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1.
Regul Toxicol Pharmacol ; 72(3): 562-8, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26003512

RESUMEN

Hair straightening cosmetic products may contain formaldehyde (FA). In Europe, FA is permitted for use in personal care products at concentrations ⩽ 0.2g/100g. According to the Cosmetic Ingredient Review (CIR) Expert Panel products are safe when formalin (a 37% saturated solution of FA in water) concentration does not exceed 0.2g/100g (0.074 g/100g calculated as FA). The official method of reference does not discriminate between "free" FA and FA released into the air after heating FA donors. The method presented here captures and collects the FA released into the air from heated cosmetic products by derivatization with 2,4-dinitrophenylhydrazine and final analysis by UPLC/DAD instrument. Reliable data in terms of linearity, recovery, repeatability and sensitivity are obtained. On a total of 72 market cosmetic products analyzed, 42% showed FA concentrations very close to or above the threshold value (0.074 g/100g calculated as FA) suggested by the Cosmetic Ingredient Review committee, whereas 11 products, negative using the official method of reference, were close to or above the threshold value (0.074 g/100g calculated as FA). This may pose a health problem for occasional users and professional hair stylists.


Asunto(s)
Contaminantes Atmosféricos/análisis , Cosméticos/análisis , Formaldehído/análisis , Seguridad Química , Seguridad de Productos para el Consumidor , Cabello , Calor , Humanos , Exposición por Inhalación/análisis , Medición de Riesgo
2.
J Chromatogr A ; 1218(9): 1253-9, 2011 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-21277578

RESUMEN

This study proposes a fast, simple and sensitive liquid chromatography diode array detector (LC/UV-DAD)-based method for the simultaneous determination of eight sulfonylurea herbicides (bensulfuron methyl, chlorsulfuron, metsulfuron methyl, primisulfuron methyl, rimsulfuron, thifensulfuron methyl, triasulfuron and tribenuron methyl) in bovine whole milk at concentrations lower than the default limit of 0.01 mg kg(-1) allowed by current legislation (Regulation EC/396/2005 and following Annexes). An effective one-step solid phase extraction (SPE) and clean up procedure was defined with use of Chem Elut cartridges, providing good recoveries for all the analytes tested and with no matrix effects affecting method accuracy. Separation of herbicides was obtained on a C(18) column by acetonitrile- water gradient elution. Method validation has been performed according to European Commission Decision 2002/657/EC criteria, in terms of linearity, recovery, precision, specificity, decision limit (CC(α)) and detection capability (CC(ß)). Typical recoveries ranged between 78.4% and 99.7%, at the maximum residue limits (MRLs) levels established by Regulation EC/396/2005, with relative standard deviations (RSD) no larger than 10%.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Residuos de Medicamentos/análisis , Herbicidas/análisis , Leche/química , Extracción en Fase Sólida/métodos , Compuestos de Sulfonilurea/análisis , Animales , Bovinos , Residuos de Medicamentos/aislamiento & purificación , Herbicidas/aislamiento & purificación , Análisis de los Mínimos Cuadrados , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría Ultravioleta , Compuestos de Sulfonilurea/aislamiento & purificación
3.
J Chromatogr A ; 1214(1-2): 115-20, 2008 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-19004450

RESUMEN

In this paper we have developed an analytical method for the simultaneous determination of four nicotinoid insecticides [acetamiprid (ACT), imidacloprid (ICL), thiacloprid (TCL) and thiamethoxam (TMX)] in bovine whole milk. These analytes were extracted, in a single step with dichloromethane, from fortified milk samples, using Chem Elut cartridges, containing diatomaceous earth material. Insecticide's determination and quantification were performed by HPLC with diode-array detection (DAD). Average recoveries of the four insecticides from bovine milk samples were between 85.1 and 99.7% at spiking levels 0.01, 0.05 and 0.1 mg kg(-1). Relative standard deviations (RSDs) were no larger than 10% for all of the recovery tests. The calculated limits of quantitation (LOQ) ranged from 0.01 to 0.04 mg kg(-1) for the four insecticides, being equal to or lower than the maximum residue limits (MRLs) established by European legislation (0.01-0.05 mg kg(-1)). The developed method is linear at concentrations within the tested interval, with coefficients of determination higher than 0.9990. According to Commission Decision 2002/657/EC, decision limit (CCalpha) and detection capability (CCbeta) have been calculated. The proposed method is rapid, simple and could be utilized for the routine analysis of pesticides residues.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Contaminación de Alimentos/análisis , Insecticidas/análisis , Leche/química , Residuos de Plaguicidas/análisis , Extracción en Fase Sólida , Animales , Bovinos , Imidazoles/análisis , Análisis de los Mínimos Cuadrados , Neonicotinoides , Nitrocompuestos/análisis , Oxazinas/análisis , Piridinas/análisis , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Tiametoxam , Tiazinas/análisis , Tiazoles/análisis
4.
J Chromatogr A ; 1108(1): 1-6, 2006 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-16448655

RESUMEN

A rapid and simple method for simultaneous analysis of four neonicotinoid insecticides including acetamiprid, imidacloprid, thiacloprid and thiamethoxam in fruit and vegetable matrices has been developed. For instance, ready-to-use cartridges filled with a macroporous diatomaceous material were used to extract in a single step insecticide residues with dichloromethane from aqueous-acetone extracts of fruits and vegetables. The eluate was evaporated, the residue redissolved with methanol and then analyzed by liquid chromatography-mass spectrometry in the electrospray ionization (ESI) positive mode. Average recoveries of the four pesticides were between 74.5 and 105% at both spiking levels 0.1 and 1.0 mg kg(-1) in peach, pear, courgette, celery and apricot. Relative standard deviations (RSDs) were less than 10% for all of the recovery tests. The calculated limits of quantitation (LOQs) (0.1-0.5 mg kg(-1)) were equal or lower then the maximum residue limits (MRLs) established by European legislation (0.1-0.5 mg kg(-1)). The proposed method is fast, easy to perform and could be utilized for monitoring of pesticides residues.


Asunto(s)
Fraccionamiento Químico/métodos , Frutas/química , Insecticidas/análisis , Residuos de Plaguicidas/análisis , Verduras/química , Cromatografía Liquida/métodos , Imidazoles/análisis , Neonicotinoides , Nitrocompuestos/análisis , Oxazinas/análisis , Piridinas/análisis , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray/métodos , Tiametoxam , Tiazinas/análisis , Tiazoles
5.
J Chromatogr A ; 1094(1-2): 175-8, 2005 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-16257305

RESUMEN

An analytical method for the routine simultaneous determination of four nicotinoid insecticides (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) in commercial multifloral honey was developed. Fortified honey samples, dissolved in water, were cleaned up through Extrelut NT20 column and, finally, insecticides were eluted with dichloromethane. The eluate was evaporated, the residue redissolved in methanol and then analyzed by LC-ESI(+)-MS. Average recoveries of the four analytes were in the range of 76% and 99% at both spiking levels 0.1 and 1.0 mg kg(-1). Relative standard deviations (RSDs) were less than 10% for all of the recovery tests. The detection limits (LODs) of the method ranged from 0.01 to 0.1 mg kg(-1) for the different insecticides studied. The developed method is linear over the range assayed, 0.5-5.0 microg mL(-1), with linear correlation coefficients higher than 0.9993.


Asunto(s)
Miel/análisis , Nicotina/análisis , Residuos de Plaguicidas/análisis , Espectrometría de Masa por Ionización de Electrospray/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
6.
Biomed Chromatogr ; 19(10): 766-70, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15915539

RESUMEN

We describe a method for determination of cymoxanil, 1-2-cyano-2-methoxy(iminoacetyl)-3-ethylurea, in drinking water and in soil, using reversed-phase HPLC with UV detection at 240 nm and a mobile phase of acetonitrile-water (30:70, v/v). Fortified water samples (1.0 L) were extracted with solid-phase extraction on Strata X. Soil samples (20 g) were extracted with acetone and the extracts were transferred onto Strata C18E. The recoveries of cymoxanil from water and soil samples were over 85% for each fortification level. The RDS were within the range 1.7-4.1% for water and 0.9-1.2% for soil samples. After optimization of the extraction and separation conditions, the method was validated.


Asunto(s)
Acetamidas/análisis , Cromatografía Líquida de Alta Presión/métodos , Contaminantes del Suelo/análisis , Contaminantes Químicos del Agua/análisis , Fraccionamiento Químico/métodos , Reproducibilidad de los Resultados , Abastecimiento de Agua/análisis
7.
Biomed Chromatogr ; 19(7): 506-12, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15651091

RESUMEN

The photochemical degradation of the fungicide cymoxanil {2-cyano-N-[(ethylamino)carbonyl]-2-(methoxyimino) acetamide} was studied in aqueous buffer solution (pH 5.9+/- 0.1) under UV light and in laboratory conditions. The degradation followed a pseudo- first-order kinetic with significant correlation coefficient. The main photoproducts were separated and tentatively identified by HPLC/UV and HPLC/MS data, as 3-ethyl-4-(methoxyamino)-2,5-dioxo-4-imidazolidinecarbonitrile, 1-ethyl-5-(methoxyimino)-2,4-imidazolidin-2,4-dione, ethylimidazolidinetrione and {[(ethylamino)carbonyl]-amino}oxoacetic acid. A photolysis pathway of cymoxanil is proposed.


Asunto(s)
Acetamidas/química , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas/métodos , Acetamidas/aislamiento & purificación , Acetamidas/efectos de la radiación , Fungicidas Industriales/química , Fungicidas Industriales/efectos de la radiación , Cinética , Fotólisis , Sensibilidad y Especificidad , Espectrofotometría Ultravioleta
8.
Biomed Chromatogr ; 19(1): 107-10, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15470700

RESUMEN

A multi-residue method for the simultaneous extraction from drinking water using solid-phase extraction on LiChrolut EN [poly(styrene-divinylbenzene), PSDVB] and determination of nine N-methylcarbamate pesticides (NMCs) (aldicarb, its metabolites i.e. aldicarb sulfone and aldicarb sulfoxide and carbaryl, carbofuran, dioxacarb, ethiofencarb, methomyl and propoxur) using reversed-phase liquid chromatography was studied. A 1000-fold pre-concentration was achieved and the method was used for determination of the nine pesticides in water, with limits of detection in the range 3-15 ng L(-1). For all compounds the recoveries determined at the 0.1 and 1 microg L(-1) level generally ranged from 85 to 104% with relative standard deviations (RSD) of 1.4-8.8%.


Asunto(s)
Carbamatos/análisis , Cromatografía Líquida de Alta Presión/métodos , Plaguicidas/análisis , Abastecimiento de Agua/análisis , Carbamatos/aislamiento & purificación , Poliestirenos
9.
Biomed Chromatogr ; 18(7): 450-6, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15340970

RESUMEN

Photolysis of imazosulfuron was studied in aqueous solution under UV light. The reaction followed a pseudo-first-order kinetic with significant correlation coefficient. The major photodegradation products of imazosulfuron after irradiation under UV light were separated and tentatively identified by HPLC-MS analysis as (4,6-dimethoxypyrimidine-2-yl)aminocarbonylsulfamic acid, 4,6-dimethoxy-2-ureidopyrimidine and 2,2'-dichloro-[3,3'] bi [imidazo[1,2-a] pyridinyl]. The results indicate that different reaction pathways are followed: (1) cleavage of the sulfonylurea bridge; (2) desulfonylation, which can proceed either by a carbon-sulfur cleavage or a nitrogen-sulfur cleavage. A mechanism for the formation of the photoproducts is proposed.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Piridinas/química , Pirimidinas/química , Cinética , Fotoquímica , Espectrofotometría Ultravioleta
10.
J Agric Food Chem ; 52(1): 99-104, 2004 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-14709020

RESUMEN

The kinetics and mechanism(s) of the hydrolytic degradation of a compound are needed to evaluate a compound's abiotic degradation in the environment. In this paper, the hydrolysis of cymoxanil [2-cyano-N-[(ethylamino)carbonyl]-2-(methoxyimino) acetamide] was investigated in dark sterile aqueous solutions under a variety of pH conditions (pH 2.8-9.2) and temperatures (15-50 degrees C). Hydrolysis of cymoxanil was described by first-order kinetics, which was dependent on pH and temperature. Cymoxanil degraded rapidly at pH 9 (half-life = 31 min) and relatively slowly at pH 2.8 (half-life = 722 days). The effect of temperature on the rate of cymoxanil degradation was characterized using the Arrhenius equation with an estimated energy of activation of 117.1 kJ mol(-)(1). An increase in temperature of 10 degrees C resulted in a decrease in half-life by a factor of approximately 5. Three competing degradation pathways are proposed for the hydrolysis of cymoxanil, with two of the pathways accounting for approximately 90% of cymoxanil degradation. These two pathways involved either initial cyclization to 1-ethyldihydro-6-imino-2,3,5(3H)-pyrimidinetrione-5-(O-methyloxime) (1, Figure 1) or direct cleavage of the C-1 amide bond to form cyano(methoxyimino) acetic acid (7). The third pathway of degradation involved initial cyclization to 3-ethyl-4-(methoxyimino)-2,5-dioxo-4-imidazolidinecarbonitrile (8), which rapidly degrades into 1-ethyl-5-(methoxyimino)-2,4-imidazoline-2,4-dione (9). All three pathways eventually lead to the formation of the polar metabolite oxalic acid.


Asunto(s)
Acetamidas/química , Fungicidas Industriales/química , Tampones (Química) , Fenómenos Químicos , Química Física , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Ácido Oxálico/química , Soluciones , Temperatura , Termodinámica
11.
Biomed Chromatogr ; 16(8): 489-94, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12474209

RESUMEN

Imazosulfuron, 1-(2-chloroimidazo [1,2-a] pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl)urea, is a new sulfonylurea herbicide applied once per growing season. It is highly active at low application levels and is used to control most annual and perennial broad-leaf weeds and some grasses in cereal crop. In this work the degradation of imazosulfuron in four different soils was investigated under aerobic laboratory conditions to evaluate its environmental fate. Test soils were treated with this herbicide in acetonitrile to obtain a final concentration of 0.2 mg kg(-1) (100 g ha(-1)), extracted with methylene chloride and analyzed by reversed-phase liquid chromatography (RP-HPLC) using a C(18) column coupled with UV detection. Recoveries of spiked soils ranged from 84.3 to 99.8% (RDS 0.0-4.9%; n = 4). The limits of quantitation ranged from 0.002 to 0.004 mg kg(-1). Imazosulfuron half-life, t(1/2), was calculated in each of the investigated soil. In aerobic conditions it ranged between 1 and 50 days.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Herbicidas/química , Piridinas/análisis , Pirimidinas/análisis , Contaminantes del Suelo/análisis , Compuestos de Sulfonilurea , Piridinas/química , Pirimidinas/química , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría Ultravioleta
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