Standard Addition Approach Research Articles

Alternative QuEChERS-based modular approach for pesticide residue analysis in food of animal origin.

The approach for pesticide residue analysis in food of animal origin differs strongly from the one established for food of plant origin, as laboratories mainly focus on conventional methods for the analysis of non-polar pesticides known to accumulate in fatty tissues. However, these group-specific methods are very laborious and cost intensive and typically require extraction of fat components followed by extensive clean-up steps to remove matrix constituents. This work highlights the development and validation of a straightforward QuEChERS-derived clean-up procedure enabling facile, precise, and reliable identification and quantitation of pesticide residues in food of animal origin, which can be extended to various other commodities with moderate fat content and applied to replace traditional group-specific methods. Two additional methods for lean and highly fatty commodities complete this well-established "simplified modular system". The proposed method was in-house validated in terms of accuracy and precision, recovery and linearity as well as specificity and sensitivity on two representative commodities for food of animal origin (egg and meat). For the majority of the more than 80 pesticides investigated, satisfactory results were obtained. Procedural matrix calibration was applied for screening purposes in conjunction with GC-MS/MS or LC-MS/MS as integral part of the approach. Apparent recoveries for most of the compounds ranged from 70 to 120 % (RSD < 20%) at spiking levels of 0.01 (LOQ level) and 0.05 mg/kg. Accuracy of the method has been demonstrated by application to reference material from previous EU proficiency tests. Only in case of positive screening results a standard addition approach was applied for precise quantitation.

An LCMS method for the assay of melittin in cosmetic formulations containing bee venom.

There is a growing interest in the potential of bee venom in cosmetics as a rejuvenating agent. Products currently on the market do not specify exactly their content of bee venom (BV). Therefore, we developed a method for the detection and quantification of melittin, as a marker of bee venom content, in selected commercial creams which contained BV according to their marketing claims, in order to gauge the relative quality of such formulations. A quantitative method was achieved following a rigorous extraction procedure involving sonication, liquid-liquid extraction and solid phase extraction since carryover of excipients was found to cause a rapid deterioration in the chromatographic performance. The method employed a standard additions approach using, as spiking standard, purified melittin isolated from bee venom and standardised by quantitative NMR. The aqueous extracts of the spiked creams were analysed by reversed phase LCMS on an LTQ Orbitrap mass spectrometer. The purity of the melittin spiking standard was determined to be 96.0%. The lowest measured mean melittin content in the creams was 3.19 ppm (±1.58 ppm 95% CI) while the highest was 37.21 ppm (±2.01 ppm 95% CI). The method showed adequate linearity (R (2) ≥ 0.98) and a recovery of 87.7-102.2% from a spiked blank cream. An assay precision of <20% RSD was achieved for all but one sample where the RSD value was 27.5%. The method was sensitive enough for use in routine assay of BV-containing cosmetic creams. Differences in the melittin content of the commercial products assayed were nearly tenfold.

Non-linear effects in quantitative 2D NMR of polysaccharides: Pitfalls and how to avoid them

Quantitative 2D NMR is a powerful analytical tool which is widely used to determine the concentration of small molecules in complex samples. Due to the site-specific response of the 2D NMR signal, the determination of absolute concentrations requires the use of a calibration or standard addition approach, where the analyte acts as its own reference. Standard addition methods, where the targeted sample is gradually spiked with known amounts of the targeted analyte, are particularly well-suited for quantitative 2D NMR of small molecules. This paper explores the potential of such quantitative 2D NMR approaches for the quantitative analysis of a high molecular weight polysaccharide. The results highlight that the standard addition method leads to a strong under-estimation of the target concentration, whatever the 2D NMR pulse sequence. Diffusion measurements show that a change in the macromolecular organization of the studied polysaccharide is the most probable hypothesis to explain the non-linear evolution of the 2D NMR signal with concentration. In spite of this non-linearity – the detailed explanation of which is out of the scope of this paper – we demonstrate that accurate quantitative results can still be obtained provided that an external calibration is performed with a wide range of concentrations surrounding the target value. This study opens the way to a number of studies where 2D NMR is needed for the quantitative analysis of macromolecules.

Quantitative trace analysis of complex mixtures using SABRE hyperpolarization.

Signal amplification by reversible exchange (SABRE) is an emerging nuclear spin hyperpolarization technique that strongly enhances NMR signals of small molecules in solution. However, such signal enhancements have never been exploited for concentration determination, as the efficiency of SABRE can strongly vary between different substrates or even between nuclear spins in the same molecule. The first application of SABRE for the quantitative analysis of a complex mixture is now reported. Despite the inherent complexity of the system under investigation, which involves thousands of competing binding equilibria, analytes at concentrations in the low micromolar range could be quantified from single-scan SABRE spectra using a standard-addition approach.

Quantitative Trace Analysis of Complex Mixtures Using SABRE Hyperpolarization

Signal amplification by reversible exchange (SABRE) is an emerging nuclear spin hyperpolarization technique that strongly enhances NMR signals of small molecules in solution. However, such signal enhancements have never been exploited for concentration determination, as the efficiency of SABRE can strongly vary between different substrates or even between nuclear spins in the same molecule. The first application of SABRE for the quantitative analysis of a complex mixture is now reported. Despite the inherent complexity of the system under investigation, which involves thousands of competing binding equilibria, analytes at concentrations in the low micromolar range could be quantified from single-scan SABRE spectra using a standard-addition approach.

Transfer of TLC screening methods designed for use in developing countries to quantitative HPTLC-densitometry methods for diazepam and amodiaquine tablets

Transfer of two rapid thin-layer chromatography (TLC) screening methods used to detect markedly substandard and fake pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods is demonstrated using a model procedure that was published earlier. These TLC methods for diazepam and amodiaquine are contained in a Compendium of methods by Kenyon and Layloff and a Minilab method manual from Global Pharma Health Fund E.V., respectively, for use in countries with limited resources. Merck HPTLC Premium Purity silica gel 60 F254 glass plates, automated standard and sample solution application with a CAMAG Linomat 4, and automated densitometry with a CAMAG Scanner 3 were used for detection, identification, and quantification. Sample peak identity and purity validation were carried out by spectral comparison checks available in the winCATS software. Accuracy was estimated by the standard addition approach with overspotting standard and sample solutions. HPTLC gives better efficiency, sel...

Automated Determination of Cu(II), Pb(II), Cd(II) and Zn(II) in Environmental Samples by Square Wave Voltammetry Exploiting Sequential Injection Analysis and Screen Printed Electrodes

AbstractThis paper describes the development of a methodology for quantification of Cu(II), Pb(II), Cd(II) and Zn(II) in waters and sediments by anodic stripping voltammetry (ASV) automated by Sequential Injection Analysis (SIA) using a graphite screen printed sensor modified with mercury. Determinations were made by standard addition automated by the SIA system. The limits of detection and quantification were, respectively, 1.3 and 4.3 µg L−1 for Cu(II), 1.4 and 4.6 µg L−1 for Pb(II), 0.6 and 1.8 µg L−1 for Cd(II) and 4.2 and 14 µg L−1 for Zn(II). These limits were obtained for a sample volume of 1000 µL, flow rate of 10 µL s−1 (during the deposition step), and utilizing 3 flow reversals (volume of reversion=950 µL), totalizing a deposition time of 315 s. The potentiostat worked synchronically with the SIA system applying the conditioning potential of −0.1 V vs. pseudo reference of Ag (100 s), deposition potential of −1.0 V for Cu(II), Pb(II) and Cd(II) or −1,3 V for Zn(II), square wave frequency of 100 Hz, potential step of 6 mV and pulse height of 40 mV. For quantification of Zn(II) in sediment extracts, deposition of Ga0 on the working electrode was necessary to avoid the formation of intermetallic between Zn0 and Cu0. The accuracy of the method was assessed by spike and recovery experiments in water samples which resulted recovery rates near 100 % of the spiked concentrations. Recoveries of concentrations in the certified sediment sample CRM‐701 undergoing the three steps sequential extraction procedure of BCR varied from 71.7 % for Zn(II) in the acetic acid extract to 112.4 % for Cu(II) in the oxidisable fraction, confirming that the standard addition approach corrected the matrix effects in the complex samples of sediment extracts.

Quantitative determination and confirmatory analysis of N-acetylneuraminic and N-glycolylneuraminic acids in serum and urine by solid-phase extraction on-line coupled to liquid chromatography–tandem mass spectrometry

N-acetylneuraminic acid (Neu5Ac) and N-acetylglycolylneuraminic acid (Neu5Gc), two acylated derivatives of 9-C carboxylated monosaccharides, are involved in a number of biological processes as modulators of glycoconjugates. A partially automated method is here presented for determination of these sialic acids in the two most important biofluids for clinical analysis: serum and urine. For this purpose, a solid-phase extraction (SPE) workstation was on-line connected to an LC–MS/MS triple quadrupole mass detector. Hydrolysis to release sialic acids bound to glycoconjugates and derivatization were the two steps implemented as sample preparation prior to SPE–LC–MS/MS analysis. Following thorough optimization of the SPE and LC–MS/MS conditions, the analytical method was validated using the standard addition approach to assess the presence of matrix effects. The proposed method affords detection limits of 0.03ng/mL and 0.04ng/mL for Neu5Ac and Neu5Gc, respectively. The precision (expressed as relative standard deviation) was 1.7 and 4.6% for within-day variability, and 4.8 and 7.2% for between-days variability. Accuracy, estimated using spiked (between 1 and 50ng/mL) and non-spiked samples of both biofluids, ranged from 95.2 to 99.6%. The method was applied to human serum and urine of healthy volunteers, thus showing its suitability for application in both clinical and research laboratories.

Quantitative Analysis of Long Chain Fatty Acids Present in a Type I Kerogen Using Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Compared with BF3/MeOH Methylation/GC-FID

Long chain fatty acids (LCFAs) are present in various natural samples and are easily detectable using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) in negative ion mode. The capability of the ESI-FT-ICR-MS for quantifying LCFAs was evaluated by performing a standard addition followed by an internal standard methodology to several kerogen extracts using n-C₂₀ fatty acid as standard. As the concentration of the standard increased, the magnitude of its peak (m/z 311.29525) increased linearly but with two separate slopes, leaving the entire mass spectra relatively unchanged, which shows evidence of reproducibility. Response factors of other LCFAs are obtained using a standard addition approach. We employed five LCFA standards (n-C₁₅, n-C₁₉, n-C₂₄, n-C₂₆, and n-C₃₀) with different carbon numbers. This allowed us to determine the response factor of all fatty acids (with carbon number between 15 and 30) by plotting the slope of each standard versus its carbon number. With the observed response factors and use of the internal standard, the concentrations of LCFAs in four kerogen extracts were measured by ESI-FT-ICR-MS and compared with those from GC-FID. The carbon number distribution obtained by ESI-FT-ICR-MS matched well the GC-FID distribution (5%–50%) with the exception of C₁₆ and C₁₈, considering that ESI-FT-ICR-MS does not differentiate between normal and branched LCFAs, whereas GC-FID does. This allows one to quantitatively compare samples with a relatively similar matrix for specific compounds such as LCFAs with no need of time-consuming derivatization procedures. Moreover, the calibration can be extended to higher carbon numbers with ESI-FT-ICR-MS, beyond the capabilities of GC/MS.

Development of analytical method for determination of 1,4‐dioxane in cleansing products

1,4-Dioxane is a toxic by-product formed during the synthesis of surfactants used in finished cosmetic products. There are no set permissible levels of toxic impurities in finished cosmetic products in Japan. In this study, we have established a simple and sufficiently precise analytical method to determine the activity of 1,4-dioxane in finished cosmetic cleansing products. This method involves the standard addition approach and headspace-gas chromatography/mass spectrometry without pre-conditioning. Fifteen cleansing products that are sold in the Japanese market, such as shampoo, hand soap, and dishwashing liquid, were analyzed, and 1,4-dioxane was detected at a concentration of a few micrograms per gram of the product in almost all of them. The concentration of 1,4-dioxane in two dishwashing liquid products was high. The maximum concentration of 1,4-dioxane in all of the cleansing products was below 10μgg(-1) , which is a limit that is thought to be safe and technically achievable through the application of good manufacturing practices. Since 1,4-dioxane is formed during the synthesis of polyoxyethylene ether sulfate, it was detected at high concentrations in cleansing products that contained a lot of polyoxyethylene ether sulfate. Control of the synthesis of polyoxyethylene ether sulfate can be effective in reducing the concentration of 1,4-dioxane in cleansing products.

Cross-validation of analytical procedures for the reliable determination of Nd concentrations in nuclear fuel using ICP-OES and sector field ICP-MS

This study focussed on the development and validation of straightforward ICP-OES and sector field ICP-MS procedures for the accurate determination of the neodymium (Nd) concentration in nuclear samples. After dissolution of a spent fuel in a chemical hot cell, Nd was analysed in the acidic solution without prior separation of any fission products. In order to improve sensitivity, a high efficiency sample introduction system was coupled to the employed high resolution ICP-OES instrument. The ten most sensitive emission wavelengths of Nd were investigated systematically, all of them yielding detection limits (LODs) of less than 1 μg kg−1. The highest sensitivity and the best LOD of 0.3 μg kg−1 were obtained at the emission lines λ = 401.225 nm and λ = 430.358 nm. Compared to previous studies this LOD is more than one order of magnitude lower while sample consumption (∼0.3 mL min−1) is less than one third of the volume normally required for such analysis. In terms of radioactive samples these improved analytical figures of merit denote a considerably lower dose to the ICP-OES operator and less radioactive waste. Considering sensitivity, potential spectral interferences and stability of the spectral background, the four emission lines at λ = 401.225 nm, λ = 406.109 nm, λ = 410.946 nm and λ = 430.358 nm proved to be most useful for the reliable determination of Nd. In the absence of matrix matched reference materials having a certified Nd concentration, the accuracy of Nd ICP-OES analysis was ascertained by quantification of Nd using both external calibration and the standard addition approach. In addition, sector field ICP-MS analysis of the Nd elemental concentration was also possible without any separation step as the Nd isotopic composition of the spent fuel was well characterised in previous analyses. This new series of ICP-MS analyses was based on the interference-free isotopes 143Nd, 144Nd (a small 144Ce correction was almost negligible), 145Nd and 146Nd, which are also the four main isotopes in fission Nd. The relative isotopic results obtained using sector field ICP-MS confirmed the previously determined Nd isotopic composition. The repeated Nd concentration analysis of the dissolved spent fuel sample applying the developed ICP-OES and ICP-MS procedures gave results that overlapped within their standard deviations, underpinning the reliability of both experimental approaches.

Determination of uranium concentration in an ore sample using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) has been recognized as a promising technique for analyzing sensitive nuclear materials such as uranium, plutonium, and curium in a high-radiation environment, especially since the implementation of IAEA (International Atomic Energy Agency) safeguards. The uranium spectra of ore samples were quantitatively analyzed prior to analyzing sensitive materials in the nuclear industry. The purpose of this experiment is to extract quantitative information about the uranium in a uranium ore using a standard addition approach. The uranium ore samples containing different concentrations of U were prepared by mixing raw ore powder with natural uranium oxide powders. Calibration sets of 0.2, 0.4, 0.6, 0.8 and 1.0wt.% uranium concentrations within the uranium ore sample were achieved. A pulsed and Q-switched Nd:YAG laser at a wavelength of 532nm was used as a light source. An echelle spectrometer that covers a 190–420nm wavelength range is used to generate a calibration curve and determine the detection limit of uranium in the ore matrix. The neutral atomic-emission peak at a wavelength of 356.659nm indicated a detection limit of ~158ppm for uranium, and the uranium concentration was determined in a raw ore sample that has an unknown quantity of uranium.

Serum levels of N-acetyl-aspartate in migraine and tension-type headache.

Serum levels of N-acetyl-aspartate (NAA) may be considered a useful marker of neuronal functioning. We aimed to measure serum NAA in cohorts of migraine and tension-type headache patients versus controls, performing correlations with main clinical features. A total of 147 migraine patients (including migraine without aura, with aura and chronic migraine), 65 tension-type headache (including chronic and frequent episodic tension-type headache) and 34 sex- and age-matched controls were selected. Serum was stored at −80 °C. Quantification of NAA was achieved by the standard addition approach and analysis was performed with liquid-chromatography–mass-spectrometry (LC/MS) technique. The NAA levels were significantly decreased in migraine group (0.065 ± 0.019 mol/L), compared with both tension-type headache patients (0.078 ± 0.016 mol/L) and controls (0.085 ± 0.013 mol/L). Control subjects were significantly different from migraine with and without aura and chronic migraine, who differed significantly from episodic and chronic tension-type headache. Migraine with aura patients showed lower NAA levels when compared to all the other headache subtypes, including migraine without aura and chronic migraine. In the migraine group, no significant correlation was found between NAA serum levels, and headache frequency, allodynia and interval from the last and the next attack. The low NAA in the serum may be a sign of neuronal dysfunction predisposing to migraine, probably based on reduced mitochondria function.

Determination of non-halogenated, chlorinated and brominated organophosphate flame retardants in herring gull eggs based on liquid chromatography–tandem quadrupole mass spectrometry

Numerous triester organophosphate flame retardants (OPFRs) have been used for several decades and continue to be used in a variety of commercial products. We developed a sensitive quantitative method for the analysis of, seven non-halogenated, three chlorinated and two brominated OPFRs of known or possible environmental relevance in herring gull eggs. This method is based on a simple two-step sample extraction followed by liquid chromatography-electrospray ionization(+)-tandem mass spectrometry. Instrumental detection limits and method limits of quantification (MLOQs) among the 12 OPFRs ranged from 0.01 to 0.12 ng/mL and 0.06 to 0.20 ng/g, respectively. The mean OPFR recovery efficiencies of replicate analyses (n=6) were very quantitative and ranged from 89% to 104%, with the two brominated OPFRs being somewhat lower but reproducible, i.e., 67% and 72%, respectively. Essentially negligible matrix effects were indicated by a standard addition approach that revealed mean percent signal recoveries (n=5 replicates) of 89-106% for most OPFRs. In the analysis of n=13 herring gull eggs from the Channel-Shelter Island colony (Lake Huron), tris(2-chloroisopropyl) phosphate (<MLOQ - 4.1 ng/g wet weight, ww), tris(2-chloroethyl) phosphate (<MLOQ - 0.6 ng/g ww) and tris(2-butoxyethyl) phosphate (<MLOQ - 2.2 ng/g ww) were detected and/or quantified.

Determination of organic acids in fruits and vegetables by liquid chromatography with tandem-mass spectrometry

A method using liquid chromatography coupled to tandem-mass spectrometry (LC–MS/MS) with triple quadrupole in selective reaction monitoring mode was developed to determine organic acids (glutamic, tartaric, quinic, malonic, malic, shikimic, α-ketoglutaric, pyruvic, citric, succinic and fumaric acids) in fruits (melon, grape, peach, orange, lemon) and vegetables (green and red pepper, tomato, lettuce and lamb’s lettuce). The negative ion mode of ESI was used. All the validation parameters were found to be within the range of acceptance for all the compounds. Different matrix effects were observed in the studied vegetables and samples were quantified by the standard additions approach. The main advantages of this method are its selectivity, which is one of the main weaknesses of most methods when analysing organic acid in complex matrices, and its simplicity since little sample preparation is needed.

Simultaneous determination of ascorbic and dehydroascorbic acids in vegetables and fruits by liquid chromatography with tandem-mass spectrometry

This work describes an analytical method using liquid chromatography coupled with tandem-mass spectrometry (LC–MS/MS) with triple quadrupole in selective reaction monitoring mode for the simultaneous determination of ascorbic acid (AA) and dehydroascorbic acid (DHAA) in pepper, tomato, orange and lemon. The negative ion mode of ESI and MS/MS transitions of m/z 173→143 and m/z 173→71 were used for AA and m/z 175→115 and m/z 175→87 for DHAA. All the validation parameters were found to be within the range of acceptance for both compounds. Different matrix effects were observed in the studied vegetables and samples were quantified by the standard addition approach. The proposed method was suitable for simultaneously determining AA and DHAA with no need for oxidation/reduction or derivatisation steps. The main advantages of this method are its simplicity (little sample preparation), speed (total analysis time does not exceed 5min) and excellent sensitivity (limits of detection (LODs) of 13 and 11ng/ml for AA and DHAA, respectively).

Quantitative determination of ZrC in new ceramic materials by Fourier transform infrared spectroscopy

Zirconium carbide-based biomorphic ceramics have been manufactured by vacuum infiltration of zirconium-oxychloride (ZrOCl 2·8H 2O) sol into natural wood. After vacuum-assisted infiltration, the specimens were dried in air and pyrolysed at 800 °C in Ar-atmosphere. The infiltration and drying process were repeated up to four times. Finally, the specimens were hold at 1550 °C in a vacuum furnace to form ZrC. The results of the process of synthesis have been studied using scanning electron microscopy (SEM). For evaluating the yield of the synthesis, a new method by Fourier transform infrared spectrometry (FTIR) has been developed for the direct determination of ZrC by absorbance measurements in KBr pellets. The procedure was based on the use of the ratio between the absorbance of the characteristic band of zirconium carbide and those of an oxalate internal standard added to samples. A multivariate calibration strategy based on inverse least squares and the standard addition approach was employed for quantification. The results obtained for all ZrC-ceramics studied were satisfactorily compared with those obtained by X-ray diffractometry (XRD). The proposed method was also applied to the analysis of synthetic samples prepared by mixing pyrolyzed wood with ZrC, the results indicated good recovery in all instances.

Quantification of 2-Acetyl-1-pyrroline and Other Rice Aroma Volatiles Among Indian Scented Rice Cultivars by HS-SPME/GC-FID

A method for quantitative determination of 2-Acetyl-1-pyrroline (2AP) and other aroma volatiles using HS-solid phase micro extraction (SPME)/GC-FID in scented rice has been developed. Extraction at 80 °C for 30 min pre-incubation followed by 20-min adsorption from 1 g rice containing 300 μl of odour-free water were the optimum conditions for quantification. Calibration curves of aroma volatiles were obtained by standard addition approach. The optimised conditions were employed for quantitative analysis in 33 scented and two non-scented rice samples. Highest amount of 2AP was recorded in Indrayani Brand 2 (0.552 ppm), followed by Kamod (0.418 ppm) and Basmati Brand 5 (0.411 ppm). Rice types (Basmati, Ambemohar, Kolam, Indrayani and local) significantly contributed to the variation in 2AP, hexanal, nonanal, decanal, benzyl alcohol, vanillin, guaiacol and indole. The method developed suffices the need of rapid and reliable method for quantification of 2AP and other aroma-related volatiles from aromatic rice cultivars.

The accuracy of δ11B measurements of foraminifers

Values of δ 11B reported in the literature for Holocene samples of the same foraminiferal species show large variability (6‰) relative to cited precision (< 1‰). This is indicative of significant inter-laboratory biases and raises concerns about the accuracy of foraminiferal proxy pH records. To investigate this problem we have measured the δ 11B of modern ocean carbonates using several different analytical procedures. We have used total evaporation negative thermal ionisation mass spectrometry (TE-NTIMS), with various sample preparation and loading procedures and multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The δ 11B of pure boric acid solutions measured by TE-NTIMS and MC-ICPMS agree well, demonstrating no fundamental biases between the techniques. Yet the δ 11B values measured by TE-NTIMS for non-foraminiferal carbonates are about 2‰ lighter than those by MC-ICPMS whereas foraminifers measured by the same standard TE-NTIMS procedure are 2 to 6‰ heavier than those by MC-ICPMS. Significantly, we found that foraminiferal samples kept in acidic solution over several months yielded lower δ 11B values (up to 5‰ lower) and better reproducibility when re-measured by TE-NTIMS. We infer that organic material, released on foraminiferal dissolution, causes biases in NTIMS measurements. No residual organics should be present in the MC-ICPMS measurements as matrix is separated from sample before analysis. Moreover we demonstrate by standard addition the absence of any matrix influence in the MC-ICPMS procedure beyond the inherent uncertainties in the standard addition approach (∼ ± 0.35‰ 2sigma). Degradation of the inferred organic residue, either by long term storage in acidic solution or by loading samples in 30% H 2O 2, reduces but does not totally remove the (variable) bias between TE-NTIMS and MC-ICPMS δ 11B measurements. Despite these problems, careful analysis of similar samples by NTIMS may permit data to be obtained with consistent relative differences that still yield valuable proxy records, but there is clearly considerable potential for inaccuracies to result in such an approach from hard to detect changes in matrix.

Characterisation of steroids in wooden crates of veal calves by accelerated solvent extraction (ASE®) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-QqQ-MS-MS)

Illegal steroid administration to enhance growth performance in veal calves has long been, and still is, a serious issue facing regulatory agencies. Over the last years, stating undisputable markers of illegal treatment has become complex because of the endogenous origin of several anabolic steroids. Knowledge on the origin of an analyte is therefore of paramount importance. The present study shows the presence of steroid analytes in wooden crates used for housing veal calves. For this purpose, an analytical procedure using accelerated solvent extraction (ASE(R)), solid-phase extraction (SPE) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-MS-MS) is developed for the characterisation of androstadienedione (ADD), boldenone (bBol), androstenedione (AED), beta-testosterone (bT), alpha-testosterone (aT), progesterone (P) and 17alpha-hydroxy-progesterone (OH-P) in wood samples. In samples of wooden crates used for housing veal calves, ADD, AED, aT and P could be identified. Using the standard addition approach concentrations of these analytes were determined ranging from 20 +/- 4 ppb to 32 +/- 4 ppb for ADD, from 19 +/- 5 ppb to 44 +/- 17 ppb for AED, from 11 +/- 6 ppb to 30 +/- 2 ppb for aT and from 14 +/- 1 ppb to 42 +/- 27 ppb for P, depending on the sample type. As exposure of veal calves to steroid hormones in their housing facilities might complicate decision-making on illegal hormone administration, inequitable slaughter of animals remains possible. Therefore, complete prohibition of wooden calf accommodation should be considered.