Detection and quantification of adulterations in aged wine using RGB digital images combined with multivariate chemometric techniques.

A method has been developed to authenticate aged high-quality wines and to quantify their potential adulterations through multivariate analysis and regression techniques applied to the obtained RGB digital images. Wines of pure Gran Reserva, Crianza, and Joven Rioja as well as synthetic adulterated Gran Reserva samples were studied. Digital images were obtained by a single and inexpensive lab-made device. Each sample was characterized by means of the 256 channels intensities from the RGB-colorgram. Multivariate image analysis revealed differences among the wine classes, and between genuine-aged and adulterated samples. Partial least squares regression was used to develop a model for estimating the adulteration degree of Gran Reserva wines. The model achieved good prediction (RMSEP = 1.6), appropriate precision (RSD = 2.5%) and suitable LOD (2.3%) to quantify cost-effective adulterations. The present method, due to simplicity and low cost, could provide an appropriate alternative to the traditional chemical authentication methods.

Psychometrics of the SCL-90-R and Development and Testing of Brief Versions SCL-45 and SCL-9 in Infertile Couples.

BACKGROUND: Although infertile couples are mentally healthy, dealing with infertility and assisted reproductive technology (ART) treatment is usually associated with psychological distress. It would therefore be useful to have short, multidimensional instruments to be able to identify people who present more intense emotional reactions and follow up their emotional distress throughout the ART. OBJECTIVES: The goals of the study were to analyze the psychometric adequacy of the original 90-item version of the Symptom Checklist (SCL-90) in a sample of Spanish women and their partners undergoing ART, as well as to develop and analyze two brief versions of the SCL-90, given the absence of adequate short versions for this population. METHODS: A cross-sectional design for patients and their partners in the process of ART through in vitro fertilization was used. The two brief scales were obtained, which took into account the levels of variance explained by the items and confirmatory factor analysis. RESULTS: Two brief instruments were developed. The first, with 45 items (SCL-45-I Infertility), includes nine subdimensions: Somatization, Interpersonal Sensitivity, Obsessive-Compulsive Disorder, Depression, Anxiety, Hostility, Paranoid Ideation, Phobic Anxiety, and Psychoticism. The second instrument contains nine items (SCL-9-I or Global Severity Index [GSI]), one item for each dimension. Both instruments were psychometrically adequate (SCL-45-I: χ/df = 7.24, RMSEA = .057, 95% CI [.056, .059], CFI = .97, NNFI = .97, SRMR = .049; SCL-9-I: χ/df = 9.66, RMSEA = .068, 95% CI [.061, .076], CFI = .97, NNFI = .96, SRMR = .035). Measurement invariance analysis by gender was conducted, and the instruments were shown to be suitable for both men and women. DISCUSSION: The suitability of the SCL-90-R for use in ART was verified, and two valid instruments-useful and easy to use for nurses, psychologists, and other care providers-were developed.

Marital functioning and treatment outcome in couples undergoing assisted reproduction.

AIM: To investigate the relationship between the quality of marital functioning and communication, individual psychological symptomatology, and pregnancy achievement in couples undergoing assisted reproduction. BACKGROUND: The results concerning marital functioning and the feasibility of pregnancy yield contradictory outcomes and the quality of the relationship of the couple undergoing assisted reproduction has not been analysed from systemic models. Our hypothesis is that when undergoing assisted reproduction treatment (ART), the couple's functioning and communication will be related to the pregnancy rate. DESIGN: This study employs a cross-sectional design with couples receiving ART. METHODS: Spanish heterosexual couples (N = 185) completed the self-report instruments. The data were collected from 2010 - 2015. All the couples completed at least one treatment process, or at least 1 year had gone by since beginning the treatment. RESULTS: The association between couple relationship quality and the individual psychological symptomatology experienced during the assisted reproduction process was confirmed in men and women. Although both members of the couple experienced an increase of symptomatology, only men's symptomatology was statistically significantly linked to pregnancy achievement. CONCLUSION: It is necessary to support the couple from the assisted reproduction centres, promoting cohesion, flexibility, and communication in the relationship. The intervention process should also be understood from a systemic perspective; that is, considering dyadic transactions as a systemic unit. Two aspects seem to be especially relevant for clinical nurses in ART: (a) the man's role is crucial for treatment success; (b) the woman's communication is crucial to the process.

Use of Primary Care Services, Care Specialized and Drug Use by Population 65 Years and More in the Community of Madrid, Spain. / Utilización de servicios de atención primaria, atención especializada y consumo de medicamentos por la población de 65 años y más en la Comunidad de Madrid.

BACKGROUND: Ageing of the Spanish population results in an increase in health services required. Therefore, determine the frequency of the health services utilization in this age group and analyze their determinants has a great interest.The aim was to analyze the utilization of health services among older people living in two urban neighborhoods of northern Madrid. METHODS: A cross-sectional population-based study. It is studied a cohort of 1327 individuals ≥ 65 years, stratified by age and sex. Nine utilization indicators were defined. For each indicator frequencies and the association of each with the other variables were calculated by multivariate analysis. RESULTS: The distribution of indicators expressed as a percentage of the user population is: GP appoiments/month 64.8% (95%CI 62.3 to 67.4); nursing appoiments/month 44.6% (95% CI 41.2 to 47.2); home medical visits/month 3.1% (95%CI 2.2 to 4.1); home nursing visits/month 3% (95%CI 2.1 to 3.9); hospitalization/year 16.4% (95%CI 14.4 to 18.4); appoiments rheumatologist/orthopedic/year 25.1% (95%CI 22.7 to 27.4); physiotherapist appoiments/year 12.9% (95% CI 11.1 to 14.7); podiatrist appoiments/year 30.6% (95%CI 28.1 to 33.1) and polypharmacy (≥5 drugs) 55.7% (95% CI 53 to 58.4). Comorbidity was the best predictor of health care utilization ranging from OR 4.10 (95%CI: 3.07-5,49) to OR 1.39 (95%CI: 0.97-1.99) in polymedicated and visit the physiotherapist respectively. Cardiovascular disease (OR 1.34; 95%CI 1.03-1,76) and diabetes (OR 1.46; 95%CI: 1.05 -2.02) were independently associated with increased use of family doctor. Dependence was the main determinant for home healthcare (OR 3.38; 95%CI: 1.38-8.28) and nurses (OR 9.71; 95%CI: 4.19-22.48) Mood disorders were associated to polypharmacy (OR 2.06; 95%CI: 1,48-2.86) and to visits to family doctor (OR 1.52; 95%CI: 1,13-2.04). CONCLUSIONS: The comorbidity is the strongest predictor of health services utilization. Cardiovascular diseases and diabetes are independently associated to greater use. Dependence is the main determinant of home care. Mood disorders associated with polypharmacy and increased attendances to the General Practitioner.

OBJETIVO: El envejecimiento de la población española se traduce en un aumento de las prestaciones sanitarias requeridas por la población mayor, por ello conocer la frecuencia de la utilización de los servicios sanitarios de este grupo de edad y analizar sus factores determinantes es de especial interés. El objetivo fue analizar la utilización de servicios sanitarios de la población mayor residente en dos barrios urbanos del norte de Madrid. METODOS: Estudio transversal de base poblacional. Se estudió una cohorte de 1.327 individuos igual o mayor a 65 años, estratificada por edad y sexo. Se definieron 9 indicadores de utilización durante el mes anterio o durante el último año. Para cada indicador se calcularon las frecuencias y la asociación con el resto de variables mediante análisis multivariante. RESULTADOS: la distribución de los indicadores expresada como proporción de la población usuaria fue: consultas médico/mes 64,8% (IC95%:62,3-67,4); consultas enfermería/mes 44,6% (IC95%:41,2-47,2); domicilios médico/mes 3,1% (IC95%:2,2-4,1); domicilios enfermería/mes 3%(IC95%:2,1-3,9); hospitalización/año 16,4% (IC95%:14,4-18,4); consultas reumatólogo/traumatólogo/año 25,1% (IC95%:22,7-27,4); consultas fisioterapeuta/año 12,9% (IC95%:11,1-14,7); consultas podólogo/año 30,6% (IC95%:28,1-33,1) y polimedicados (≥5 fármacos) 55,7% (IC95%: 53-58,4). La comorbilidad fue la variable que mejor predijo la utilización de servicios sanitarios oscilando entre OR 4.10 (IC95%:3.07-5,49) y OR 1,39 (IC95%: 0.97-1.99) para estar polimedicado y visitar al fisioterapeuta respectivamente. Enfermedades cardiovasculares (OR 1,34; IC95%:1.03-1,76) y diabetes (OR 1,46; IC95%:1,05-2,02) se asociaron de forma independiente a mayor utilización del médico de familia. La dependencia fue el principal determinante de atención domiciliaria para el médico (OR 3,38; IC95%: 1,38-8,28) y para enfermería (OR 9.71; IC 95%: 4.19-22.48). Trastornos del ánimo se asociaron a mayor polimedicación (OR 2.06; IC95%: 1,48-2.86) y visitas al médico de familia (OR 1,52; IC 95%:1,13-2.04). CONCLUSIONES: La comorbilidad fue la variable que mejor predijo la utilización de servicios sanitarios. Las enfermedades cardiovasculares y la diabetes se asocian de forma independiente a mayor utilización de servicios. Los trastornos del ánimo se asocian a mayor polimedicación y más visitas al médico de familia.

Ultrasound-assisted magnetic solid-phase extraction for the determination of some transition metals in Orujo spirit samples by capillary electrophoresis.

Ultrasound-assisted magnetic solid-phase extraction coupled to capillary electrophoresis was optimized for the preconcentration and determination of Zn(II), Cu(II), Mn(II) and Cd(II) as their complexes with 1,10-phenanthroline (Phen). Both pre- and on-capillary complexations were employed to obtain stable metal-Phen complexes. The parameters that have an influence on the electrophoretic separation and the MSPE process were studied and optimized using different experimental designs. Metals were extracted from 10 mL of sample at pH 5 using 3mg of magnetic particles functionalized with carboxylic groups. The metals were eluted as metal-Phen complexes and analyzed by capillary electrophoresis. The method showed low limits of detection for metals 0.49-2.19 µg L(-1), and high preconcentration factors, 39-44, The efficiencies of the extraction method were in the range 77.1-87.5% and the precision (RSD < 10%) and accuracy were between 98.2% and 101.6%. The method was applied to the determination of the aforementioned metals in Galician Orujo spirit samples.

Utilización de servicios de atención primaria, atención especializada y consumo de medicamentos por la población de 65 años y más en la Comunidad de Madrid / Use of primary care services, care specialized and drug use by population 65 years and more in Madrid, Spain

Fundamento: El envejecimiento de la población española se traduce en un aumento de las prestaciones sanitarias requeridas por la población mayor, por ello conocer la frecuencia de la utilización de los servicios sanitarios de este grupo de edad y analizar sus factores determinantes es de especial interés. El objetivo fue analizar la utilización de servicios sanitarios de la población mayor residente en dos barrios urbanos del norte de Madrid. Métodos: Estudio transversal de base poblacional. Se estudió una cohorte de 1.327 individuos igual o mayor a 65 años, estratificada por edad y sexo. Se definieron 9 indicadores de utilización durante el mes anterio o durante el último año. Para cada indicador se calcularon las frecuencias y la asociación con el resto de variables mediante análisis multivariante. Resultados: la distribución de los indicadores expresada como proporción de la población usuaria fue: consultas médico/mes 64,8% (IC95%:62,3-67,4); consultas enfermería/mes 44,6% (IC95%:41,2-47,2); domicilios médico/mes 3,1% (IC95%:2,2-4,1); domicilios enfermería/mes 3%(IC95%:2,1-3,9); hospitalización/año 16,4% (IC95%:14,4-18,4); consultas reumatólogo/traumatólogo/año 25,1% (IC95%:22,7-27,4); consultas fisioterapeuta/año 12,9% (IC95%:11,1-14,7); consultas podólogo/año 30,6% (IC95%:28,1-33,1) y polimedicados (≥5 fármacos) 55,7% (IC95%: 53-58,4). La comorbilidad fue la variable que mejor predijo la utilización de servicios sanitarios oscilando entre OR 4.10 (IC95%:3.07-5,49) y OR 1,39 (IC95%: 0.97-1.99) para estar polimedicado y visitar al fisioterapeuta respectivamente. Enfermedades cardiovasculares (OR 1,34; IC95%:1.03-1,76) y diabetes (OR 1,46; IC95%:1,05-2,02) se asociaron de forma independiente a mayor utilización del médico de familia. La dependencia fue el principal determinante de atención domiciliaria para el médico (OR 3,38; IC95%: 1,38-8,28) y para enfermería (OR 9.71; IC 95%: 4.19-22.48). Trastornos del ánimo se asociaron a mayor polimedicación (OR 2.06; IC95%: 1,48-2.86) y visitas al médico de familia (OR 1,52; IC 95%:1,13-2.04). Conclusiones: La comorbilidad fue la variable que mejor predijo la utilización de servicios sanitarios. Las enfermedades cardiovasculares y la diabetes se asocian de forma independiente a mayor utilización de servicios. Los trastornos del ánimo se asocian a mayor polimedicación y más visitas al médico de familia (AU)

Background: Ageing of the Spanish population results in an increase in health services required. Therefore, determine the frequency of the health services utilization in this age group and analyze their determinants has a great interest.The aim was to analyze the utilization of health services among older people living in two urban neighborhoods of northern Madrid. Method: cross-sectional population-based study. It is studied a cohort of 1327 individuals ≥ 65 years, stratified by age and sex. Nine utilization indicators were defined. For each indicator frequencies and the association of each with the other variables were calculated by multivariate analysis. Results: The distribution of indicators expressed as a percentage of the user population is: GP appoiments/month 64.8% (95%CI 62.3 to 67.4); nursing appoiments/month 44.6% (95% CI 41.2 to 47.2); home medical visits/month 3.1% (95%CI 2.2 to 4.1); home nursing visits/month 3% (95%CI 2.1 to 3.9); hospitalization/year 16.4% (95%CI 14.4 to 18.4); appoiments rheumatologist/orthopedic/year 25.1% (95%CI 22.7 to 27.4); physiotherapist appoiments/year 12.9% (95% CI 11.1 to 14.7); podiatrist appoiments/year 30.6% (95%CI 28.1 to 33.1) and polypharmacy (≥5 drugs) 55.7% (95% CI 53 to 58.4). Comorbidity was the best predictor of health care utilization ranging from OR 4.10 (95%CI: 3.07-5,49) to OR 1.39 (95%CI: 0.97-1.99) in polymedicated and visit the physiotherapist respectively. Cardiovascular disease (OR 1.34; 95%CI 1.03-1,76) and diabetes (OR 1.46; 95%CI: 1.05 -2.02) were independently associated with increased use of family doctor. Dependence was the main determinant for home healthcare (OR 3.38; 95%CI: 1.38-8.28) and nurses (OR 9.71; 95%CI: 4.19-22.48) Mood disorders were associated to polypharmacy (OR 2.06; 95%CI: 1,48-2.86) and to visits to family doctor (OR 1.52; 95%CI: 1,13-2.04). Conclusions: The comorbidity is the strongest predictor of health services utilization. Cardiovascular diseases and diabetes are independently associated to greater use. Dependence is the main determinant of home care. Mood disorders associated with polypharmacy and increased attendances to the General Practitioner (AU)

Chemometric classification of potatoes with protected designation of origin according to their producing area and variety.

Potatoes from Galicia (northwestern Spain) are subjected to a Protected Geographic Indication (PGI) according to European legislation. Ten trace elements (Li, Na, K, Rb, Ca, Fe, Mg, Mn, Cu, and Zn) have been determined by atomic spectrometry in two sets of potato samples: Geo-Origin.set and Variety.set. The first data set is composed of samples of the only variety authorized by PGI (Kennebec) with two geographical origins: Galician and non-Galician. The second set corresponds to samples from different varieties but with only Galician geographical origin. Chemometric pattern recognition techniques have been applied to the study of potato geographical and varietal origins in relation to their capability for translocating metals from soil to tuber. Also, authentication models for classifying potato samples with Galician PGI based on metal fingerprints have been developed. The results obtained showed that samples of the same variety, Kennebec, have different metal fingerprints when they have been produced in different geographic locations. Also, diverse potato varieties cultivated on equal geographic Galician origin presented different metal profiles as well. Therefore, it can be concluded that classification studies on the differentiation of geographical origin of foods should take into account information of production area together with varietal data. Otherwise, classification obtained on the basis of the geographical origin could be due to the different variety or vice versa. Finally, two models were constructed for Kennebec Galician samples against Kennebec from other origins as well as against other varieties cultivated in Galicia (Liseta and Baraka). Both models achieved adequate classification rates (93-100%), good sensitivities, and total specificities (100%), allowing the fraud detection in the PGI label.

Frailty prevalence and slow walking speed in persons age 65 and older: implications for primary care.

BACKGROUND: Frailty in the elderly increases their vulnerability and leads to a greater risk of adverse events. According to various studies, the prevalence of the frailty syndrome in persons age 65 and over ranges between 3% and 37%, depending on age and sex. Walking speed in itself is considered a simple indicator of health status and of survival in older persons. Detecting frailty in primary care consultations can help improve care of the elderly, and walking speed may be an indicator that could facilitate the early diagnosis of frailty in primary care. The objective of this work was to estimate frailty-syndrome prevalence and walking speed in an urban population aged 65 years and over, and to analyze the relationship between the two indicators from the perspective of early diagnosis of frailty in the primary care setting. METHODS: Population cohort of persons age 65 and over from two urban neighborhoods in northern Madrid (Spain). Cross-sectional analysis. Bivariate and multivariate analysis with binary logistic regression to study the variables associated with frailty. Different cut-off points between 0.4 and 1.4 m/s were used to study walking speed in this population. The relationship between frailty and walking speed was analyzed using likelihood ratios. RESULTS: The study sample comprised 1,327 individuals age 65 and older with mean age 75.41 ± 7.41 years; 53.4% were women. Estimated frailty in the study population was 10.5% [95% CI: 8.9-12.3]. Frailty increased with age (OR = 1.14; 95% CI: 1.10-1.19) and was associated with poor self-rated health (OR = 2.52; 95% CI: 1.43-4.44), number of drugs prescribed (OR = 1.17; 95% CI: 1.08-1.26) and disability (OR = 6.58; 95% CI: 3.92-11.05). Walking speed less than 0.8 m/s was found in 42.6% of cases and in 56.4% of persons age 75 and over. Walking speed greater than 0.9 m/s ruled out frailty in the study sample. Persons age 75 and older with walking speed <0.8 m/s are at particularly high risk of frailty (32.1%). CONCLUSIONS: Frailty-syndrome prevalence is high in persons aged 75 and over. Detection of walking speed <0.8 m/s is a simple approach to the diagnosis of frailty in the primary care setting.

A new flow injection preconcentration method based on multiwalled carbon nanotubes for the ETA-AAS determination of Cd in urine.

A new flow injection (FIA) procedure for the preconcentration of cadmium in urine using multiwalled carbon nanotubes (MWCNT) as sorbent and posterior electrothermal atomization atomic absorption spectrometry (ETA-AAS) Cd determination has been developed. Cadmium was retained in a column filled with previously oxidized MWCNTs and it was quantitatively eluted with a nitric acid solution. The parameters influencing the adsorption-elution process such as pH of the sample solution, amount of sorbent and flow rates of sample as well as eluent solutions have been studied. Cd concentration in the eluent was measured by ETA-AAS under the optimized conditions obtained. The results indicated the elimination of urine matrix effect as a consequence of the preconcentration process performed. Total recovery of cadmium from urine at pH 7.2 using a column with 45 mg of MWCNTs as sorbent and employing a HNO(3) 0.5 mol L(-1) solution for elution was attained. The detection limit obtained was 0.010 µg L(-1) and the preconcentration factor achieved was 3.4. The method showed adequate precision (RSD: 3.4-9.8%) and accuracy (mean recovery: 97.4-100%). The developed method was applied for the determination of cadmium in real urine samples from healthy people (in the range of 0.14-2.94 µg L(-1)) with satisfactory results.

Comparison of several chemometric techniques for the classification of orujo distillate alcoholic samples from Galicia (northwest Spain) according to their certified brand of origin.

This paper has a double objective. The first goal was to develop an authentication system to differentiate between traditional orujo alcoholic distillates with and without a certified brand of origin (CBO). Owing to their low price and quality, samples without a CBO can be used as substrates for falsification of genuine CBO ones. The second objective was to perform a comparison of the abilities of the different chemometric procedures employed for this classification. The classification was performed on the basis of the chemical information contained in the metal composition of the orujo distillates. Eight metals determined by electrothermal atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry were considered (Ca, Cd, Cr, Cu, K, Mg, Na and Ni). After the appropriate pretreatment, the data were processed using different chemometric techniques. In the first stage, principal component analysis and cluster analysis were employed to reveal the latent structure contained in the data. Once it had been demonstrated that a relation exists between the metal composition and the raw materials, and not between the metal composition and the distillation systems employed for the orujo production, the second step consisted in the comparative application of different supervised pattern recognition procedures (such as linear discriminant analysis, K-nearest neighbours, soft independent modelling of class analogy, UNEQ and different artificial neural network approaches, including multilayer feed-forward, support vector machines, learning vector quantization and probabilistic neural networks). The results showed the different capabilities of the diverse classification techniques to discriminate between Galician orujo samples. The best results were those provided by probabilistic neural networks, in which the correct recognition abilities for CBO classes and without CBO classes were 98.6 +/- 3.1 and 98.0 +/- 4.5%; the prediction results were 87.7 +/- 3.3 and 86.2 +/- 5.0%, respectively. The usefulness of chemical metal analysis in combination with chemometric techniques to develop a classification procedure to authenticate Galician CBO orujo samples is demonstrated.

Headspace solid-phase microextraction gas chromatography-mass spectrometry analysis of volatiles in orujo spirits from a defined geographical origin.

A headspace solid-phase microextraction (HS-SPME) and gas chromatography-selective ion monitoring/mass spectrometry (GC-SIM/MS) method was optimized for analysis of 22 volatile compounds in orujo spirit samples from the Geographic Denomination "Orujo de Galicia/Augardente de Galicia". HS-SPME experimental conditions, such as fiber coating, extraction temperature, extraction and pre-equilibrium time, sample volume, and the presence of salt, were studied to improve the extraction process. The best results were obtained using a 65 microm Carbowax-divinylbenzene fiber during a headspace extraction at 40 degrees C with constant magnetic stirring for 15 min and after a 5 min period of pre-equilibrium time. The sample volume was 6 mL of orujo containing 25% of NaCl, placed in 12 mL glass vials equipped with a screw cap and PTFE/silicone septum. Desorption was performed directly in the gas chromatograph injector port for 5 min at 250 degrees C using the splitless mode. The proposed method is sensible (with detection limits between 0.0045 and 0.2399 mg/L), precise (with coefficients of variation in the range 0.99-8.18%), and linear over more than 1 order of magnitude. The developed method presented recoveries comprised between 76.0 and 112.4%. The applicability of the new method was demonstrated by determining the considered 22 volatile compounds in nine orujo commercial samples with quality and origin brands.

Preliminary chemometric study on the use of honey as an environmental marker in Galicia (northwestern Spain).

Thirteen metal elements were determined in 40 honey samples from Galicia with different environmental origins: rural, urban, and industrial areas. The data set of the honey metallic profiles was studied with a double purpose: first, to make a preliminary evaluation of honey as an environmental indicator in Galicia with the aim of monitoring pollution and, second, to compare the different capabilities of diverse pattern recognition prediction procedures for modeling the environmental surrounding of the hive. A certain level of similarity for urban and industrial samples was obtained using principal component analysis and cluster analysis, whereas significant differences for urban and industrial honeys were found in relation to rural honey samples. Different classification rules to associate metal content of honeys with their environmental surrounding were obtained by chemometric pattern recognition procedures. In general, the classification methods developed by neural networks provided better results than the traditional pattern recognition procedures. The metal profiles of honey seem to provide sufficient information to enable categorization criteria for classifying samples according to their environmental surrounding. Thus, honey could be a potential pollution indicator for the Galician area.

Erythrocyte rouleau formation under polarized electromagnetic fields.

We study the influence of an external electromagnetic field of 1.8 GHz in the formation or disaggregation of long rouleau of identical erythrocyte cells. In particular we calculate the variation of the transmembrane potential of an individual erythrocyte illuminated by the external field due to the presence of the neighboring erythrocytes in the rouleau, and compare the total electric energy of isolated cells with the total electric energy of the rouleau. We show that the polarization of the external electromagnetic field plays a fundamental role in the total energy variation of the cell system, and consequently in the formation or disaggregation of rouleau.

Comparison of ultrasound-assisted extraction and direct immersion solid-phase microextraction methods for the analysis of monoterpenoids in wine.

Ultrasound-assisted extraction (UAE) and direct immersion solid-phase microextraction (DI-SPME) were evaluated for the monoterpenic compounds determination in wine samples. The wine extracts obtained were analyzed by gas chromatography-mass spectrometry (GC-MS). The optimization of the variables affecting UAE and SPME methods was carried out in order to achieve the best extraction efficiency. Both UAE and SPME are quantitative (recoveries in the range 93-97% and 71.8-90.9%, respectively), precise (coefficients of variation below 5.5%), sensitive (limits of detection between 30-39mugL(-1) and 11-25mugL(-1), respectively) and linear over one order of magnitude. The application of both methods to red wine samples showed that UAE provided higher extraction of monoterpenic compounds than SPME. Although SPME remains an attractive alternative technique due to its speed, low sample volume requirements and solvent free character.

Solid-phase microextraction gas chromatography-mass spectrometry determination of monoterpenes in honey.

Solid-phase microextraction (SPME) using a 100 microm poly(dimethylsiloxane) (PDMS) fiber, followed by gas chromatography (GC-MS) determination, has been applied to the analysis of some monoterpenoids in honey. The extraction was performed by direct immersion of the fiber using a sampling period of 15 min with constant magnetic stirring (1100 rpm) and an extraction temperature of 20 degrees C. A 7 mL sample volume of an aqueous solution of honey with 25% of NaCl was placed in 15 mL glass vial fitted with screw cap and PTFE/silicone septum. Desorption was performed directly in the gas chromatograph injector port during 5 min at 250 degrees C using the splitless mode. The method is sensitive with detection limits between 11 and 25 microg L(-1), precise with coefficients of variation in the range 1.28 and 3.71%, and linear over more than one order of magnitude. The related conditions were used for honey sample analyses with recoveries between 71.8 and 90.9%. SPME remains an attractive alternative technique due to its rapidity and because it is a solvent free extraction method.

On void time determination in thermal field-flow fractionation.

Because of the temperature dependence of the carrier liquid density, the mass of carrier which is contained in a thermal field-flow fractionation channel depends on the cold wall temperature and on the temperature difference across the channel thickness. It is observed that the void time of the solvent peak decreases when increasing the average temperature in the channel. The void time is found to be directly proportional to the average carrier density in the channel. The determination of the void time from the knowledge of the channel geometrical volume and the measurement of the volumetric flow-rate leads to significant errors if the thermal expansion of the carrier between the temperature of the measurement and the average channel temperature is not taken into account. Recommendations are given for proper void time determinations in thermal FFF.