Liquid-phase microextraction of aromatic amines: hollow fiber-liquid-phase microextraction and parallel artificial liquid membrane extraction comparison.

Aromatic amines (AA) are carcinogenic compounds that can enter the human body through many sources, one of the most important being tobacco smoke. They are excreted with the urine, from which they can be extracted and measured. To that end, hollow fiber-liquid-phase microextraction (HF-LPME) and parallel artificial liquid membrane extraction (PALME) were optimized for the analysis of representative aromatic amines, as alternatives to liquid-liquid extraction (LLE). Relevant extraction parameters, namely organic solvent, extraction time, agitation speed, and acceptor solution pH, were studied, and the two optimized techniques-HF-LPME: dihexyl ether, 45 min, 250 rpm, and pH 1; PALME: undecane, 20 min, 250 rpm and pH 1-were compared. Comparison of the optimized methods showed that significantly higher recoveries could be obtained with PALME than with HF-LPME. Therefore, PALME was further validated. The results were successful for nine different AA, with regression coefficients (R2) of at least 0.991, limits of detection (LOD) of 45-75 ng/L, and repeatability and peak area relative standard deviations (RSD) below 20%. Furthermore, two urine samples from smokers were measured as proof of concept, and 2-methylaniline was successfully quantified in one of them. These results show that PALME is a great green alternative to LLE. Not only does it use much smaller volumes of toxic organic solvents, and sample-enabling the study of samples with limited available volumes-but it is also less time consuming and labor intensive, and it can be automated.

In-tube dynamic extraction for analysis of volatile organic compounds in honey samples.

Honey is the oldest and nowadays widely used natural sweetener for food worldwide. Its composition is associated with its botanical and geographical origin and honey is often mislabeled and has a high potential for food fraud. Thus, quick easy and sensitive analyses are required. For the first time, we developed and applied an automated, fast, sensitive and robust, in-tube extraction dynamic headspace in-tube extraction-dynamic headspace (ITEX-DHS) method for a variety of Honey containing VOCs in connection with GC-MS. Another advantage of ITEX is, that it is a green analytical solventless method. The method provides very low method detection limits (MDL) from 0.8 to 47 ng g-1 for VOCs in honey samples as well as very good repeatabilities with averages below 9 % RSD. Recoveries are between 83 and 100 %. Only octanal possess a repeatability 13 % and a recovery of 62 % due to its high polarity. 38 honey samples were measured after method validation. Four acacia honeys (A), six forest honeys (F) and 22 blossom honeys (B). The type of six honeys was not known (U) but could be predicted with the help of a linear discriminant analysis (LDA). The LDA was carried out with the three groups (A, B, F) leading to a proportion of correct predictions of 90.6 %. With the help of a scatterplot, two of the unknown samples were classified as forest honeys and four of them as blossom honeys.

Ultrafast cold-brewing of coffee by picosecond-pulsed laser extraction.

Coffee is typically brewed by extracting roasted and milled beans with hot water, but alternative methods such as cold brewing became increasingly popular over the past years. Cold-brewed coffee is attributed to health benefits, fewer acids, and bitter substances. But the preparation of cold brew typically needs several hours or even days. To create a cold-brew coffee within a few minutes, we present an approach in which an ultrashort-pulsed laser system is applied at the brewing entity without heating the powder suspension in water, efficiently extracting caffeine and aromatic substances from the powder. Already 3 min irradiation at room temperature leads to a caffeine concentration of 25 mg caffeine per 100 ml, comparable to the concentrations achieved by traditional hot brewing methods but comes without heating the suspension. Furthermore, the liquid phase's alkaloid content, analyzed by reversed-phase liquid chromatography coupled to high-resolution mass spectrometry, is dominated by caffeine and trigonelline and is comparable to traditional cold-brewed coffee rather than hot-brewed coffee. Furthermore, analyzing the head-space of the prepared coffee variants, using in-tube extraction dynamic head-space followed by gas chromatography coupled to mass spectrometry, gives evidence that the lack of heating leads to the preservation of more (semi-)volatile substances like pyridine, which provide cold-brew coffee its unique taste. This pioneering study may give the impetus to investigate further the possibility of cold-brewing coffee, accelerated by more than one order of magnitude, using ultrafast laser systems.

BTEX compounds leachates from cigarette butts into water environment: A primary study.

Cigarette butts (CBs) are the most abundant types of litter in the environment and may contain toxic chemicals such as BTEX that pose serious risks to the water bodies and health of aquatic organisms. So far there is no systematic study on BTEX compounds (benzene, toluene, ethylbenzene, o-xylene, and p-xylene) leaching from CBs into water environments. In this work, the leaching concentrations of BTEX compounds in deionized water (DW) and river water (RW) samples were studied for the first time. The mean concentrations of benzene, toluene, ethylbenzene, p-xylene, and o-xylene at contact times of 15 min to 1 day in water samples ranged from 0.13 to 0.18, 0.39-0.9, 0.11-0.25, 0.12-0.38, and 0.09-0.19 µgL-1 respectively. Benzene, toluene, ethylbenzene, o-xylene and p-xylene were detected at all contact times in both DW and RW samples. There were no significant differences of the leachate levels of BTEX compounds between DW and RW samples. The highest and lowest mean concentration levels in both DW and RW samples were determined for toluene and o-xylene respectively. The time after smoking had a significant effect on BTEX levels in leachates. The concentration levels of benzene, toluene, ethylbenzene, o-xylene and p-xylene leachates in water samples, after only 15 min, were reduced by 100, 93, 70, 68, and 59 percent respectively. Our data revealed that leached concentrations of benzene did not exceed the Water Framework Directive (WFD) guidelines, but with regard to the amount of CBs littered each year and other toxic chemicals contents of CBs this can still be a threat for aquatic creatures and possibly humans as well. Further studies are needed to cover the knowledge gap on the toxic leachates from CBs into water systems.

Optimization and validation of automated solid-phase microextraction arrow technique for determination of phosphorus flame retardants in water.

In the present work, a very sensitive and fully automated direct immersion PAL SPME Arrow procedure, coupled with GC-MS, has been developed and validated for determination of nine phosphorus flame retardants in different types of water samples (river, drinking and rainwater). PDMS/DVB was selected among three commercially available SPME Arrows (PDMS/DVB, DVB/PDMS/CWR and PDMS/CWR), since it resulted in the best sensitivity. The important experimental parameters were optimized via a central composite design response surface methodology and as result, extraction time of 65 min, extraction temperature of 80 °C and added salt concentration of 19% (w/v), were selected as the optimum values. The optimized method showed linear response over the calibration range (2 - 500 ng L-1), with R2-values higher than 0.9937. The precision (RSD%) measured by replicate analyses (n = 7) was estimated at 2 and 100 ng L-1 and was less than 29% and 21%, respectively. The LOQ of PAL SPME Arrow, calculated as S/N = 10, was between 0.2 and 1.2 ng L-1 (for triphenyl phosphate and tris-(1­chloro­2-propyl) phosphate, respectively) with extraction efficiencies between 5.9 and 31% (for tris-(1,3-dichloro-2-propyl) phosphate and tri-n­butyl phosphate, respectively). To assess the performance of the developed technique for real samples, two river water samples, tap water from two regions and a rainwater sample were analyzed. Most of the target analytes were observed in the river samples with concentrations of 1.0 - 250 ng L-1 and the obtained recoveries at 50 ng L-1 ranged between 60 and 107%. Considering the figures of merit of the optimized method, PAL SPME Arrow-GC-MS showed to be the most sensitive analytical approach for determination of phosphorus flame retardants in water, with satisfying precision and accuracy, compared with conventional SPME-NPD, LLE-GC-MS and SPE-LC-MS/MS.

Polycyclic aromatic hydrocarbons (PAHs) leachates from cigarette butts into water.

Cigarette butts (CBs) are the most common littered items in the environment and may contain high amounts of polycyclic aromatic hydrocarbons (PAHs) from incomplete tobacco leave burning. The potential relevance of PAHs stemming from CBs for aquatic systems remain unclear since to date there is no systematic study on PAHs leaching from CBs. Therefore, in this study the leaching concentrations of 16 EPA-PAHs (except benzo(ghi)perylene) in 3 different types of water were measured. The concentrations of ΣPAHs leachates from 4 h to 21 days ranged from 3.9 to 5.7, 3.3-5.5, and 3.0-5.0 µg L-1 for deionized, tap, and river waters, respectively. For all contact times, there were no substantial differences of the leachate concentrations of PAHs among different water types. Lighter PAHs had the highest concentrations among the detected PAHs and they were detected in the leachates already after 4 h. Concentrations of indeno(1,2,3-cd)pyrene, and dibenz(a,h)anthracene were below the limit of detection in all water samples at different contact times. At all contact times naphthalene and fluorene had the highest concentrations among the studied PAHs. Tap and river water samples with addition of sodium azide as chemical preservative contained significantly higher concentration of ΣPAHs. Our leaching data showed that leached concentrations of PAHs exceeded the Water Framework Directive (WFD) standards and considering the number of CBs annually littered this may pose a risk to aquatic organisms and potentially also humans.