Search

BACKGROUND The aim of this study was to develop an efficient method for cholesterol oxide product (COP) determination in irradiated and non-irradiated ready-to-eat foods with high water content by gas chromatography–flame ionisation detector after accelerated solvent extraction (ASE), and derivatisation with a silylating reagent. RESULTS The ASE solvent was an 85:15 v/v petroleum ether/chloroform mixture at 40 °C and 1500 psi followed by solid phase extraction. The ASE method was compared with the established lixiviation method, proving an advantageous alternative which reduces analysis time by a factor of 15 and solvent volume by 50%, and minimises the use of chlorinated solvents. COP derivative structures were identified by gas chromatography coupled with mass spectrometry. Analytical characteristics were determined from standards and recoveries were 63–95%, establishing the validity of the method. CONCLUSION The results obtained and their analysis by chemometric techniques established COP formation in food samples after e-beam irradiation. Increase in COP concentration depended on both irradiation doses and food composition, mainly water and fat content, although linear correlations among variables were not found. © 2016 Society of Chemical Industry

A two-dimensional HPLC method for the simultaneous direct chiral enantiomeric determination of acid and ester IMI herbicides has been described. Difficulties arising from differences in polarity were overcome. Firstly, the imazaphyr, imazethapyr and imazamethabenz methyl herbicides were separated in a C18 achiral column. Then, their respective enantiomers were separated using a protein chiral AGPTM column; a heart-cut mode was used. Mobile phases of the two systems were compatibilized, after optimizing by factorial design using multiple response analysis. The proposed method has been validated by recovery studies from an enriched soil sample. Important enantiomer parameters such as enantioresolution higher than 1.12, enantiomeric ratio (ER) close to 1 and enantiomeric fraction (EF) around 0.5 were obtained for standards, confirming that herbicides are present as racemates.

Resumen Introduccion La anemia puerperal es un proceso tan presumiblemente frecuente como infraestimado. Se estima una prevalencia del 50% en las primeras 48 h. La mayoria se resuelve espontaneamente en la primera semana, pero en ocasiones pasa a ser una complicacion grave.Como objetivo del estudio nos planteamos identificar los factores asociados al padecimiento de bajos niveles de hemoglobina en el posparto en una cohorte de pacientes atendidas por proceso de parto en el Servicio de Obstetricia del Complejo Hospitalario de Jaen. Material y metodo Se ha realizado un estudio de corte transversal en una muestra aleatoria y representativa de las pacientes atendidas en nuestro centro por proceso de parto. La variable principal ha sido el nivel de hemoglobina (g/dl) entre las 24-36 h posparto, aceptando la definicion de anemia cuando la hemoglobina es menor de 12 g/dl. Resultados Los resultados fueron aplicados a un modelo asociativo del que se concluye que las cesareas y los partos instrumentales presentan niveles de hemoglobina menores que los partos eutocicos; que la ferroterapia durante el embarazo consigue mayores niveles de hemoglobina en el posparto y que las hemorragias severas o moderadas tambien disminuyen los niveles de hemoglobina. Conclusion Las principales medidas profilacticas del descenso anormal de hemoglobina en el posparto son el adecuado tratamiento y profilaxis (mediante ferroterapia) de la anemia en el tercer trimestre de embarazo, y la prevencion y terapia de los sangrados durante el parto y el puerperio inmediato.

The aim of this study was to verify the occurrence of the coffee berry borer, Hypothenemus hampei (Ferrari), and to evaluate the population fluctuation of the pest in the Brazilian Cerrado (Federal District). The study was conducted, between November 2014 and October 2015, at Embrapa Cerrados (Planaltina/DF, Brazil) in an irrigated conilon coffee production area. In November 2014, 120 samples (ten berries/sample) were collected from berries that had fallen on the ground from the previous harvest. Between November 2014 and October 2015, insects were collected weekly, using traps (polyethylene terephthalate bottles) baited with ethyl alcohol (98 GL), ethyl alcohol (98 GL) with coffee powder, or molasses. Between January and July 2015, samples were collected fortnightly from 92 plants (12 berries per plant). All samples were evaluated for the presence of adult coffee berry borers. Samples from the previous harvest had an attack incidence of 72.4%. The baited traps captured 4062 H. hampei adults, and showed no statistical difference in capture efficiency among the baits. Pest population peaked in the dry season, with the largest percentage of captured adults occurring in July (31.0%). An average of 18.6% of the collected berries was attacked by the borer and the highest percentage incidence was recorded in July (33.2%). Our results suggest that the coffee berry borer, if not properly managed, could constitute a limiting factor for conilon coffee production in the Brazilian Cerrado.

A high performance liquid chromatography direct chiral method for the determination of p- and m-im- azamethabenz-methyl (IMBM) enantiomers is described. The four isomers were separated using a protein chiral AGP TM column. Elution order was established by circular dichroism. Factorial design was employed for mobile phase optimization using a small number of experiments. The best experimental conditions were ACN/NH4Ac-HAc 60 mM (3/97) at a flow rate of 0.9 mL min -1 in isocratic mode, detection at 247 nm wavelength and 24 C temperature. Resolution up to 1.3 was obtained for the separation of the 4 IMBM enantiomers. The proposed method is useful to determine the p/m IMBM ratios and their respective enan- tiomers in samples containing the aforementioned herbicide. The p/m IMBM ratio was higher in the standard than in the sample. LOD values were between 0.15 and 0.43 mg L -1 and recoveries were higher than 93 %.

A study of the formation of 1cholesterol oxidation products (COPs) has been carried out in four 2ready-to-eat (RTE) foods (cooked ham, Spanish Serrano ham, minced beef, and soft cheese). The samples were previously treated with electron-beam irradiation between 1 and 8 kGy. Three COPs, 25-hydroxycholesterol, 7-ketocholesterol and 6-ketocholestanol, were extracted together with the lipid fraction using chloroform. Then, COPs were isolated by sample clean up using 3solid phase extraction (SPE) and were analyzed by 4high performance liquid chromatography with ultraviolet detection (HPLC-UV). Method validation was established by precision and recovery studies. Results showed that non-irradiated cheese and cooked ham samples did not contain COPs. In general, an increase in COP content was observed in all cases when the irradiation dose increased, although this increase was not linear. The 6-keto COP was not detected in any of the RTE food samples studied regardless of the irradiation dose.

Potential racemization of L-amino acids (AA) in ready-to-eat (RTE) cooked ham after hygienization by electron-beam irradiation between 1 and 8kGy was studied. An indirect chiral method based on the derivatization reaction of AA with o-phthaldialdehyde and N-acetyl-L-cysteine followed by reversed-phase HPLC and fluorimetric detection was applied to detect ten enantiomeric pairs of free AA (Asp, Ser, Thr, Ala, Tyr, Val, Trp, Phe and Leu). Five of the D-AA were not found in any of the samples analyzed; the other five remaining D-AA (D-Asp, D-Ser, D-Ala, D-Val and D-Leu) were detected both in irradiated and non-irradiated cooked ham samples, their content being in the range 1.25-13.79μg/g. Although significant differences appeared for a few of the samples and doses, no positive correlation between the D-AA content and the irradiation doses was observed. Therefore, the electron-beam irradiation technique could be useful for sanitation of packed RTE cooked ham at doses allowed by WHO and EU, since it remains chemically safe to eat.

An indirect chiral HPLC method based on the derivatization reaction with o-phthaldialdehyde and N-acetyl-L-cysteine and fluorimetric detection is applied to determine the enantiomeric purity of amino acids in pharmaceutical preparations. Three samples, vanim™ 14, tebetane, and tulgrasum were analized and their enantiomeric contents were determined. Sample preparation did not require cleanup. The validity of the method was established. The D-AA content is not always specified in the labels of these pharmaceutical preparations.

Table grapes were irradiated with UV nanosecond laser pulses in searching for resonant photo-elicitation of trans-resveratrol, a known antioxidant compound naturally produced by grapevines and other plants. To this end, the irradiation time as well as the wavelength dependence of the induced trans-resveratrol content was investigated by comparing the elicitation level of this compound at two laser wavelengths. One wavelength was selected right at the maximum of the absorption band (302.1 nm, the resonant wavelength for this compound) while the second was selected (300 nm, a non-resonant wavelength) such that trans-resveratrol absorption is negligible. It was found that the resonant irradiation enhances the resveratrol content in grapes by up to six times more than that of non-resonant irradiation, the rest of the conditions being the same. This work demonstrates how selective laser excitation of fruits can open new possibilities for the development of functional foods with enhanced nutritional and beneficial properties.

Diabetes & Metabolism - In Press.Proof corrected by the author Available online since lundi 25 juillet 2016

The indirect chiral method, based on the o-phthaldialdehyde reaction using the chiral N-acetyl-L-cysteine reagent, has been optimized to determine D-amino acids in milk and oyster samples. Both the derivatization reaction and the HPLC separation have been improved, and simple sample treatments were proposed. The milk sample preparation involved centrifugation and filtration through polytetrafluoroethylene filters for determination of free D-AA. Two methods, nonenzymatic and enzymatic, were applied to determination of free and total D-AA, respectively, in oyster samples. The D-AA contents were in the range of 0.14 to 4.32 mg/L for milk samples and 0.80 to 15.9 mg/g for oyster samples, with relative standard deviations lower than 10% (n = 4), except for D-Tyr. In general, mean recoveries were greater than 90% with relative standard deviations lower than 9% (n = 4) at concentration levels from 0.055 to 0.426 mg/L for milk samples and 0.348 to 1.10 mg/ g for oyster samples.

A gas chromatography with nitrogen–phosphorus detection direct method for methoxyurea herbicide determination in powdered potato and fresh potato samples has been developed. A previous study of the thermal stability of the phenylurea herbicides seems to confirm that the ones containing the methoxy radical, i.e. monolinuron, linuron and chlorbromuron, were stable. The herbicides were extracted from the sample through liquid–liquid extraction with dichloromethane–light petroleum (1:1), followed by solid-phase extraction in a C 8 cartridge. The recoveries were in the range 84–95% for powdered potato and 86–101% for fresh potato. The RSD values were less than 10%, at 0.1 μg g −1 concentration level ( n =4) for both types of samples. Detection limits of the method were 7.0–30 ng g −1 for powdered potato and 6.0–50 ng g −1 for fresh potato.

A series of esters derived from (±) 3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylic acid hydrochloride were synthesised and studied by NMR spectroscopy. The combined use of 1 H– 1 H COSY, NOESY and 1 H– 13 C correlation spectra of these compounds helped in the unambiguous assignments of the bicyclic carbon and proton resonances. The crystal structure of (±) 3-diphenylacetoxy-1-azabicyclo[2.2.2]octane-3-carboxylic acid hydrochloride was determined by X-ray diffraction.

A rapid method is proposed for the determination of 16 polycyclic aromatic hydrocarbons (PAH) in non-fatty food (mashed potato, potato and toasted bread samples) based on their extraction with ethyl ether-methylene chloride (1:1) by sonication, and subsequent separation by high-performance liquid chromatography (HPLC) with fluorimetric detection. A Hypersil Green PAH column was used with a gradient of acetonitrile-water as the mobile phase, together with a programme of ten excitation and emission wavelength pairs. At levels 1.60-2320 microg kg(-1), mean recoveries of PAH were in the range 70-86% for mashed potato, potato and toasted bread samples. The relative standard deviations were in the range 4.2-11% (n = 6). Total PAH found in mashed potato were in the range 9.35-17.1 microg kg(-1), in potato samples 8.47-17.2 microg kg(-1) and in toasted bread samples 7.38-18.0 microg kg(-1), with relative standard deviations in the range 0.8-12%. Only chrysene, determined in Ortiz toasted bread (7.38 microg kg(-1)), has carcinogenic properties.

Summary Human bocavirus (HBoV) plays a non-insignificant role as a pathogen in respiratory tract diseases in the pediatric population, especially in infants younger than 2 years of age. In this paper, we have described two cases of a possible nosocomial infection in a neonatal intensive care unit being HBoV the sole detected respiratory virus in clinical samples.

The study was undertaken to test the endothelium-mediated vascular responses in rats rendered hypertensive by chronic administration of 1,3-dipropyl-8-sulphophenylxanthine (DPSPX). The relaxant effect of carbachol (an endothelium-dependent relaxing drug) and of sodium nitroprusside (an endothelium-independent relaxing drug) as well as the potentiation of the contractile effect of noradrenaline by NG-nitro-l-arginine methyl ester (l-NAME) were compared in aortic rings from normotensive and DPSPX-hypertensive rats. Carbachol and sodium nitroprusside caused concentration-dependent relaxations in aortic rings precontracted by 1 μM noradrenaline. The relaxant effect of carbachol was significantly reduced in tissues of DPSPX-hypertensive rats: the maximal relaxant effect being 86 ± 3% and 64 ± 4% (of the pre-existing tone) in normal and hypertensive rats, respectively, while there were no significant differences in the relaxant effect of sodium nitroprusside. l-NAME (100 μM) significantly reduced the EC50 values of noradrenaline (3.71 ± 0.28 times, n = 8 and 2.96 ± 0.27 times, n = 7, in normal and hypertensive rats, respectively) and significantly enhanced the maximal contractile effect of noradrenaline (46 ± 8%, n = 8 and 35 ± 6%, n = 7, in normal and hypertensive rats respectively): the factors of reduction of EC50 values and the percentages of enhancement of the maximal contractile effect in the aorta of normal and hypertensive rats were not significantly different. The results obtained provide evidence of functional impairment of the endothelium in DPSPX-hypertensive rats.

1. This investigation was undertaken to determine the existence of pre- and postjunctional effects of 5-hydroxytryptamine (5-HT) in the cephalic vein of newborn dogs. For the sake of comparison, some experiments were also carried out on the veins of adult animals. 2. 5-HT reduced, in a concentration-dependent manner the overflow of tritium evoked by electrical stimulation of tissues previously loaded with 3H-noradrenaline for the same range of concentrations (0.01-1 microM 5-HT) in both neonates and adults. The maximal reduction of tritium overflow caused by 5-HT was 36 +/- 6% and 77 +/- 5% (n = 4; P < 0.001) in neonates and adults, respectively. 3. Postjunctionally, 5-HT caused concentration-dependent contractions of vessels from both neonates and adults and its EC50 values were not significantly different at the two ages. The maximal effect of 5-HT was smaller in newborn (0.69 +/- 0.03 g/mg) than in adult (1.16 +/- 0.06 g/mg) animals (n = 9; P < 0.01). 4. Metitepin antagonized 5-HT effects while ketanserin was ineffective, both pre- and postjunctionally, in newborn and adult dogs. 5. It is concluded that there are 5-HT receptors at pre- and postjunctional level at birth and that these receptors probably belong to the 5-HT1 type.

A flow-injection method is proposed for the simultaneous determination of o - and p -nitrophenol. It is based on formation and extraction of ion pairs using tetrabutylammonium as counter ion at pH 7.4 and diode-array spectrophotometric detection at 260 and 410 nm for o - and p -nitrophenol, respectively. The calibration graphs were linear from 0.1 to 12 mg 1 −1 , the relative standard deviation ( n = 8) at 6 mg 1 −1 was 0.15% for both o - and p -nitrophenol and the detection limits were 0.03 mg 1 −1 .

A multivariate-multicomponent analysis method for the determination of chlorophenols by diode array derivative spectrophotometry is proposed. The method is based on extraction of chlorophenols directly or as ion pairs with tetrabutylammonium as the counterion in chloroform at pH 9.1. Prediction and quantitative determinations (within the concentration range 3.0–15.0 mg liter−1) of two-, three-, and four component mixtures were possible using multivariate calibration of first-derivative spectra and a multicomponent analysis computer program based on least-squares regression.

An electron microscopic study has been performed of the morphological changes in PbS and Ag2S crystals during their growth by the silica gel technique in different inorganic acidic gel media using U-tubes. The formation and growth of the PbS and Ag2S crystals were followed by a binocular lens and an optical microscope. The morphological changes of the PbS crystals obtained in an HCl gel medium were the same as those observed for the Ag2S crystals in HClO4 and HNO3 gels. The sequence began with the formation of single crystals showing dendritic growth, and was followed by growth along the [100] direction. The changes were remarkably different for PbS crystals obtained in HClO4 and HNO3 gel media. Whereas the first steps also involved the formation of dendritic crystals, subsequently the crystals grew along [111]. Therefore, morphological changes are due to different nucleus formation and growth rates, which depend on the nature and concentration of the acidic medium. The most perfect cubic structure is obtained for the slowest rate.These changes were confirmed by electron microscopy, and the compounds obtained were identified by X-ray diffraction. Using these techniques it was observed that PbS and Ag2S crystals grew independently in gels which diffused thioacetamide and a mixture of Pb and Ag ions, instead of yielding PbS-containing AgI ions as an impurity.

The usefulness of the potassium tert-butoxide/dimethyl sulphoxide/ethyl iodide reaction with carbamate and phenylurea herbicides, and its application to phenoxy acids as a way to prevent hazards and toxicity of the sodium hydride/dimethyl sulphoxide/methyl iodide reaction was studied. Using factorial design optimization of this reaction was carried out. A solid-phase extraction method using dimethyl sulphoxide as eluent on-line with this reaction was developed to determine these herbicides in water samples by gas chromatography-mass spectrometry. Relative standard deviation values were lower than 10% for most of the herbicides in multicomponent trace determinations. Detection limits were in the 0.110-0.652 ng L(-1) concentration range. The validity of the method was confirmed by recovery studies from natural water samples.

A FIA method is proposed for the determination of non-ionic surfactants, applying spectrophotometric detection. The method is based on the formation of a “surfactant-K+-picrate” adduct and subsequent extraction into 1,2-dichloroethane. The method can handle samples containing large excesses of ionic and amphoteric surfactants, which are retained on ion-exchange columns inserted in the flow system. Beer's law is obeyed at 380 nm in the 0.02–1.2 mg·l−1 range for Triton-type non-ionic surfactants (X-100, X-405 and WR-1339). Relative standard deviation (n=10) is 0.3% at the 0.5 mg·l−1 level. The method has been applied to several samples and its applicability evaluated by ANOVA statistical comparison with two other methods.

Objective To our knowledge, none of the articles has been published in the literature which analyse the alterations of saliva in different stages of chronic renal failure (CRF). The objective of this study has been to analyse the flow, pH and biochemical composition of saliva in patients with moderate–severe CRF (M–S CRF) and with terminal renal failure (TRF). Design The study group was formed of 50 CRF patients: 22 with M–S CRF and 28 with TRF included in a haemodialysis programme. A control group with similar characteristics was established (n = 64). Saliva samples were taken from both patients and controls to determine the salivary pH and biochemical composition. Results Whole salivary flow was similar in patients and controls. Salivary concentrations of creatinine, urea, sodium, potassium, chloride and alpha-amylase were significantly higher in patients than in controls. Calcium concentration was significantly lower in patients than in controls. Creatinine, urea and potassium concentrations were significantly higher in patients with M–S CRF than in those with TRF. The salivary pH was significantly higher in patients than in controls. Conclusions Salivary composition in patients with CRF is conditioned by the stage of renal failure. The relationship between these biochemical parameters and the oral health status has still not been definitively clarified.

Biological therapies have transformed the paradigm of treatment of several inflammatory rheumatic diseases such as rheumatoid arthritis, spondyloarthritis, vasculitis or systemic lupus, among others. Since the first TNF antagonists, numerous molecules targeting other immune pathways (IL-1, IL-6, IL-17, IL-12/IL-23, B Lymphocytes and co-stimulation) have become broadly available and the use of biologics is increasing worldwide. Nevertheless, blocking and neutralizing major pro-inflammatory pathways, depleting B-cells and interfering with T-cell function lowers the threshold for infections. In fact, patients on biologics are at higher risk of infectious complications, including serious infections and rare opportunistic infections. This risk is not the same for all biologics, nor for all patients, and it represents a real issue that clinicians should be aware of, recognize promptly and anticipate whenever appropriated. This lecture aims to provide an overview of current knowledge on the infectious risk associated with the use of biologics, in particular of viral infections. Importantly, preventive strategies will be addressed. Disclosure of Interest None declared

A deep revision of the carbamate methyl derivatization reaction with sodium hydride/dimethyl sulfoxide/methyl iodide was carried out. Representative carbamates, R(1)-NH-COO-R(2), mainly N-methyl and N-aryl ones, have been studied in order to clarify which carbamates undergo this reaction. Two possible reaction routes are proposed; the route depends on the carbamate substituent (-OR(2) group) more than on the methyl or aryl groups joined to the NH moiety as literature indicates. The classification of carbamates in N-methyl and N-aryl is not suitable to predict the methylation pathway. A laboratory-made closed reactor allows handling the reagents involved, minimizing hazards and simplifying the procedure for rapid analysis.

Chitinolytic activity in the supernatant from autolysed cultures or Penicillium oxalicum in different media was studied. Chitinase and β-N-acetylglucosaminidase activities were detected in culture fluids when the carbon source in the medium was exhausted. The highest β-N-acetylglucosaminidase activities appeared in the media containing glucose and supplemented with colloidal chitin (6 g l −1 ) and trace elements. The highest chitinase activities appeared in media containing glucose and supplemented with N-acetylglucosamine or colloidal chitin (2 g l −1 ). The β-N-acetylglucosaminidase had a pH optimum at 4.5 and chitinase at 6.5

Background Many patients with a clinical diagnosis of Systemic lupus erythematosus (SLE) do not fulfill the ACR 1997 classification criteria (ACR997). Consequently, patients included in SLE studies might not be representative of the real spectrum of the disease. The new SLICC 2012 classification criteria (SLICC912) were proposed to improve the sensitivity of SLE classification. However, these criteria require external validation. Objectives To compare the sensitivity for SLE diagnosis of the ACR997 and SLICC912 classification criteria sets in a real life, multicenter, international SLE population. Methods We included in this cross-sectional observational study all patients with a clinical diagnosis of SLE followed at the participating Rheumatology centers and registered in the Portuguese and Spanish national registries (Reuma.pt and RELESSER, respectively). For each patient, we evaluated the fulfillment of the ACR997 and SLICC912 criteria. The sensitivity for SLE diagnosis of each classification set was calculated. We compared the proportion of cases fulfilling ACR997 and SLICC912 using the McNemar9s test. To compare dichotomous variables in two independent populations, we applied a Chi-square or Fisher9s exact test, as appropriate. The statistical significance level was p Results We included 2055 SLE patients (female = 91.4%; Caucasian =93.5%; age at disease onset = 33.1±14.4; age at SLE diagnosis = 35.3±14.7; age at SLE criteria scoring = 47.4±14.6) from 17 centers. The sensitivity for SLE diagnosis was higher with the SLICC912 (93.1%) compared with the ACR997 (85.6%) (p The sensitivity for SLE diagnosis increased with longer disease duration, for both the ACR997 and SLICC912 (p 20 years of disease. Conclusions In real-life clinical setting, the SLICC912 classification criteria present a higher sensitivity for SLE compared to ACR997. The SLICC912 might allow a SLE classification earlier in the disease course. Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.2506

As a result of thermal stability studies of carbamate pesticides, a method has been proposed for their direct determination by gas chromatography in the ranges 1-20 and 0.1-1 mg l(-1), using flame ionization and nitrogen-phosphorus detection, respectively. The method allows the determination of propham, propoxur, carbofuran, carbaryl, methiocarb, isopropoxyphenol and naphthol in powdered potato samples. The analytes were previously extracted with a light petroleum-dichloromethane (1:1, v/v) mixture and preconcentred by solid-phase extraction through a C8 cartridge. The recoveries obtained from spiked potato samples (n=4 replicates) at two concentration levels, 10 and 0.5 mg of pesticide per kg of sample, were in the ranges 72-115 and 50-73%, with relative standard deviations of 2-7 and 5-8%, respectively. The detection limits were 50-210 and 41-53 microg kg(-1) with flame ionization and nitrogen-phosphorus detection, respectively, and reaching the maximum residue levels, 0.05 mg kg(-1) for methiocarb and propoxur, set by the Real Decreto 280/1994 (based on the European directive).

A multicomponent analysis method is proposed for the determination of chlorophenols by diode array derivative spectrophotometry. The method is based on formation of ion-pairs with tetrabutylammonium as counterion and extraction in chloroform at pH 9.1. Quantitative determinations (within the 2–20 mg/l. concentration range) of two-, three- and four-component mixtures were possible, using the first derivative spectra and a least-squares computer programme.

A lead(II) selective electrode has been developed. This electrode is essentially formed by a lead wire, one end of which is coated with lead(II) diethyldithiocarbamate. The response is Nernstian for lead ions in a 10 −1 to 10 −5 M concentration range. The direct determination of this element and the indirect determination of several anions are possible.

The conventional spectrophotometric method for the determination of fluoride, based on the fluoride/lanthanum(III)/alizarin fluorine blue ternary complex, is improved by addition of sodium dodecyl sulphate. In 15% (v/v) acetone medium, the absorbance of the binary reagent complex is decreased and the reaction time is only 3 min under sonication. Beer's Law is obeyed at 574 nm for fluoride concentrations in the ranges 0.075–0.30 and 0.20–1.2 mg 1−1; the apparent molar absorptivities are (1.6 ± 0.1) × 104 and (1.5 ± 0.1) × 104 mol−1 cm−1 fluoride levels, respectively. This method is applied to the determination of fluoride in bottled mineral waters.

Favretto et al.'s method for the spectrophotometric determination of the non-ionic polyoxyethylenated surfactants Triton X-100, X-405 and WR-1339 was improved by the presence of ethanol. Extraction of the surfactant-K+-picrate adduct occurs instantaneously. Beer's law is obeyed in the range 0.02–1.0 p.p.m. The specific absorptivities range from 150 to 1540 l g–1 cm–1 and the detection limits lie between 5.0 p.p.b. and 0.05 p.p.m. The method was applied to the determination of these surfactants in milk and butter samples, the applicability being evaluated from recovery studies.