cheese. Ten factories were selected according to their salting processes (brine or dry salting). Each factory was monitored by the collection of six representative samples (factory water supply, brine solution, milk, whey, curd and cheese) in which the concentrations of up to eight chemicals were detected. The study shows that contact with brine solutions containing significant levels of DBPs is the main source of these chemicals in cheese. A minor factor is the pasteurised milk used in their manufacture.

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Canned vegetables come into contact with sanitizers and/or treated water in industry during several steps (namely washing, sanitising, blanching and filling with sauces or brine solutions) and therefore they can contain disinfection by-products - DBPs). This study focused on the occurrence of trihalomethanes (THMs) and haloacetic acids (HAAs) in a wide variety of canned vegetables (75 samples). For each vegetable, the edible solid and liquid phases of the package were separated and analysed individually. DBPs can be present in both solid (up to eight species) and liquid (up to 11 species) phases, their levels being higher in liquid ones. Volatile THMs predominate in the edible solid phase (up to four species), while HAAs do so in the liquid phase (up to five species) according to their ionic and non-volatile nature. The lowest concentrations of DBPs were found in tomatoes because they were often preserved in their own juice, without water.

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Canned vegetables appear to be a possible exposure pathway for hazardous disinfection by-products due to the use of sanitizers and treated water by the canning industry in the preparation of these foods. This work reports on two static headspace-gas chromatography-mass spectrometry methods for the simultaneous determination of 10 trihalomethanes (THMs) and 13 haloacetic acids (HAAs) in both solid and liquid phases of the canned vegetables. Both methods carry out the whole process (including the leaching of target analytes from the vegetable), derivatization of HAAs and volatilization of THMs and HAA esters, in a single step within a static headspace unit. The methods proposed provide an efficient and simple tool for the determination of regulated disinfection by-products in canned vegetables. Average limits of detection for THMs and HAAs were 0.19 and 0.45µg/kg, respectively, in the solid phase of canned vegetables, and 0.05 and 0.09µg/L, respectively, in the liquid phase. Satisfactory recoveries (90-99%) and precision, calculated as relative standard deviations (RSD≤10%), were obtained in both phases of canned vegetables. The methods proposed were applied for the analysis of frequently-used canned vegetables and confirmed the presence of up to 3 THMs and 5 HAAs at microgram per kilogram or liter levels in both phases of the samples.

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Cheese can contain regulated disinfection by-products (DBPs), mainly through contact with brine solutions prepared in disinfected water or sanitisers used to clean all contact surfaces, such as processing equipment and tanks. This study has focused on the possible presence of up to 10 trihalomethanes (THMs) and 13 haloacetic acids (HAAs) in a wide range of European cheeses. The study shows that 2 THMs, (in particular trichloromethane) and 3 HAAs (in particular dichloroacetic acid) can be found at µg/kg levels in the 56 cheeses analysed. Of the two types of DBPs, HAAs were generally present at higher concentrations, due to their hydrophilic and non-volatile nature. Despite their different nature (THMs are lipophilic), both of them have an affinity for fatty cheeses, increasing their concentrations as the percentage of water decreased because the DBPs were concentrated in the aqueous phase of the cheeses.

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Endogenous aldehydes (EAs) generated during oxidative stress and cell processes are associated with many pathogenic and toxicogenic processes. The aim of this research was to develop a solvent-free and automated analytical method for the determination of EAs in human urine using a static headspace generator sampler coupled with gas chromatography-mass spectrometry (HS-GC-MS). Twelve significant EAs used as markers of different biochemical and physiological processes, namely short- and medium-chain alkanals, α,ß-unsaturated aldehydes and dicarbonyl aldehydes have been selected as target analytes. Human urine samples (no dilution is required) were derivatized with O-2,3,4,5,6-pentafluorobenzylhydroxylamine in alkaline medium (hydrogen carbonate-carbonate buffer, pH 10.3). The HS-GC-MS method developed renders an efficient tool for the sensitive and precise determination of EAs in human urine with limits of detection from 1 to 15ng/L and relative standard deviations, (RSDs) from 6.0 to 7.9%. Average recoveries by enriching urine samples ranged between 92 and 95%. Aldehydes were readily determined at 0.005-50µg/L levels in human urine from healthy subjects, smokers and diabetic adults.

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In this study, we describe the synthesis of graphene oxide functionalized with the ionic liquid 1-butyl-3-aminopropyl imidazolium chloride and its use as an adsorbent for the dispersive solid-phase microextraction (micro SPE) of four anabolic steroids and six ß-blockers from aqueous samples of environmental importance, prior to their HPLC-diode array detector analysis. As the ionic liquid is covalently attached to graphene oxide sheets, it is made possible for it to participate in the dispersive micro SPE procedure. The limits of detection and limits of quantification of the proposed method were found to be in the range of 7-23ng/L and between 20 and 70ng/L, respectively. The linearity was satisfactory, with the determination coefficients to range from 0.9940 to 0.9998 while the within- and between-day relative standard deviation of the method ranged between 3.1 and 7.6% and from 4.0 to 8.5%, respectively. In order to test the applicability of the proposed method in real-life samples, the effluent from a municipal wastewater treatment plant as well as natural water samples from two rivers and a lake were collected and analyzed. After the analysis of samples, the effluent from municipal wastewater treatment plant was fortified with the analytes, at concentrations equal to 2 and 10 times the LOQs. Recoveries were calculated after subtracting the native (no-spike) concentrations of analytes, when needed. All the recoveries were in the range of 87-98%. A comparison study attests to the superiority of the developed nanomaterial over graphene oxide and graphene for the dispersive micro SPE of steroids and ß-blockers.

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Haloacetic acids (HAAs) are formed during the process of water disinfection. Therefore their presence in foods can be correlated with the addition of or contact with treated water. To determine the origin of HAAs in milk and dairy products, firstly a chromatographic method was developed for their determination. The sample treatment involves deproteination of milk followed by derivatization/extraction of the HAAs in the supernatant. About 20% of the foods analyzed contained two HAAs - which in no case exceeded 2 µg L(-1), that can be ascribed to contamination from sanitizers usually employed in the dairy industry. The process of boiling tap water (containing HAAs) for the preparation of powdered infant formula did not remove them; therefore it would be advisable to prepare this type of milk with mineral water (free of HAAs). In addition, it is possible to establish if the milk has been adulterated with treated water through the determination of HAAs.

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Trihalomethanes (THMs) and haloacetic acids (HAAs) are the two most prevalent classes of disinfection by-products (DBPs) that are present in treated water. Four THMs and six HAAs are regulated by several countries in drinking waters but no regulation for these DBPs has been established in foods. THMs are volatile species that can easily be determined by static headspace (SHS)-GC-MS, but HAAs require a derivatisation step to make them suitable for GC due to their polar and hydrophilic nature. This paper describes the first analytical method that performs the simultaneous determination of 10 THMs and 13 HAAs (chlorinated, brominated and iodinated) in cheeses by SHS in one unique GC-MS run. Parameters controlling leaching, centrifugation, derivatisation and volatilisation were optimised taking into account the high volatility of THMs and the thermal instability of HAAs. To increase sensitivity, 3g of cheese was extracted with 10mL of water at pH 4.5-7.7, and after centrifugation the supernatant (∼8mL) was introduced into an HS vial for the derivatisation (HAAs) and volatilisation (HAA esters and THMs) of the species in an automatic SHS unit coupled to GC-MS. Detection limits within the range of 0.05-0.50 and 0.15-0.85µg/kg for THMs and HAAs, respectively, were obtained, and the relative standard deviation was lower than 10% for all the target analytes. Recoveries throughout the whole method were between 85-90% and 92-97% for THMs and HAAs, respectively. The SHS-GC-MS method was applied for the determination of THMs and HAAs in 3 groups of Spanish cheeses, which can be contaminated through contact with treated water during the manufacturing steps. Up to 2 THMs and 4 HAAs were found at µg/kg levels in the samples analysed.

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Haloketones (HKs) are unregulated volatile disinfection by-products that show some potential risk even at low concentrations. While EPA Method 551.1 involves conventional liquid-liquid extraction and a complex series of steps, the simple scientific principles of solid-phase microextraction (SPME) in the headspace (HS) mode can be applied to ensure a solvent-free method to control these substances at appropriate levels. The 14 HKs (12 mL of water at pH∼1.5) were extracted on a DVB/CAR/PDMS fibre in 15min. After extraction, the analytes were desorbed at 250 °C in the GC-MS inlet. Parameters affecting the extraction/desorption steps were investigated to select the most favourable conditions in short times. The HS-SPME/GC-MS method demonstrated high extraction efficiency with low limits of detection of between 15 and 600 ng/L, good linearity in the range 0.05-2 µg/L to 100-2000 µg/L, and good repeatability (RSD below 7%, n=11). The green method was validated with EPA 551.1, used for determining halogenated VOCs in water, with noticeable advantages in terms of sensitivity, simplicity and solvent consumption. The results obtained from the analysis of water taken from a treatment plant employing chlorine dioxide and chloramines as disinfectants showed that two HKs were formed after pre-oxidation and that the subsequent steps in the plant were ineffective for their removal. Finally, the analysis of tap and swimming pool water exhibited that the concentration and number of species formed is higher in the latter, which is in accordance with its higher concentration of residual chlorine and organic matter.

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In this work, we studied a total of 46 regulated and non-regulated disinfection by-products (DBPs) including 10 trihalomethanes (THMs), 13 haloacetic acids (HAAs), 6 halonitromethanes (HNMs), 6 haloacetonitriles (HANs) and 11 aldehydes at different points in a drinking water treatment plant (DWTP) and its distribution network. Determining an increased number of compounds and using accurate, sensitive analytical methodologies for new DBPs can be useful to overcome some challenges encountered in the comprehensive assessment of the quality and safety of drinking water. This paper provides a detailed picture of the spatial and seasonal variability of DBP concentrations from raw water to distribution network. Samples were collected on a monthly basis at seven different points in the four seasons of a year to acquire robust data for DBPs and supplementary quality-related water parameters. Only 5 aldehydes and 2 HAAs were found in raw water. Chlorine dioxide caused the formation of 3 new aldehydes (benzaldehyde included), 5 HAAs and chloroform. The concentrations of DBPs present in raw water were up to 6 times higher in the warmer seasons (spring and summer). The sedimentation process further increased their concentrations and caused the formation of three new ones. Sand filtration substantially removed aldehydes and HAAs (15-50%), but increased the levels of THMs, HNMs and HANs by up to 70%. Chloramination raised the levels of 8 aldehydes and 7 HAAs; also, it caused the formation of monoiodoacetic acid, dibromochloromethane, dichloroiodomethane and bromochloroacetonitrile. Therefore, this treatment increases the levels of existing DBPs and leads to the formation of new ones to a greater extent than does chlorine dioxide. Except for 5 aldehydes, the 23 DBPs encountered at the DWTP exit were found at increased concentrations in the warmer seasons (HAAs by about 50% and THMs by 350%).

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A straightforward functionalization procedure is proposed for synthesizing a cotton-supported graphene as an extraction material, which is effectively employed for the extraction of multiclass pesticides from environmental waters prior to their determination by gas chromatography with mass spectrometry. Different experimental parameters that affect the extraction efficiency, including pH of the extraction, stirring rate, extraction time, ionic strength, presence of humic acid, sample volume, amount of sorbent, and elution conditions, were investigated and properly established. The advantages of the present extraction method are the simplicity of implementation, rapidity, and low consumption of sorbent per extraction. Moreover, the pesticides on the adsorbent are stable, under certain storage conditions, rendering the cotton-supported graphene suitable for environmental field studies. The applicability of the cotton-graphene-based procedure for routine analysis was demonstrated by the determination of pesticides in a lake water sample. The recoveries ranged from 83 to 107%, the limits of quantitation were in the range of 0.02-0.09 µg/L, and the calculated relative standard deviations varied from 3 to 8% (data obtained with the same batch of sorbent). Because of the acceptable analytical characteristics, the developed method shows great prospects in determining certain classes of pesticides in water.

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Water used in a food factory is frequently disinfected with chlorine, which originates disinfection by-products: haloacetic acids (HAAs) make up the second most prevalent class of these products. In this paper we propose the first static HS-GC-MS method developed for direct HAA determination in beverages; the method has higher sensitivity, simplicity and reliability than the only alternative available in the literature. From 150 beverages analysed, it is possible to conclude that at least 2 HAAs (dichloro- and trichloroacetic acids, DCAA and TCAA) are always present in beverages prepared with treated water, which remains constant for 2 or 3 months in the beverages. Moreover, beverages of 100% fruit juices and soft drinks prepared with mineral water (free of HAAs) do not contain any HAA at significant values. Therefore, DCAA and TCAA may indicate of the presence of treated water in beverages.

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A simple, robust, and reliable headspace gas chromatography method has been developed for the determination of 14 halogenated volatile organic compounds, including iodinated trihalomethanes (THMs), at nanogram per liter levels in beverages. The main source of the presence of THMs in reconstituted fruit juices, nectars, and soft drinks is the treated water included as an ingredient; the concentration and speciation depend on the volume and disinfection process of the treated water either from the distribution network or from water directly disinfected by the food factory. Chloroform appears at concentrations below 1 µg/L in natural juices and soft drinks prepared with mineral water due to contamination from the chlorinated sanitizers usually employed in the food industry. However, the beverages manufactured with treated water contain, in addition to chloroform, brominated THMs and dichloroiodomethane (detected in beverages for the first time), which can be used as indicators of the presence of treated water.

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Perfluoroalkyl acids are an important class of synthetic compounds widely used in commercial and residential settings, which may have potential adverse health effects. The objective of this study was to monitor 6 perfluorocarboxylic acids and perfluorooctane sulphonate in human urine to obtain a way to asses exposure. The target analytes were extracted from urine by using a semi automated solid-phase extraction module and derivatised with isobutyl chloroformate by catalysis with 3% N,N-dicyclohexylcarbodiimide in pyridine. Determination and quantisation were achieved by gas chromatography with a mass spectrometer detector operating in the selected-ion monitoring mode. The developed approach is fast and provided low limits of detection (0.2-1.0 ng L(-1)) with good precision (relative standard deviation lower than 7.5%, within-day and between day). Recoveries from urine samples, which were spiked with the studied compounds at levels of 10 and 50 ng L(-1) ranged from 93% to 96%. Perfluorohexanoic (≤ 70 ng L(-1)) and perfluoroheptanoic acids (<2 ng L(-1)) were found in the urine samples from exposed researchers taken after handling these compounds. From the calculation of the excretion kinetics it was found that the dosage absorbed was eliminated within 15 h after exposure.

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Several groups of organic compounds have emerged as being particularly relevant as environmental pollutants, including disinfection by-products (DBPs). Haloketones (HKs), which belong to the unregulated volatile fraction of DBPs, have become a priority because of their occurrence in drinking water at concentrations below 1µg/L. The absence of a comprehensive method for HKs has led to the development of the first method for determining fourteen of these species. In an effort to miniaturise, this study develops a micro liquid-liquid extraction (MLLE) method adapted from EPA Method 551.1. In this method practically, the whole extract (50µL) was injected into a programmed temperature vaporiser-gas chromatography-mass spectrometer in order to improve sensitivity. The method was validated by comparing it to EPA Method 551.1 and showed relevant advantages such as: lower sample pH (1.5), higher aqueous/organic volume ratio (60), lower solvent consumption (200µL) and fast and cost-saving operation. The MLLE method achieved detection limits ranging from 6 to 60ng/L (except for 1,1,3-tribromo-3-chloroacetone, 120ng/L) with satisfactory precision (RSD, ∼6%) and high recoveries (95-99%). An evaluation was carried out of the influence of various dechlorinating agents as well as of the sample pH on the stability of the fourteen HKs in treated water. To ensure the HKs integrity for at least 1 week during storage at 4°C, the samples were acidified at pH ∼1.5, which coincides with the sample pH required for MLLE. The green method was applied to the speciation of fourteen HKs in tap and swimming pool waters, where one and seven chlorinated species, respectively, were found. The concentration of 1.1-dichloroacetone in swimming pool water increased ∼25 times in relation to tap water.

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