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Mathijssen J, Rozema A, Hiemstra M, Jansen M, van Oers J. Stability of and change in substance use risk personality: Gender differences and smoking cigarettes among early adolescents. Addict Behav Rep 2021; 14:100360. [PMID: 34159249 PMCID: PMC8196044 DOI: 10.1016/j.abrep.2021.100360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 03/17/2021] [Accepted: 06/01/2021] [Indexed: 12/05/2022] Open
Abstract
OBJECTIVE Adolescents show a steadily increasing inclination toward health risk behaviors, including smoking cigarettes. There is ample evidence that personality traits are related to smoking behavior. However, less is known about the stability of and change in these personality traits during early adolescence and whether smoking behavior affects the developmental trajectories. Moreover, less is known about the influence of gender on the course of personality. METHOD Longitudinal data of three waves were used from 1121 early adolescents. To measure personality, the Substance Use Risk Profile Scale was used. Individual growth curve models were conducted to measure the stability, mean-level change and individual differences in change for personality. RESULTS Stability of personality was moderate for boys and ranged from moderate to high for girls. On average early adolescents became more impulsive and more sensation seeking over a period of 18 months. Furthermore, hopelessness for girls increased and the increase in sensation seeking was higher for girls than for boys. Third, smoking behavior was related to all personality traits, indicating that smoking adolescents are more anxious, hopeless, impulsive and sensation seeking than non-smoking adolescents. CONCLUSIONS Our results are in line with the disruption hypothesis, i.e., during early adolescence there is a dip in personality maturity. There are clear differences between girls and boys in stability of and change in personality traits. Besides, although smoking behavior is related to personality, the change in personality is probably related to other variables.
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Affiliation(s)
- J.J.P Mathijssen
- Tilburg School of Social and Behavioral Sciences, Department Tranzo, Tilburg University, the Netherlands
| | - A.D. Rozema
- Tilburg School of Social and Behavioral Sciences, Department Tranzo, Tilburg University, the Netherlands
| | - M. Hiemstra
- Tilburg School of Social and Behavioral Sciences, Department Tranzo, Tilburg University, the Netherlands
| | - M.W.J. Jansen
- Academic Collaborative Centre for Public Health Limburg, Public Health Service South Limburg (GGD ZL), Heerlen, the Netherlands
- Department of Health Services Research, CAPHRI Care and Public Health Research Institute, Maastricht University, Maastricht, the Netherlands
| | - J.A.M. van Oers
- Tilburg School of Social and Behavioral Sciences, Department Tranzo, Tilburg University, the Netherlands
- Ministry of Health and Welfare, Den Haag, the Netherlands
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De Kok A, Hiemstra M. Optimization, Automation, and Validation of the Solid-Phase Extraction Cleanup and On-Line Liquid Chromatographic Determination of N-Methylcarbamate Pesticides in Fruits and Vegetables. J AOAC Int 2020. [DOI: 10.1093/jaoac/75.6.1063] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A fully automated liquid chromatographic (LC) method was developed for the determination of 21 N-methylcarbamates and 12 of their metabolites. Our previously developed solid-phase extraction (SPE) cleanup method can now be performed using an automated SPE cleanup apparatus. The cleaned-up extract is injected on-line into the LC carbamate analysis system, which is based on a reversed- phase LC separation, postcolumn hydrolysis of the carbamates on a solid-phase catalyst, reaction of the methylamine formed with ophthalaldehyde reagent, and fluorescence detection of the derivatives. The optimized method was evaluated. Recovery and repeatability data were collected for 13 representative carbamates and 12 metabolites on 12 different food product types. The reliability of the method in routine analysis of fruit and vegetable samples is demonstrated. Registration of the analytical results of control samples in Shewhart charts during a year of routine analysis has demonstrated the excellent performance of this complete method. The limits of determination are in the 5-50 μg/kg (ppb) range. Sample throughput is about 20 per 24 h. Data are presented on real residues of N-methylcarbamates found in fruits and vegetables during 4 years of routinely applying this multiresidue method
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Affiliation(s)
- André De Kok
- Inspectorate for Health Protection/Food Inspection Service, Pesticide Analysis Department, Burgpoelwaard 6,1824 DW Alkmaar, The Netherlands
| | - Maurice Hiemstra
- Inspectorate for Health Protection/Food Inspection Service, Pesticide Analysis Department, Burgpoelwaard 6,1824 DW Alkmaar, The Netherlands
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Hiemstra M, Toonen A, Kok AD. Determination of Benzoylphenylurea Insecticides in Pome Fruit and Fruiting Vegetables by Liquid Chromatography with Diode Array Detection and Residue Data Obtained in the Dutch National Monitoring Program. J AOAC Int 2020. [DOI: 10.1093/jaoac/82.5.1198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Liquid chromatography (LC) with diode array detection was used to screen for residues of the benzoylphenylurea (BPU) insecticides diflubenzuron, teflubenzuron, triflumuron, hexaflumuron, lufenuron, chlorfluazuron, flufenoxuron, and flucycloxuron in pome fruit and fruiting vegetables. The general sample preparation and extraction method for our gas chromatography (GC) and LC multiresidue methods scheme was used as a starting point. Crop samples were extracted with acetone and partitioned into di-chloromethane-petroleum ether. Solid-Phase extraction on aminopropyl-bonded silica cartridges was used to separate the BPU insecticides from major interfering sample components. LC separations were performed on a reversed-phase column, with an acetonitrile-water gradient as mobile phase. A diode array detector was used to monitor the insecticides at 260 nm and to acquire spectral information for additional confirmation. Recoveries and repeatability data were collected for 7 benzoylphenylurea insecticides in mushroom, Chinese cabbage, apple, and cucumber samples representing different commodity groups at one spike level. The limits of detection ranged from 20 to 50 μg/kg for all BPU insecticides studied and is dependent on the matrix-pesticide combination. A confirmation method for BPU insecticides based on GC-mass spectrometry (ion-trap detector) of the characteristic degradation products is also reported. Residues of BPU insecticides in pome fruit and fruiting vegetables found during our Dutch pesticide residue monitoring program in 1995-1998 are presented.
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Affiliation(s)
- Maurice Hiemstra
- Inspectorate for Health Protection, Department of Pesticide Analysis, Alkmaar, The Netherlands
| | - Arnold Toonen
- Inspectorate for Health Protection, Department of Pesticide Analysis, Alkmaar, The Netherlands
| | - André De Kok
- Inspectorate for Health Protection, Department of Pesticide Analysis, Alkmaar, The Netherlands
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Hiemstra M, Joosten JA, de Kok A. Fully Automated Solid-Phase Extraction Cleanup and On-Line Liquid Chromatographic Determination of Benzimidazole Fungicides in Fruit and Vegetables. J AOAC Int 2020. [DOI: 10.1093/jaoac/78.5.1267] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
A liquid chromatographic (LC) method using fully automated solid-phase extraction (SPE) sample cleanup and on-line LC analysis was developed for determination of the benzimidazole fungicides car-bendazim and thiabendazole in various crops. Preparation of food samples involved extraction with acetone followed by solvent partitioning with dichloromethane–petroleum ether to draw the analytes into the organic phase. The laborious liquid–liquid partitioning cleanup procedure described in the literature was replaced with a fast SPE cleanup using diol-bonded silica cartridges. Automation of the total procedure was achieved by using a commercially available SPE cleanup apparatus (ASPEC). The cleaned-up extract was injected on-line into an LC system with UV and fluorescence detection in tandem. Chromatographic separations were performed with a methanol–phosphate buffer mobile phase (pH = 7) and different polymeric stationary phases. The polymer-based columns performed better than silica-based columns in separating benzimidazole fungicides, and different columns were compared. Results of validation studies with fortified lettuce and citrus fruit are presented. Shewhart control charts of analytical results of control samples demonstrated good performance of the complete system. Sample throughput (extraction, automated SPE, and on-line LC analysis) was about 50 samples per 24 h. Residues of carbendazim and thiabendazole found during our pesticide residue monitoring program in 1992–1994 are reported.
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Affiliation(s)
- Maurice Hiemstra
- Inspectorate for Health Protection, Food Inspection Service, Department of Pesticide Analysis, Burgpoelwaard 6, 1824 DW Alkmaar, The Netherlands
| | - Jeannette A Joosten
- Inspectorate for Health Protection, Food Inspection Service, Department of Pesticide Analysis, Burgpoelwaard 6, 1824 DW Alkmaar, The Netherlands
| | - Andre de Kok
- Inspectorate for Health Protection, Food Inspection Service, Department of Pesticide Analysis, Burgpoelwaard 6, 1824 DW Alkmaar, The Netherlands
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Lehotay SJ, O’Neil M, Tully J, García AV, Contreras M, Mol H, Heinke V, Anspach T, Lach G, Fussell R, Mastovska K, Poulsen ME, Brown A, Hammack W, Cook JM, Alder L, Lindtner K, Vila MG, Hopper M, de Kok A, Hiemstra M, Schenck F, Williams A, Parker A. Determination of Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate: Collaborative Study. J AOAC Int 2019. [DOI: 10.1093/jaoac/90.2.485] [Citation(s) in RCA: 500] [Impact Index Per Article: 100.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A collaborative study was conducted to determine multiple pesticide residues in fruits and vegetables using a quick, simple, inexpensive, and effective sample preparation method followed by concurrent analysis with gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). For short, the method is known as QuEChERS, which stands for quick, easy, cheap, effective, rugged, and safe. Twenty representative pesticides were fortified in 3 matrixes (grapes, lettuces, and oranges) at 3 duplicate levels unknown to the collaborators ranging from 10 to 1000 ng/g. Additionally, 8 incurred pesticide residues were determined. Thirteen laboratories from 7 countries provided results in the study, and a variety of different instruments were used by collaborators. The QuEChERS procedure simply entails 3 main steps: (1) a 15 g homogenized sample is weighed into a 50 mL centrifuge tube to which 15 mL acetonitrile containing 1 HOAc is added along with 6 g MgSO4 and 1.5 g NaOAc, and the tube is shaken and centrifuged; (2) a portion of the extract is mixed with 3 + 1 (w/w) MgSO4primary secondary amine sorbent (200 mg/mL extract) and centrifuged; and (3) the final extract is analyzed by GC/MS and LC/MS/MS. To detect residues <10 ng/g in GC/MS, large-volume injection of 8 L is typically needed, or the extract can be concentrated to 4 g/mL in toluene, in which case 2 L splitless injection is used. In the study, the averaged results for data from 713 laboratories (not using internal standardization) for the 18 blind duplicates at the 9 spiking levels in the 3 matrixes are as follows [%recovery and reproducibility relative standard deviation (RSDR, %)]: atrazine, 92 (18); azoxystrobin, 93 (15); bifenthrin, 90 (16); carbaryl, 96 (20); chlorothalonil, 70 (34); chlorpyrifos, 89 (25); cyprodinil, 89 (19); o, p-DDD, 89 (18); dichlorvos, 82 (21); endosulfan sulfate, 80 (27); imazalil, 77 (33); imidacloprid, 96 (16); linuron, 89 (19);methamidophos, 87 (17); methomyl, 96 (17); procymidone, 91 (20); pymetrozine, 69 (19); tebuconazole, 89 (15); tolylfluanid (in grapes and oranges), 68 (33); and trifluralin, 85 (20). For incurred pesticides, kresoxim-methyl (9.2 3.2 ng/g) and cyprodinil (112 18) were found in the grapes; permethrins (112 41), -cyhalothrin (58 11), and imidacloprid (12 2) were determined in the lettuces; and ethion (198 36), thiabendazole (53 8), and imazalil (13 4) were determined in the oranges. Chlorpyrifosmethyl (200 ng/g) was used as a quality control standard added during sample homogenization and yielded 86% recovery and 19% RSDR. Intralaboratory repeatabilities for the method averaged 9.8% RSD for all analytes. The results demonstrate that the method is fit-for- purpose to monitor many pesticide residues in fruits and vegetables, and the Study Director recommends that it be adopted Official First Action.
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Affiliation(s)
- Steven J Lehotay
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Ln, Wyndmoor, PA 19038
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Lehotay SJ, Kok AD, Hiemstra M, Bodegraven PV. Validation of a Fast and Easy Method for the Determination of Residues from 229 Pesticides in Fruits and Vegetables Using Gas and Liquid Chromatography and Mass Spectrometric Detection. J AOAC Int 2019. [DOI: 10.1093/jaoac/88.2.595] [Citation(s) in RCA: 447] [Impact Index Per Article: 89.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10–100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid–liquid partitioning step performed by adding 6 g anhydrous MgSO4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO4, which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70–120% (90–110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods.
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Affiliation(s)
- Steven J Lehotay
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Ln, Wyndmoor, PA 19038
| | - André de Kok
- Dutch Food and Consumer Products Safety Authority–Food Inspection Service (VWA-KvW), Region North West, Research and Development Department, Pesticide Analysis Group, Hoogte Kadijk 401, 1018 BK Amsterdam, The Netherlands
| | - Maurice Hiemstra
- Dutch Food and Consumer Products Safety Authority–Food Inspection Service (VWA-KvW), Region North West, Research and Development Department, Pesticide Analysis Group, Hoogte Kadijk 401, 1018 BK Amsterdam, The Netherlands
| | - Peter van Bodegraven
- Dutch Food and Consumer Products Safety Authority–Food Inspection Service (VWA-KvW), Region North West, Research and Development Department, Pesticide Analysis Group, Hoogte Kadijk 401, 1018 BK Amsterdam, The Netherlands
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Alder L, Startin JR, Alonso S, Anspach T, Brewin S, Broekaert C, Christiansen A, DeKok A, Frase U, Fresvig M, Hemmerling C, Hermansson E, Hiemstra M, Hogendoorn E, Kolb J, Kombal R, Melk C, Polonji B, Quirijns JK, Ross L, Saint-Joly C, Scherbaum E, van Damme D, Welter A, Wüst B. Determination of Chlormequat and Mepiquat in Foods by Liquid Chromatography/Mass Spectrometry or Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Study. J AOAC Int 2019. [DOI: 10.1093/jaoac/88.6.1762] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Interlaboratory validation studies have been performed on 2 methods for the determination of chlormequat (CLQ) and mepiquat (MPQ). Both methods used identical extraction procedures and stable isotope internal standardization but differed in the use of liquid chromatography/mass spectrometry (LC/MS) or LC/tandem mass spectrometry (LC/MS/MS) for the determination, the amount of internal standard used, and the expected limit of detection. After addition of deuterated internal standards, CLQ and MPQ were extracted with methanol–water and determined by LC/MS or LC/MS/MS with positive electrospray ionization. Eight European laboratories participated in the LC/MS method study, analyzing mushroom, pear, wheat flour, and fruit puree with residues of CLQ in the range 0.040–1.19 mg/kg and of MPQ in the range 0.041–0.39 mg/kg. For CLQ, the Horwitz ratio (HoRat) values for individual test materials/levels were in the range 0.85–1.13 with amean of 1.00, showing good method performance. For MPQ, the Ho values for mushroom, pear (both levels), and wheat flour were in the range 0.83–0.94, again indicating good method performance. For the determination of MPQ in infant food (fruit puree) at 0.041 mg/kg, the Ho was 1.7 when a value of 0 reported by one participant was excluded. In the LC/MS/MS study, in which 11 laboratories participated, a separate sample set was analyzed with residues of CLQ in the range 0.007–1.03 mg/kg and of MPQ in the range 0.008–0.72 mg/kg. Ho values for CLQ were in the range 0.27–1.36 and for MPQ in the range 0.51–2.10, all corresponding to acceptable method performance.
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Affiliation(s)
- Lutz Alder
- Federal Institute for Risk Assessment, D-14191 Berlin, Germany
| | - James R Startin
- Central Science Laboratory, Sand Hutton, York, YO41 1LZ, United Kingdom
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Mollink J, Hiemstra M, Miller KL, Huszar IN, Jenkinson M, Raaphorst J, Wiesmann M, Ansorge O, Pallebage-Gamarallage M, van Cappellen van Walsum AM. White matter changes in the perforant path area in patients with amyotrophic lateral sclerosis. Neuropathol Appl Neurobiol 2019; 45:570-585. [PMID: 31002412 PMCID: PMC6852107 DOI: 10.1111/nan.12555] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 04/15/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that white matter degeneration of the perforant path - as part of the Papez circuit - is a key feature of amyotrophic lateral sclerosis (ALS), even in the absence of frontotemporal dementia (FTD) or deposition of pTDP-43 inclusions in hippocampal granule cells. METHODS We used diffusion Magnetic Resonance Imaging (dMRI), polarized light imaging (PLI) and immunohistochemical analysis of post mortem hippocampus specimens from controls (n = 5) and ALS patients (n = 14) to study white matter degeneration in the perforant path. RESULTS diffusion Magnetic Resonance Imaging demonstrated a decrease in fractional anisotropy (P = 0.01) and an increase in mean diffusivity (P = 0.01) in the perforant path in ALS compared to controls. PLI-myelin density was lower in ALS (P = 0.05) and correlated with fractional anisotropy (r = 0.52, P = 0.03). These results were confirmed by immunohistochemistry; both myelin (proteolipid protein, P = 0.03) and neurofilaments (SMI-312, P = 0.02) were lower in ALS. Two out of the fourteen ALS cases showed pTDP-43 pathology in the dentate gyrus, but with comparable myelination levels in the perforant path to other ALS cases. CONCLUSION We conclude that degeneration of the perforant path occurs in ALS patients and that this may occur before, or independent of, pTDP-43 aggregation in the dentate gyrus of the hippocampus. Future research should focus on correlating the degree of cognitive decline to the amount of white matter atrophy in the perforant path.
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Affiliation(s)
- J Mollink
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - M Hiemstra
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - K L Miller
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - I N Huszar
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - M Jenkinson
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - J Raaphorst
- Department of Neurology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - M Wiesmann
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - O Ansorge
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - A M van Cappellen van Walsum
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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Hiemstra M, Otten R, van Schayck OCP, Engels RCME. P2-415 Smoking-specific communication and children's smoking behaviour: an extension of the theory of planned behaviour. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976l.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Pizzutti IR, de Kok A, Hiemstra M, Wickert C, Prestes OD. Method validation and comparison of acetonitrile and acetone extraction for the analysis of 169 pesticides in soya grain by liquid chromatography-tandem mass spectrometry. J Chromatogr A 2009; 1216:4539-52. [PMID: 19375710 DOI: 10.1016/j.chroma.2009.03.064] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 03/23/2009] [Accepted: 03/24/2009] [Indexed: 11/25/2022]
Abstract
An acetonitrile-based extraction method for the analysis of 169 pesticides in soya grain, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive and negative electrospray ionization (ESI) mode, has been optimized and validated. This method has been compared with our earlier published acetone-based extraction method, as part of a comprehensive study of both extraction methods, in combination with various gas chromatography-(tandem) mass spectrometry [GC-MS(/MS)] and LC-MS/MS techniques, using different detection modes. Linearity of calibration curves, instrument limits of detection (LODs) and matrix effects were evaluated by preparing standards in solvent and in the two soya matrix extracts from acetone and acetonitrile extractions, at seven levels, with six replicate injections per level. Limits of detection were calculated based on practically realized repeatability relative standard deviations (RSDs), rather than based on (extrapolated) signal/noise ratios. Accuracies (as % recoveries), precision (as repeatability of recovery experiments) and method limits of quantification (LOQs) were compared. The acetonitrile method consists of the extraction of a 2-g sample with 20 mL of acetonitrile (containing 1% acetic acid), followed by a partitioning step with magnesium sulphate and a subsequent buffering step with sodium acetate. After mixing an aliquot with methanol, the extract can be injected directly into the LC-MS/MS system, without any cleanup. Cleanup hardly improved selectivity and appeared to have minor changes of the matrix effect, as was earlier noticed for the acetone method. Good linearity of the calibration curves was obtained over the range from 0.1 or 0.25 to 10 ng mL(-1), with r(2)>or=0.99. Instrument LOD values generally varied from 0.1 to 0.25 ng mL(-1), for both methods. Matrix effects were not significant or negligible for nearly all pesticides. Recoveries were in the range 70-120%, with RSD
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Affiliation(s)
- Ionara R Pizzutti
- Chemistry Department, Federal University of Santa Maria, Center of Research and Analysis of Residues and Contaminants, Santa Maria, RS, Brazil.
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Hiemstra M, de Kok A. Comprehensive multi-residue method for the target analysis of pesticides in crops using liquid chromatography–tandem mass spectrometry. J Chromatogr A 2007; 1154:3-25. [PMID: 17442324 DOI: 10.1016/j.chroma.2007.03.123] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 03/16/2007] [Accepted: 03/21/2007] [Indexed: 11/25/2022]
Abstract
A liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) multi-residue method for the simultaneous target analysis of a wide range of pesticides and metabolites in fruit, vegetables and cereals has been developed. Gradient elution has been used in conjunction with positive mode electrospray ionization tandem mass spectrometry to detect up to 171 pesticides and/or metabolites in different crop matrices using a single chromatographic run. Pesticide residues were extracted/partitioned from the samples with acetone/dichloromethane/light petroleum. The analytical performance was demonstrated by the analysis of extracts from lettuce, orange, apple, cabbage, grape and wheat flour, spiked at three concentration levels ranging from 0.01 to 0.10 mg/kg for each pesticide and/or metabolite. In general, recoveries ranging from 70 to 110%, with relative standard deviations better than 15%, were obtained. The recovery and repeatability data are in good accordance with EU guidelines for pesticide residue analysis. The limit of quantification for all targeted pesticides and metabolites tested was 0.01 mg/kg. The selectivity and robustness of the LC-MS/MS method was demonstrated by a 1-year comparison of its analytical results with those obtained from our validated GC and LC multi-residue methods applied to more than 3500 routine samples. The validated LC-MS/MS method has been implemented in our analytical scheme since 2004, replacing four of the conventional detection methods, i.e. GC-flame-photometric detection (acephate, methamidophos, etc.), GC-nitrogen-phosphorus detection, LC-UV detection (carbendazim, thiabendazole, imazalil and prochloraz) and LC-fluorescence detection (N-methylcarbamate pesticides). During a 3-year period, the LC-MS/MS method has been applied to the analyses of more than 12,000 samples.
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Affiliation(s)
- Maurice Hiemstra
- VWA-Food and Consumer Product Safety Authority, Chemistry Laboratory-R&D, Pesticide Analysis Group, Hoogte Kadijk 401, 1018 BK Amsterdam, The Netherlands.
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Pizzutti IR, de Kok A, Zanella R, Adaime MB, Hiemstra M, Wickert C, Prestes OD. Method validation for the analysis of 169 pesticides in soya grain, without clean up, by liquid chromatography-tandem mass spectrometry using positive and negative electrospray ionization. J Chromatogr A 2007; 1142:123-36. [PMID: 17222861 DOI: 10.1016/j.chroma.2006.12.030] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/04/2006] [Accepted: 12/05/2006] [Indexed: 11/23/2022]
Abstract
Part of a comprehensive study on the comparison of different extraction methods, GC-MS(/MS) and LC-MS/MS detection methods and modes, for the analysis of soya samples is described in this paper. The validation of an acetone-based extraction method for analysis of 169 pesticides in soya, using LC-MS/MS positive and negative electrospray ionisation (ESI) mode, is reported. Samples (5 g) were soaked with 10 g water and subsequently extracted with 100 mL of a mixture of acetone, dichloromethane and light petroleum (1:1:1), in the presence of 15 g anhydrous sodium sulphate. After centrifugation, aliquots of the extract were evaporated and reconstituted in 1.0 mL of methanol, before direct injection of the final extract (corresponding with 0.05 g soya mL(-1)) into the LC-MS/MS system. Linearity, r(2) of calibration curves, instrument limit of detection/quantitation (LOD/LOQ) and matrix effect were evaluated, based on seven concentrations measured in 6-fold. Good linearity (at least r(2)> or =0.99) of the calibration curves was obtained over the range from 0.1 or 0.25 to 10.0 ng mL(-1), corresponding with pesticide concentrations in soya bean extract of 2 or 5-200 microg kg(-1). Instrument LOD values generally were 0.1 or 0.25 ng mL(-1). Matrix effects were negligible for approximately 90% of the pesticides. The accuracy, precision and method LOQ were determined via recovery experiments, spiking soya at 10, 50, 100 microg kg(-1), six replicates per level. In both ESI modes, method LOQ values were mostly 10 or 50 microg kg(-1) and more than 70% of pesticides analysed by each mode met the acceptability criteria of recovery (70-120%) and RSD (< or =20%), at one or more of the three levels studied. A fast, easy and efficient method with acceptable performance was achieved for a difficult matrix as soya, without cleanup.
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Affiliation(s)
- Ionara R Pizzutti
- Federal University of Santa Maria, Chemistry Department, Laboratory of Pesticide Residues Analysis (LARP), Santa Maria, RS, Brazil
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Lehotay SJ, de Kok A, Hiemstra M, Van Bodegraven P. Validation of a fast and easy method for the determination of residues from 229 pesticides in fruits and vegetables using gas and liquid chromatography and mass spectrometric detection. J AOAC Int 2005; 88:595-614. [PMID: 15859089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10-100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid-liquid partitioning step performed by adding 6 g anhydrous MgSO4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO4, which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70-120% (90-110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods.
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Affiliation(s)
- Steven J Lehotay
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Ln, Wyndmoor, PA 19038, USA.
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Konings EJM, Baars AJ, van Klaveren JD, Spanjer MC, Rensen PM, Hiemstra M, van Kooij JA, Peters PWJ. Acrylamide exposure from foods of the Dutch population and an assessment of the consequent risks. Food Chem Toxicol 2003; 41:1569-79. [PMID: 12963010 DOI: 10.1016/s0278-6915(03)00187-x] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
At the end of April 2002, the Swedish Food Administration reported the presence of acrylamide in heat treated food products. Acrylamide has been shown to be toxic and carcinogenic in animals, and has been classified by the WHO/IARC among others as 'probably carcinogenic for humans'. The purposes of this study were firstly to analyse acrylamide contents of the most important foods contributing to such exposure, secondly, to estimate the acrylamide exposure in a representative sample of the Dutch population, and thirdly to estimate the public health risks of this consumption. We analysed the acrylamide content of foods with an LC-MS-MS method. The results were then used to estimate the acrylamide exposure of consumers who participated in the National Food Consumption Survey (NFCS) in 1998 (n=6250). The exposure was estimated using the probabilistic approach for the total Dutch population and several age groups. For 344 food products, acrylamide amounts ranged from <30 to 3100 microg/kg. Foods with the highest mean acrylamide amounts were potato crisps (1249 microg/kg), chips (deep-fried) (351 microg/kg), cocktail snacks (1060 microg/kg), and gingerbread (890 microg/kg). The mean acrylamide exposure of the NFCS participants was 0.48 microg/kg bw/day. Risk of neurotoxicity is negligible. From exposure estimations it appears that the additional cancer risk might not be negligible.
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Affiliation(s)
- E J M Konings
- The Food and Consumer Product Safety Authority/Inspectorate for Health Protection and Veterinary Public Health, Region South, PO Box 2168, 5600 CD Eindhoven, The Netherlands.
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Hiemstra M, de Kok A. Determination of trinexapac in wheat by liquid chromatography-electrospray ionization tandem mass spectrometry. J Agric Food Chem 2003; 51:5855-5860. [PMID: 13129284 DOI: 10.1021/jf030302v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A quantitative and confirmatory method for the analysis of trinexapac (free acid metabolite of trinexapac-ethyl) in wheat is described. Residues were extracted from wheat with acetonitrile in aqueous phosphate buffer (pH 7) overnight. The extract was directly injected into the HPLC system. Chromatographic separation was achieved on an octadecylsilica column, and detection was performed by negative ion electrospray ionization tandem mass spectrometry. The precursor ion of trinexapac [M - H](-) at m/z 223 was subjected to collisional fragmentation with argon to yield two intense diagnostic product ions at m/z 135 and 179, respectively. Accuracy and specificity for routine analysis of trinexapac were demonstrated. The validated concentration range was 10-200 microg/kg based on a 0.10 g/mL wheat sample extract. Recoveries were within the range of 71-94%, with associated relative standard deviations better than 10%. The limit of detection for trinexapac in wheat was estimated at 5 microg/kg. The method has been applied to a survey of 100 samples of wheat. In 46% of the samples analyzed, a quantifiable amount of trinexapac was detected, ranging from 10 to 110 microg/kg. It has been demonstrated that analyses of trinexapac accurately reflect the total amount of residues of the plant growth regulator, trinexapac-ethyl, in the wheat samples following field application. No residues of the parent compound, trinexapac-ethyl, in wheat were detected.
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Affiliation(s)
- Maurice Hiemstra
- Pesticide Analysis Group, Research and Development Department, Inspectorate for Health Protection and Veterinary Public Health, Dutch Food and Non-Food Authority, Hoogte Kadijk 401, 1018 BK Amsterdam, The Netherlands.
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Hiemstra M, de Kok A. Determination of propamocarb in vegetables using polymer-based high-performance liquid chromatography coupled with electrospray mass spectrometry. J Chromatogr A 2002; 972:231-9. [PMID: 12416881 DOI: 10.1016/s0021-9673(02)01089-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A method for the determination of propamocarb in vegetables with liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS) was developed. The performance of a polymer-based analytical LC column for the separation was investigated. Residues of propamocarb were extracted from the matrix with methanol. Subsequently, the extract was directly injected into the LC-MS system, without any additional concentration or cleanup procedures. Separation of propamocarb from the matrix components was achieved on a polymethacrylate-based analytical column. Propamocarb was concurrently detected with electrospray ionisation mass spectrometry in the selected ion monitoring mode and two-stage full scan MS application. Quantitation was done with matrix-matched calibration standards of propamocarb. Unambiguous confirmation was achieved by comparison of the full scan product ion mass spectrum of the chromatographic peak in the sample with the spectrum of a standard solution of propamocarb at the same retention time. The analytical performance of the method was validated for five relevant matrices, spiking propamocarb at fortification levels from 0.05 to 15.0 mg kg(-1). This covers the range of maximum residue limits in agricultural commodities, stated in the Dutch national legislation. The mean recovery of propamocarb was better than 90% with a precision of less than 10% in both scanning applications. As could be concluded from the calibration curve and matrix background levels, observed in blank control samples, the estimated limit of detection was 25 microg kg(-1) for the two-stage full scan MS application. The method has been applied in a survey of 285 samples of lettuce, radish, leek, and cabbage for the presence of residues of propamocarb. In 50% of the samples analysed, a residue of propamocarb was detected.
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Affiliation(s)
- Maurice Hiemstra
- Inspectorate for Health Protection, Food Inspection Service, Research and Development Department, Amsterdam, The Netherlands.
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Hiemstra M, Schaefers-Okkens AC, Teske E, Kooistra HS. [The reliability of vaginal cytology in determining the optimal mating time in the bitch]. Tijdschr Diergeneeskd 2001; 126:685-9. [PMID: 11723807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The reliability of vaginal cytology for determining the optimal mating period is controversial. The importance of the site for obtaining the smear (the vestibule or the vagina) and the best staining method are also unclear. Therefore, we investigated the reliability of vaginal cytology as compared to plasma progesterone concentrations for determining the optimal mating period. Additionally, the influence of different locations for obtaining the smears and of the staining methods, i.e. May-Grünwald-Giemsa or Papanicolaou, a method that stains keratin in superficial cells, was examined. In total, the vaginal cytology of 35 bitches during the follicular phase was examined three times a week, until the optimal time for mating was established, based on plasma progesterone concentrations measured with a 125Iodine radio-immunoassay. The results indicate that vaginal cytology is not useful for determining the optimal mating period in bitches, since mating according to cytological findings would have resulted in only 28% of the bitches being mated at the proper time. The site for obtaining the smear and the staining method did not affect accuracy. It is therefore concluded that cytology is not useful in breeding management to determine the optimal mating period. It can be used, however, to determine the stage of the cycle in general, e.g. the early part of the follicular phase or the metoestrus and the detection of disorders in the follicular phase. For this purpose, a smear from the vestibule, stained with a morphological staining method, provides sufficient information.
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Affiliation(s)
- M Hiemstra
- Hoofdafdeling Geneeskunde van Gezelschapsdieren, Afdeling Voortplanting, Postbus 80154, 3508 TD Utrecht
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Hiemstra M, de Kok A. Determination of N-methylcarbamate pesticides in environmental water samples using automated on-line trace enrichment with exchangeable cartridges and high-performance liquid chromatography. J Chromatogr A 1994. [DOI: 10.1016/0021-9673(94)89063-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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De Kok A, Hiemstra M, Vreeker CP. Optimization of the postcolumn hydrolysis reaction on solid phases for the routine high-performance liquid chromatographic determination of N-methylcarbamate pesticides in food products. J Chromatogr A 1990; 507:459-72. [PMID: 2380308 DOI: 10.1016/s0021-9673(01)84225-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Various solid-phase materials were evaluated as catalysts for the postcolumn hydrolysis of N-methylcarbamate pesticides in a high-performance liquid chromatographic (HPLC) method for food products. Inexpensive magnesium oxide has been used for the first time in HPLC as a very efficient catalyst and as a good alternative for, e.g., expensive anion-exchange resins. The reaction mechanism and kinetics were studied through measurement of the reaction band broadening, which depends on the stationary phase, mobile phase composition and flow-rate, and reaction temperature. Also, relationships between carbamate structure and reactivity were examined. The usefulness of the optimized postcolumn system was thoroughly tested by application to crop sample analysis during an extended period of time. The range of application of the solid-phase reaction was extended to 22 carbamate pesticides and ten of their metabolites. For crop sample analysis, limits of determination in the range 1-10 ppb were obtained.
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Affiliation(s)
- A De Kok
- Governmental Food Inspection Service, Pesticide Analysis Department, Alkmaar, The Netherlands
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