Embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate in patients with hemoptysis: A retrospective single-center study.

OBJECTIVES: To evaluate the safety and efficacy of the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate (NBCA) in patients with hemoptysis. METHODS: We analyzed a total of 55 consecutive patients with hemoptysis (14 mild, 31 moderate, and 10 massive) treated with the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate between November 2013 and January 2020. The main variables analyzed were the rates of technical success, of clinical success, of recurrence, and of complications. Statistics included a descriptive analysis and Kaplan-Meier survival curves. RESULTS: Embolization was a technical success in 55 (100%) and a clinical success in 54 (98.2%). During follow-up (mean, 23.8 months; interquartile range, 9.7-38.2 months), hemoptysis recurred in 5 (9.3%) patients. The nonrecurrence rate was 91.9% one year after the initial procedure and 88.7% two years and four years after the initial procedure. Minor complications related with the procedure occurred in 6 (10.9%); no major complications occurred. CONCLUSIONS: The embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate is safe and efficacious for controlling hemoptysis, resulting in low recurrence rates.

Phenological and seismological impacts on airborne pollen types: A case study of Olea pollen in the Region of Murcia, Mediterranean Spanish climate.

The rationale of this paper was to investigate whether earthquakes impact airborne pollen concentrations, considering some meteorological parameters. Atmospheric pollen concentrations in the Region of Murcia Aerobiological Network (Spain) were studied in relation to the occurrence of earthquakes of moment magnitude (up to Mw = 5.1) and intensity (intensity up to grade VII on the European Macroseismic Scale). In this study, a decade (2010-2019) was considered across the cities of the network. Earthquakes were detected in 12 out of 1535 days in the Olea Main Pollen Season in Cartagena, 49 out of 1481 days in the Olea Main Pollen Season in Lorca, and 39 out of 1441 days in the Olea Main Pollen Season in Murcia. The Olea pollen grains in this network were attributed to the species Olea europaea, i.e., the olive tree, a taxon that appears widely in the Mediterranean basin, in both cultivated and wild subspecies. Differences between the Olea concentration on days with and without earthquakes were only found in Lorca (Kruskal-Wallis: p-value = 0.026). The low frequency and intensity of the earthquakes explained these results. The most catastrophic earthquake felt in Lorca on May 11th, 2011 (IVII, Mw = 5.1, 9 casualties) did not result in clear variations in pollen concentrations, while meteorology (e.g., African Dust Outbreak) might have conditioned these pollen concentrations. The research should be broadened to other active seismological areas to reinforce the hypothesis of seismological impact on airborne pollen concentrations.

Embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate in patients with hemoptysis: a retrospective single-center study. / Embolización de arterias bronquiales y arterias sistémicas no bronquiales con n-butil-cianoacrilato en pacientes con hemoptisis: un estudio monocéntrico y retrospectivo.

OBJECTIVES: To evaluate the safety and efficacy of the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate (NBCA) in patients with hemoptysis. METHODS: We analyzed a total of 55 consecutive patients with hemoptysis (14 mild, 31 moderate, and 10 massive) treated with the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate between November 2013 and January 2020. The main variables analyzed were the rates of technical success, of clinical success, of recurrence, and of complications. Statistics included a descriptive analysis and Kaplan-Meier survival curves. RESULTS: Embolization was a technical success in 55 (100%) and a clinical success in 54 (98.2%). During follow-up (mean, 23.8 months; interquartile range, 9.7 - 38.2 months), hemoptysis recurred in 5 (9.3%) patients. The nonrecurrence rate was 91.9% one year after the initial procedure and 88.7% two years and four years after the initial procedure. Minor complications related with the procedure occurred in 6 (10.9%); no major complications occurred. CONCLUSIONS: The embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate is safe and efficacious for controlling hemoptysis, resulting in low recurrence rates.

Monitoring of pesticide residues in crops irrigated with reclaimed water by a multiresidue method based on modified QuEChERS.

In this study, we aimed to validate and apply a quick and easy extraction method for the simultaneous determination of 27 pesticide residues at trace levels in agricultural samples (soil, fruit, and leaf) to monitor the presence of these contaminants released from reclaimed water. The procedure was based on a salting-out extraction method with acidified acetonitrile, followed by a dispersive solid-phase extraction (d-SPE) clean-up step applying the C18 sorbent. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS) was used for identification and quantification of the target analytes. This methodology provided recovery values higher than 70%, for all pesticides and matrices evaluated in the study, except for propamocarb in soil samples (35%). Repeatability and reproducibility results, calculated as relative standard deviations (RSD, %), ranged between 1% and 18% in both cases. No remarkable matrix effects were observed for vegetable samples, except for thiamethoxam in red cabbage, and hexythiazox in carrot and leaves (between 30 and 40%). Soil samples showed a moderate matrix effect (between 21 and 35%) for more than 80% of the compounds. Monitoring pesticide residues found in agricultural samples irrigated with contaminated reclaimed water under controlled conditions revealed the efficacy of the proposed method. Three common vegetables were grown to evaluate the different migration and distribution rates in crops and soil. Pesticide accumulation in the different parts of the crop (soil, fruit, and leaves) and the potential human exposure to pesticides through daily intake were also discussed.

The effects of continentality, marine nature and the recirculation of air masses on pollen concentration: Olea in a Mediterranean coastal enclave.

Olea pollen concentrations have been studied in relation to the typology of air masses, pollen grain sources and marine nature during advections in a coastal enclave in the south-eastern Iberian Peninsula. Since Spain is the world's leading olive producer, and olive growing extends throughout the Mediterranean basin, this location is ideal for the study of long-distance transport events (LTD) during the main pollen season (MPS). The air masses were classified using the calculation of 48-h back trajectories at 250, 500 and 750 m above ground level using the HYSPLIT model. After that, the frequency of LDT events from Africa and Europe was found to be 8.7% of the MPS days. In contrast, regional air masses were found in 38.6% of the MPS days. This was reflected in pollen concentrations, with significantly higher concentrations (p-value <0.05) on days with regional air masses compared to days with European air masses. Regarding the source areas, the importance of nearby sources with intense olive cultivation was confirmed (i.e., Andalusia). This proximity was relevant beyond the attenuations observed when the advections acquired a marine nature as the air mass back trajectories moved over the sea (p-value <0.001). The review of air mass typologies, source areas and pollen concentrations resulted in establishing peak dates and the detection of LDT associated with these peak dates. Distortions in the typical path of each air mass explained alterations in pollen concentrations on consecutive days. The recirculation and loops of the air mass back trajectories varied the pollen load that every type of air mass could originally contain.

PTPN22 polymorphism is related to autoimmune disease risk in patients with Turner syndrome.

Individuals with Turner syndrome (TS) clearly have an increased risk for autoimmune diseases. Recently, an allelic variation (C1858T) of the PTPN22 gene was revealed to be associated with the development of autoimmunity. Thus, the aim of this study was to determine the frequency of the PTPN22 C1858T polymorphism in women with Turner syndrome (TS) compared to controls. Case-control study comprises 142 women with TS (cases) and 180 healthy and fertile women without a history of autoimmune disease (controls). Detection of the PTPN22 C1858T polymorphism (rs2476601) was performed by TaqMan real-time PCR. The chi-square test was used to compare allele and genotype frequencies between groups and to estimate the Hardy-Weinberg equilibrium. All P-values were two-tailed, and 95% confidence intervals (CIs) were calculated. A P-value <0.05 was considered statistically significant. Genotypes CC, CT and TT of the PTPN22 C1858T polymorphism presented frequencies of, respectively, 67.6%, 28.2% and 4.2% in the TS, and 82.8%, 16.1% and 1.1% in the control group (P = 0.0043). Alleles C and T were present in, respectively, 81.7% and 18.3% of the patients with TS (P = 0.001, OR = 2.22, 95% CI = 1.39-3.54) and in 90.8% and 9.2%, respectively, of the controls. The data suggest that in Brazilian patients with TS, the PTPN22 C1858T polymorphism may be an important genetic factor predisposing to autoimmune disease risk.

Solid phase extraction of pesticides from environmental waters using an MSU-1 mesoporous material and determination by UPLC-MS/MS.

This paper describes the synthesis of a silica based MSU-1 mesoporous solid and its application as sorbent in solid-phase extraction to pre-concentrate thirteen pesticides of low-high polarity (methomyl, cymoxanil, carbofuran, monolinuron, isoproturon, methidathion, methiocarb, malathion, phosalone, diazinon, penconazole, neburon and chlorotoluron) in ground and river water. The synthesis was based in an H-bonding interaction assembling (I0N0) between two non-ionic components (the inorganic silica surface, I0 and the polyethylene oxide template, N0) by adding tetraethoxysilane to the non-ionic surfactant Brij®100, the latter previously dissolved in HCl 1 M. 50 mL water samples adjusted at pH= 3.5 were passed, at a flow rate of 5 mL/min, through a home-made cartridge containing 50 mg of MSU-1 sorbent, pre-conditioned with 5 mL of ultrapure water; then, the cartridge was washed with 5 mL of ultrapure water. Following elution with 5 mL of acetonitrile, the pesticides were determined by ultra performance liquid chromatography coupled to triple quadrupole-mass spectrometry. Two selected reaction monitoring transitions were monitored per compound, the most intense one being used for quantification and the second one for confirmation. Three points were used for identification, as established in the Directive 96/23/EC for LC-MS/MS analysis, which deals with confirmatory methods for organic residues and contaminants listed in the Group B (veterinary drugs and contaminants). Medium matrix effect (|20%||50%|). Therefore, the standard addition methodology was applied by adding an adequate amount of the pesticide standard mixture to the final sample extract. All pesticides were quantified using this approach for practical reasons, thus avoiding two different calibrations. The method quantification limit (MQL) of pesticides was 0.01 µg/L for all of them, except for diazinon (0.1 µg/L). Recoveries of the target pesticides at MQL and 0.25 µg/L concentration levels in blank river water were in the range 70.1-113.5% and 86.7-107.3%, respectively, with RSDs lower than 16.3% and 15.7%, respectively. Four ground water samples and three river water samples, taken from Almería (Spain), were analyzed by the proposed method and only phosalone at a concentration level of 0.05 µg/L was found in one river water sample.

Group Psychotherapy Could Improve Depression in Cirrhotic Patients on the Liver Transplant Waiting List.

BACKGROUND: It is well-known that there is a high incidence of depression in patients on the liver transplant (LT) waiting list. However, there have been few studies of psychological intervention on these patients. OBJECTIVES: To determine symptoms of depression in patients on the LT waiting list and the impact of group psychotherapy. METHODS: Study population: patients on the LT waiting list who received group psychotherapy (n = 15). CONTROL GROUP: patients who did not receive psychotherapy (n = 10). Measurement instrument: Beck's depression test, which was provided before psychotherapy was initiated and after it was completed (after 6 months). The control group was given the questionnaire at the same 2 points in time as the study group. The psychotherapeutic method consisted of discussing patients' feelings, which dealt with several matters related to transplantation. Different coping strategies were considered. RESULTS: More than half of those surveyed initially had depressive symptoms. When the second survey was administered to the study population, all the patients improved in their psychopathological assessment. When the survey was administered to the control group, a worse psychopathological assessment was obtained in all cases. CONCLUSIONS: Our data suggest an improvement in depressive symptoms in patients on the LT waiting list after receiving group psychotherapy.

Application of solid-phase microextraction for determination of pyrethroids in groundwater using liquid chromatography with post-column photochemically induced fluorimetry derivatization and fluorescence detection.

Solid-phase microextraction (SPME) is a rapid and simple analytical technique which uses coated fused-silica fibers to extract analytes from aqueous samples. This study develops a method of SPME analysis for seven pyrethroids, including fenpropathrin, lambda-cyhalothrin, deltamethrin, fenvalerate, permethrin, tau-fluvalinate and bifenthrin in groundwater samples using high performance liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection (SPME-LC-PIF-FD). To perform the SPME, a 60 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used for the extraction of the pesticides from groundwater samples. The main factors affecting the SPME process, such as extraction time, stirring rate, extraction temperature, pH and the desorption process were studied. The use of photochemically induced fluorescence for detection improved sensitivity and selectivity. The limits of quantification (LOQs) obtained in the matrix, with respect to EURACHEM Guidance, varied between 0.03 and 0.075 microgL(-1). Relative recoveries ranged from 92 to 109% and relative standard deviations values ranged from 2 to 9%.

Chemometric assisted solid-phase microextraction for the determination of anti-inflammatory and antiepileptic drugs in river water by liquid chromatography-diode array detection.

In the present work, an analytical method for the simultaneous determination of seven non steroidal anti-inflammatory drugs (naproxen, ketoprofen, diclofenac, piroxicam, indomethacin, sulindac and diflunisal) and the anticonvulsant carbamazepine is reported. The method involves preconcentration and clean-up by solid-phase microextraction using polydimethylsiloxane/divinylbenzene fibers, followed by liquid chromatography with diode array detection analysis. Parameters that affect the efficiency of the solid-phase microextraction step such as soaking solvent, soaking period, desorption period, stirring rate, extraction time, sample pH, ionic strength, organic solvent and temperature were investigated using a Plackett-Burman screening design. Then, the factors presenting significant positive effects on the analytical response (soaking period, stirring rate, stirring time) were considered in a further central composite design to optimize the operational conditions for the solid phase microextraction procedure. Additionally, multiple response simultaneous optimization by using the desirability function was used to find the optimum experimental conditions for the on-line solid-phase microextraction of analytes in river water samples coupled to liquid chromatography and diode array detection. The best results were obtained using a soaking period of 5 min, stirring rate of 1400 rpm and stirring time of 44 min. The use of solid-phase microextraction technique avoided matrix effect and allowed to quantify the analytes in river water samples by using Milli-Q based calibration graphs. Recoveries ranging from 71.6% to 122.8% for all pharmaceuticals proved the accuracy of the proposed method in river water samples. Method detection limits were in the range of 0.5-3.0 microgL(-1) and limits of quantitation (LOQs) were between 1.0 and 4.0 microgL(-1) for pharmaceutical compounds in river water samples. The expanded uncertainty associated to the measurement of the concentration ranged between 8.5% and 29.0% for 20 microgL(-1) of each analyte and between 9.0% and 29.5% for the average of different concentration levels. The main source of uncertainty was the calibration step in both cases.

Solving matrix effects exploiting the second-order advantage in the resolution and determination of eight tetracycline antibiotics in effluent wastewater by modelling liquid chromatography data with multivariate curve resolution-alternating least squares and unfolded-partial least squares followed by residual bilinearization algorithms II. Prediction and figures of merit.

A new powerful algorithm (unfolded-partial least squares followed by residual bilinearization (U-PLS/RBL)) was applied for first time on second-order liquid chromatography with diode array detection (LC-DAD) data and compared with a well-known established method (multivariate curve resolution-alternating least squares (MCR-ALS)) for the simultaneous determination of eight tetracyclines (tetracycline, oxytetracycline, meclocycline, minocycline, metacycline, chlortetracycline, demeclocycline and doxycycline) in wastewaters. Tetracyclines were pre-concentrated using Oasis Max C18 cartridges and then separated on a Thermo Aquasil C18 (150 mm x 4.6mm, 5 microm) column. The whole method was validated using Milli-Q water samples and both univariate and multivariate analytical figures of merit were obtained. Additionally, two data pre-treatment were applied (baseline correction and piecewise direct standardization), which allowed to correct the effect of breakthrough and to reduce the total interferences retained after pre-concentration of wastewaters. The results showed that the eight tetracycline antibiotics can be successfully determined in wastewaters, the drawbacks due to matrix interferences being adequately handled and overcome by using U-PSL/RBL.

Solving matrix-effects exploiting the second order advantage in the resolution and determination of eight tetracycline antibiotics in effluent wastewater by modelling liquid chromatography data with multivariate curve resolution-alternating least squares and unfolded-partial least squares followed by residual bilinearization algorithms I. Effect of signal pre-treatment.

The effect of piecewise direct standardization (PDS) and baseline correction approaches was evaluated in the performance of multivariate curve resolution (MCR-ALS) algorithm for the resolution of three-way data sets from liquid chromatography with diode-array detection (LC-DAD). First, eight tetracyclines (tetracycline, oxytetracycline, chlorotetracycline, demeclocycline, methacycline, doxycycline, meclocycline and minocycline) were isolated from 250 mL effluent wastewater samples by solid-phase extraction (SPE) with Oasis MAX 500 mg/6 mL cartridges and then separated on an Aquasil C18 150 mm x 4.6mm (5 microm particle size) column by LC and detected by DAD. Previous experiments, carried out with Milli-Q water samples, showed a considerable loss of the most polar analytes (minocycline, oxitetracycline and tetracycline) due to breakthrough. PDS was applied to overcome this important drawback. Conversion of chromatograms obtained from standards prepared in solvent was performed obtaining a high correlation with those corresponding to the real situation (r2 = 0.98). Although the enrichment and clean-up steps were carefully optimized, the sample matrix caused a large baseline drift, and also additive interferences were present at the retention times of the analytes. These problems were solved with the baseline correction method proposed by Eilers. MCR-ALS was applied to the corrected and uncorrected three-way data sets to obtain spectral and chromatographic profiles of each tetracycline, as well as those corresponding to the co-eluting interferences. The complexity of the calibration model built from uncorrected data sets was higher, as expected, and the quality of the spectral and chromatographic profiles was worse.

Novel Mapping Method for the Intraoperative Neurophysiologic Monitoring of Sexual Function During Prostate Surgery.

PURPOSE: The occurrence of urinary incontinence and erectile dysfunction after surgical treatment for prostate cancer is a significant and lingering problem. The aim of this study is to revise and improve older techniques of intraoperative cavernous nerve mapping already in use to improve accuracy and reliability. METHODS: We prospectively studied this technique in 12 patients suffering from prostate cancer. Inhalation or intravenous anesthetic regimen was used with nondepolarizing muscle relaxants. Stimulation protocol was 30 Hz, 0.2 ms, 10 to 20 mA intensity and a maximum duration of 30 seconds. Recording was performed with a system for measuring pressure changes using a stainless steel needle electrode inside the cavernous bodies. Stimulation was systematically performed at three distinct moments during the surgery at various points. An increase or decrease in pressure of 4 cm of H20 in the cavernous bodies was considered a positive result and negative response when no changes occurred after 30 seconds of continuous stimulation. RESULTS: Of patients, 91.6% had positive responses to initial stimulation. The anesthetic regimen did not appear to significantly influence the responses in our series. CONCLUSIONS: In light of the results of this study, the stimulation of the cavernous nerves may be a viable technique in the right context, which includes good patient selection (young patients with a localized tumor and with preserved potency). The major limitation is that mapping techniques are useful to localize functional nerves, but not to monitor function in a continuous manner.

Analysis of airborne Olea pollen in Cartagena (Spain).

Olive cultivation is of great importance in Southern Europe but olive pollen is the leading cause of allergy in many regions where it is grown. The best preventive measure for allergic patients is to avoid exposure. Thus, aerobiological monitoring networks must supply realistic pollen classes for the different types of allergic pollen. Even though those pollen classes are defined, they do not necessarily fit local data. Altogether, they should use predictive models to assess flowering intensity in advance. In this study, the Olea pollen degree of exposure classes (OPDEC) are defined based on percentiles and a predictive model is suggested for Cartagena, Spain. 24year (1993-2016) Olea pollen counts series was used to characterize the Main Pollen Season (MPS). The aerobiological samples were processed following the methodology proposed by Hirst and developed by the Spanish Aerobiology Network. The aerobiological database was completed with the meteorological data supplied by AEMET (Spanish State Meteorological Agency). MPS evolution over time, and its relation with temperature and rainfall, has been analysed. The study showed an increase in MPS duration and the amount of Olea pollen grains collected both in MPS and the peak day. The OPDEC should fit local data to improve preventive measures. Based on the 24year series, the proposed OPDEC for Cartagena are: Low (≤10grains/m3), Medium (between 10 and 50grains/m3), High (between 51 and 100grains/m3) and Very High (≥100grains/m3). Olea pollen estimations in the MPS and in the peak day were obtained by means of three Regression Methods and climatic factors. The analysis reveals that the Bagging for Regression Trees (BRT) method is a good predictive alternative and stablishes the importance for each meteorological variable.

Quality of Life and Group Psychological Intervention in Patients With Cirrhosis on Liver Transplant Waiting List.

BACKGROUND: The patients on the liver transplant (LT) waiting list usually present with deterioration in their quality of life. Previous studies on psychological intervention have shown how the quality of life can be improved. OBJECTIVE: To analyze preliminary results of the influence of group psychotherapy on the quality of life of patients on the LT waiting list. METHOD: Fifteen patients on the LT waiting list who accepted receiving group psychotherapy were selected. The development of each 1 of these sessions was carried out at fortnightly periods for 6 months (12 sessions). Those patients who received a transplant and those patients who did not attend more than 6 group psychotherapy sessions were excluded. The Nottingham Health Profile was used to assess the quality of life. It consists of 38 items belonging to 6 health dimensions: energy, pain, physical mobility, emotional reaction, sleep, and social isolation. The study population was given a questionnaire before starting group psychotherapy and after it was finished. RESULTS: Of the 15 patients selected from the study population, 3 patients were given a transplant before the psychotherapy had finished, and 5 patients were excluded for not having attended more than 50% of the sessions. Therefore, the study was completed on 7 patients (n = 7). Overall, a better assessment can be seen in the second questionnaire. CONCLUSIONS: Group psychotherapy might favorably influence the quality of life of patients on the LT waiting list; therefore, it might be interesting to carry out studies on a larger scale in order to confirm these results.

A Multicentric Brazilian Investigative Study of Copy Number Variations in Patients with Congenital Anomalies and Intellectual Disability.

Genomic imbalances are the most common cause of congenital anomalies (CA) and intellectual disability (ID). The aims of this study were to identify copy number variations (CNVs) in 416 patients with CA and ID from 5 different genetics centers within 4 different states by using the Multiplex Ligation-dependent Probe Amplification (MLPA) technique and to apply the chromosomal microarray (CMA) methodology in selected cases. The samples were analyzed by MLPA kits P064, P036, P070 and P250. Positive results were found in 97/416 (23.3%) patients. CMA was applied in 14 selected cases. In 6/14 (42.85%) patients, CMA detected other copy number variations not detected by the MLPA studies. Although CMA is indispensable for genotype refinement, the technique is still unfeasible in some countries as a routine analysis due to economic and technical limitations. In these cases, clinical evaluation followed by karyotyping and MLPA analysis is a helpful and affordable solution for diagnostic purposes.

Column switching liquid chromatography and post-column photochemically fluorescence detection to determine imidacloprid and 6-chloronicotinic acid in honeybees.

The determination of imidacloprid and its main metabolite (6-chloronicotinic acid) in honeybees was performed by liquid chromatography with post-column photochemical derivatisation in alkaline medium and fluorescence detection. The compounds were extracted from honeybees with acetone under ultrasound conditions prior to liquid-liquid partition with dichloromethane. The separation of extract components was performed using a 50 mm x 4.6 mm i.d. short column packed with 5 microm Aquasil C(18) using an acetonitrile:water gradient program as mobile phase. Injection of samples in 0.1 mol L(-1) H(3)PO(4)/KH(2)PO(4) buffer solution (pH 3) improved the chromatographic separation between the most polar components of matrix and the 6-chloronicotinic acid. Matrix components were removed to waste using an on-line clean-up method previously to post-column reaction. Limits of quantification were 0.3 and 5.0 microg L(-1) (corresponding to 1.2 and 20.0 microg kg(-1) in the honeybee sample) for imidacloprid and 6-chloronicotinic acid, respectively. The recovery was ranged from 80.2 to 91.7% with a relative standard deviation lower than 9.0%.

Determination of photoirradiated tetracyclines in water by high-performance liquid chromatography with chemiluminescence detection based reaction of rhodamine B with cerium (IV).

A simple, selective and sensitive method has been developed for the simultaneous determination of tetracycline, oxytetracycline, chlorotetracycline, demeclocycline, doxycycline and meclocycline based on reversed-phase high-performance liquid chromatography with chemiluminescence detection. The procedure was based on the chemiluminescent enhancement by photoirradiated tetracyclines of the cerium (IV)-rhodamine B system in sulphuric acid medium. The six tetracyclines were separated on an Aquasil-C18 column with a gradient elution using a mixture of acetonitrile and 0.1 mol L(-1) phosphate buffer as mobile phase, photoderivatized using a photoreactor consisting of a tube reactor coil of PFA and a 8W Xenon lamp. Under the optimized conditions, the method was validated with respect to linearity, precision, limits of detection and quantification and accuracy. The relative standard deviation (RSD) on intra-day precision was below 10% and detection limits ranged between 0.12 and 0.34 microg L(-1). The proposed method has been successfully applied to the determination of tetracyclines in surface water samples. A possible mechanism of the chemiluminescence in the system is discussed.

Determination of nine pyrethroid insecticides by high-performance liquid chromatography with post-column photoderivatization and detection based on acetonitrile chemiluminescence.

An HPLC method was developed to determine pyrethroids, including fenpropathrin, beta-cyfluthrin, lambda-cyhalothrin, deltamethrin, fenvalerate, permethrin, acrinathrin, tau-fluvalinate, and bifenthrin, by coupling HPLC, post-column irradiation with UV light and chemiluminescence detection of the resulting photoproducts. It is based on the observation that photolyzed pyrethroids take part in a chemiluminescent reaction in presence of K3Fe(CN)6 and NaOH, whose signal increases with the percentage of acetonitrile in the reaction medium. As the yield of the photoderivatization process and the chemiluminescent signals depend on the percentage of acetonitrile, the chromatographic column (a Gemini C18, Phenomenex 150 mm x 4.6 mm, 5 microm particle size) was chosen with the aim of using high percentages of this organic solvent in the mobile phase. Previous studies showed that the rate of the chemiluminescent reaction was very fast. Therefore, a modification was carried out in the detector in order to mix the analytes and reactives as near as possible to the measure cell. The optimised method was validated with respect to linearity, precision, limits of detection and quantification accuracy. Under the optimised conditions, linear working range extends three orders of magnitude with the relative standard deviation on intra-day precision below 10% and detection limits between 0.013 and 0.049 microg mL(-1), according to the compound. The proposed method has been successfully applied to the determination of pyrethroids in tomato with good results.

Determination of benzoylureas in ground water samples by fully automated on-line pre-concentration and liquid chromatography-fluorescence detection.

An on-line pre-concentration method for the analysis of five benzoylureas (diflubenzuron, triflumuron, hexaflumuron, lufenuron and flufenoxuron) in ground water samples was evaluated using two C(18) columns, and fluorescence detection after photochemical induced fluorescence (PIF) post-column derivatization. The trace enrichment was carried out with 35 mL of ground water modified with 15 mL of MeOH on a 50 mm x 4.6 mm I.D. first enrichment column (C-1) packed with 5 microm Hypersil Elite C(18). Retention properties of pesticides and humic acids usually contained in ground water were studied on C-1 at concentration levels ranging between 0.04 and 14.00 microg/L in water samples. The results obtained in this study show that the pesticides are pre-concentrated in the first short column while the humic acids contained in the ground water samples are eluted to waste. Pesticides recoveries ranged between 92.3 and 109.5%. The methodology proposed was used to determine benzoylureas in ground water samples at levels lower than 0.1 microg/L (maximum levels established by the European Union).