Soporte telemático de autogestión para pacientes con apnea obstructiva del sueño en tratamiento con CPAP: aspectos metodológicos y resultados preliminares del ensayo clinico telesas / Telematic self-management support for patients with obstructive sleep apnea under CPAP treatment: methodological aspects and preliminary results of the telesas clinical trial

Objetivo: Comprobar si un programa de telemedicina mejora el cumplimiento con CPAP, alcanzando un uso de, al menos, 4 horas al día en el 90% de los pacientes. Realizamos un estudio piloto para comprobar la viabilidad de un proyecto multicéntrico en el que perfeccionaremos dicho programa. Metodología: Pacientes con AOS severa poco sintomáticos en tratamiento con CPAP fueron randomizados a seguimiento habitual o seguimiento habitual más un programa de telemedicina durante 6 meses. Dentro de este programa, las variables de telemonitorización, la aparición de efectos secundarios y la presencia de sueño reparador eran analizadas para generar alarmas e instrucciones al paciente para la autogestión precoz de los problemas presentados con la CPAP. Resultados: 60 pacientes fueron randomizados, 33 al grupo intervención y 27 al grupo control, sin diferencias significativas en las variables basales. El 80% eran hombres con un rango de edad entre los 24 y 75 años. Solo hubo un abandono en el grupo control. Conclusiones: El uso de nuestro programa de telemedicina no ha supuesto ningún problema para los pacientes incluidos a pesar de la horquilla amplia de edad, siendo viable el desarrollo de un estudio a mayor escala con una herramienta de telemedicina perfeccionada. (AU)

Basis: poor compliance with CPAP is a problem at a clinical and research level, assuming the expected results are not achieved. The benefits of using telemedicine in obstructive sleep apnea (OSA) are inconclusive, with its positive effect on compliance being the most consistent in the literature. Objective: to check if a telemedicine program improves compliance with CPAP, reaching use of at least 4 hours a day in 90% of patients. We carried out a pilot study to verify the viability of a multicenter project in which we will perfect this program. Method: patients with severe OSA with few symptoms on CPAP treatment were randomized to usual follow-up or usual follow-up plus a telemedicine program for 6 months. Within this program, the telemonitoring variables, the appearance of side effects and the presence of restorative sleep were analyzed to generate alarms and instructions to the patient for early self-management of the problems presented with CPAP. Preliminary results: 60 patients were randomized, 33 to the intervention group and 27 to the control group, with no significant differences in the baseline variables. 80% were men with an age range between 24 and 75 years. There was only one dropout in the control group. Conclusions: the use of our telemedicine program has not posed any problems for the included patients despite the wide age range, making it feasible to develop a larger-scale study with an improved telemedicine tool. (AU)

Sumario de las recomendaciones y puntos clave del Consenso de las Sociedades Científicas Españolas (SEPAR, SEMICYUC, SEMES; SECIP, SENeo, SEDAR, SENP) para la utilización de la ventilación no invasiva y terapia de alto flujo con cánulas nasales en el paciente adulto, pediátrico y neonatal con insuficiencia respiratoria aguda grave / Summary of recommendations and key points of the consensus of Spanish scientific societies (SEPAR, SEMICYUC, SEMES; SECIP, SENEO, SEDAR, SENP) on the use of non-invasive ventilation and high-flow oxygen therapy with nasal cannulas in adult, pediatric, and neonatal patients with severe acute respiratory failure

El soporte respiratorio no invasivo (SRNI) comprende 2 modalidades de tratamiento, la ventilación mecá-nica no invasiva (VMNI) y la terapia de alto flujo con cánulas nasales (TAFCN) que se aplican en pacientes adultos, pediátricos y neonatales con insuficiencia respiratoria aguda (IRA). Sin embargo, el grado de acuerdo entre las distintas especialidades sobre el beneficio de estas técnicas en diferentes escenarios clínicos es controvertido. El objetivo del presente consenso fue elaborar una serie de recomendaciones de buena práctica clínica para la aplicación de soporte no invasivo en pacientes con IRA, avaladas por todas las sociedades científicas involucradas en el manejo del paciente adulto y pediátrico/neonatal con IRA. Para ello se contactó con las diferentes sociedades implicadas, quienes designaron a su vez a un grupo de 26 profesionales con suficiente experiencia en su aplicación. Se realizaron 3 reuniones presenciales para consensuar las recomendaciones (hasta un total de 71) fundamentadas en la revisión de la literatura y en la actualización de la evidencia disponible en relación con 3 categorías: indicaciones, monitorización yseguimiento del SRNI. Finalmente, se procedió a votación telemática de cada una de las recomendaciones, por parte de los expertos de cada sociedad científica implicada. Para la clasificación del grado de acuerdo se optó por un sistema analógico de clasificación fácil e intuitivo de usar, y que expresara con claridad si el procedimiento relacionado con el SRNI debía hacerse, podía hacerse o no debía hacerse. (AU)

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied. (AU)

Summary of recommendations and key points of the consensus of Spanish scientific societies (SEPAR, SEMICYUC, SEMES; SECIP, SENEO, SEDAR, SENP) on the use of non-invasive ventilation and high-flow oxygen therapy with nasal cannulas in adult, pediatric, and neonatal patients with severe acute respiratory failure.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.

Summary of recommendations and key points of the consensus of Spanish scientific societies (SEPAR, SEMICYUC, SEMES; SECIP, SENEO, SEDAR, SENP) on the use of non-invasive ventilation and high-flow oxygen therapy with nasal cannulas in adult, pediatric, and neonatal patients with severe acute respiratory failure. / Sumario de las recomendaciones y puntos clave del Consenso de las Sociedades Científicas Españolas (SEPAR, SEMICYUC, SEMES; SECIP, SENeo, SEDAR, SENP) para la utilización de la ventilación no invasiva y terapia de alto flujo con cánulas nasales en el paciente adulto, pediátrico y neonatal con insuficiencia respiratoria aguda grave.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.

Effectiveness of different treatments in obesity hypoventilation syndrome.

Obesity hypoventilation syndrome (OHS) is an undesirable consequence of obesity, defined as daytime hypoventilation, sleep disorder breathing and obesity; during the past few years the prevalence of extreme obesity has markedly increased worldwide consequently increasing the prevalence of OHS. Patients with OHS have a lower quality of life and a higher risk of unfavourable cardiometabolic consequences. Early diagnosis and effective treatment can lead to significant improvement in patient outcomes; therefore, such data has noticeably raised interest in the management and treatment of this sleep disorder. This paper will discuss the findings on the main current treatment modalities OHS will be discussed.

Finite element analysis of narrow dental implants.

Narrow-diameter implants (NDIs) traditionally have been associated to higher rates of failure in comparison with regular-diameter implants (RDIs) and wide-diameter implants (WDIs), since they generate a more unfavorable stress distribution in peri-implant bone. However, it is well known that the load sharing effect associated with prostheses supported by multiple implants (also called splinted prostheses) affords mechanical benefits. The present study involves finite element analysis (FEA) to determine whether the risks linked to NDIs could be mitigated by the mechanical advantages afforded by the splinting concept. For this purpose, a three-dimensional (3D) model of a real maxilla was reconstructed from computed tomography (CT) images, and different implants (NDIs, RDIs and WDIs) and prostheses were created using computer-aided design (CAD) tools. Biting forces were simulated on the prostheses corresponding to three different rehabilitation solutions: single-implant restoration, three-unit bridge and all-on-four treatment. Stress distribution around the implants was calculated, and overloading in bone was quantified within peri-implant volumes enclosed by cylinders with a diameter 0.1mm greater than that of each implant. The mechanical benefits of the splinting concept were confirmed: the peri-implant overloaded volume around NDIs splinted by means of the three-unit bridge was significantly reduced in comparison with the nonsplinted condition and, most importantly, proved even smaller than that around nonsplinted implants with a larger diameter (RDIs). However, splinted NDIs supporting the all-on-four prosthesis led to the highest risk of overloading found in the study, due to the increase in compressive stress generated around the tilted implant when loading the cantilevered molar.

Clinical Consensus Recommendations Regarding Non-Invasive Respiratory Support in the Adult Patient with Acute Respiratory Failure Secondary to SARS-CoV-2 infection. / Recomendaciones de consenso respecto al soporte respiratorio no invasivo en el paciente adulto con insuficiencia respiratoria aguda secundaria a infección por SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, that was first recognized in Wuhan, China, in December 2019. Currently, the World Health Organization (WHO) has defined the infection as a global pandemic and there is a health and social emergency for the management of this new infection. While most people with COVID-19 develop only mild or uncomplicated illness, approximately 14% develop severe disease that requires hospitalization and oxygen support, and 5% require admission to an intensive care unit. In severe cases, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS), sepsis and septic shock, and multiorgan failure. This consensus document has been prepared on evidence-informed guidelines developed by a multidisciplinary panel of health care providers from four Spanish scientific societies (Spanish Society of Intensive Care Medicine [SEMICYUC], Spanish Society of Pulmonologists [SEPAR], Spanish Society of Emergency [SEMES], Spanish Society of Anesthesiology, Reanimation, and Pain [SEDAR]) with experience in the clinical management of patients with COVID-19 and other viral infections, including SARS, as well as sepsis and ARDS. The document provides clinical recommendations for the noninvasive respiratory support (noninvasive ventilation, high flow oxygen therapy with nasal cannula) in any patient with suspected or confirmed presentation of COVID-19 with acute respiratory failure. This consensus guidance should serve as a foundation for optimized supportive care to ensure the best possible chance for survival and to allow for reliable comparison of investigational therapeutic interventions as part of randomized controlled trials.

Predicting Short- and Long-Term Outcomes in Adult Heart Transplantation: Clinical Utility of MELD-XI Score.

BACKGROUND: Model for End-Stage Liver Disease scoring system excluding international normalized ratio (MELD-XI) has been related with worse outcomes after heart transplantation (HT). However, according to standards in prognostic models research, before implementing a risk score for daily clinical decision-making, its performance and impact on clinical practice/outcomes should be evaluated. The aim of this study was to evaluate the ability of the MELD-XI score to predict outcomes in daily clinical practice. MATERIAL AND METHODS: We retrospectively reviewed 190 consecutive adults undergoing HT between 2005-2015. Patients were stratified into low (MELD-XI <12) and high (MELD-XI ≥12) risk cohorts. Mortality rates at 30 days and 1 year were compared between MELD-XI groups. MELD-XI ability to predict 1-year mortality was assessed by the area under the receiver operating curve (AUC) and compared to that of bilirubin, creatinine, and pulmonary vascular resistance (PVR). RESULTS: Mortality rates at 30 days and 1 year were similar between groups (8% vs 13%; P = .28 and 21% vs 29%; P = .21, respectively). MELD-XI ability to predict 1-year mortality was poor and similar to that of bilirubin, creatinine, and PVR (0.51 vs 0.47 vs 0.50 vs 0.50, respectively). CONCLUSIONS: MELD-XI score utility in HT clinical decision-making is scarce since its discrimination ability is poor and similar to other simple prognostic variables.

The prognosis of noncutaneous, nonlymphomatous malignancy after heart transplantation: data from the Spanish Post-Heart Transplant Tumour Registry.

INTRODUCTION: Malignancy is a major complication in the management of solid organ transplant patients. Skin cancers show a better prognosis than other neoplasms, but not all others are equal: Ideally, patient management must take into account the natural history of each type of cancer in relation to the transplanted organs. We sought to determine the prognosis of various groups of noncutaneous nonlymphomatous (NCNL) cancers after heart transplantation (HT). METHODS: We retrospectively analyzed the records of the Spanish Post-Heart-Transplant Tumour Registry, which collects data on posttransplant tumors in all patients who have undergone HT in Spain since 1984. Data were included in the study up to December 2008. We considered only the first NCNL post-HT tumors. RESULTS: Of 4359 patients, 375 developed an NCNL cancer. The most frequent were cancers of the lung (n=97; 25.9%); gastrointestinal tract (n=52; 13.9%); prostate gland (n=47; 12.5%; 14.0% of men), bladder (n=32; 8.5%), liver (n=14; 3.7%), and pharynx (n=14; 3.7%), as well as Kaposi's sarcoma (n=11; 2.9%). The corresponding Kaplan-Meier survival curves differed significantly (P<.0001; log-rank test), with respective survival rates of 47%, 72%, 91%, 73%, 36%, 64%, and 73% at 1 year versus 26%, 62%, 89%, 56%, 21%, 64%, and 73% at 2 years; and 15%, 51%, 77%, 42%, 21%, 64%, and 52% at 5 years post-diagnosis, respectively. CONCLUSION: Mortality among HT patients with post-HT NCNL solid organ cancers was highest for cancers of the liver or lung (79%-85% at 5 years), and lowest for prostate cancer (23%).

Effect of different pharmacologic agents to reverse severe pulmonary hypertension among end-stage heart failure patients.

OBJECTIVE: The goal of this study was to analyze the hemodynamic responses during vasoreactivity tests among candidates for heart transplantation who displayed severe pulmonary hypertension seeking to identify risk markers of nonresponse to the test. MATERIALS AND METHODS: In this observational retrospective study we evaluated demographic, clinical, echocardiographic, and hemodynamic variables. The target hemodynamic goal in the vasoreactivity test was to achieve a transpulmonary gradient (TPG) <12 mm Hg and/or pulmonary vascular resistances (PVR) <2.5 Wood Units (WU). RESULTS: We analyzed medical records from 79 patients. Inotropes (dopamine or dobutamine) were used to treat 33 patients, nonselective vasodilators (nitroglycerin or sodium nitroprusside) were used in 22 patients, and prostacyclin (PC) was used in 24 patients. The study observed a significant decrease in pulmonary pressures, PVR, and TPG, with increased cardiac output (CO) compared with baseline hemodynamics in all groups. No significant differences were observed between agents except for an increase in CO, which was greater in the PC group. Also, 49.4% of patients were considered responders to the vasoreactivity test without significant differences between groups. Risk markers for absence of a response to the vasoreactivity test were a CO <2.5 L/min (odds ratio [OR] = 2.1; confidence interval [CI] 95%, 1.1-3.9; P = .035) and a PVR >6 WU (OR = 3.7; CI 95%, 1.8-7.6; P < .001) in the baseline hemodynamic study. CONCLUSIONS: Inotropes, nonselective vasodilators, and prostacyclin produced effective vasodilator responses in the pulmonary vascular bed during the vasoreactivity test. The presence of a baseline high PVR or a low CO were predictors of nonresponse to the test.

Simultaneous determination of three antioxidants in foods and cosmetics by flow injection coupled to an ultra-short monolithic column.

The combination of an ultra-short C18 monolithic column (5 mm long) with flow injection analysis results in a versatile and efficient system that has been used for the determination of three antioxidants [propylgallate (PG), butylhydroxyanisole (BA), and butylhydroxytoluene (BT)]. Due to the wide variety of polarities of the analytes, two different carriers (carrier A: methanol-water 42% and carrier B: methanol-water 70%) were able to separate the analytes in only 85 s. The applicable concentration range, the detection, and the relative standard deviation (n=10) were: for PG, from 2.77 to 300 microg/mL, 0.84 microg/mL, 2.84%; for BA, between 1.51 and 300 microg/mL, 0.46 microg/mL, and 2.70%; and for BT, between 1.65 and 100 microg/mL, 0.55 microg/mL, and 2.22%, respectively. The method was applied and validated satisfactorily for the determination of PG, BA, and BT in food and cosmetic samples.

Intentional inhibition in memory and hallucinations: directed forgetting and updating.

Hallucinations have been recently associated with inhibitory deficits in memory. In this study, the authors investigated whether hallucinations were related to difficulties to inhibit irrelevant information from episodic memory (Experiment 1) and working memory (Experiment 2). In Experiment 1, a directed forgetting task was used. This task measures participants' ability to intentionally forget some recently learned material, when instructions indicate that it is no longer relevant. In Experiment 2, an updating task was used. This task requires participants to intentionally suppress irrelevant information from working memory. Results showed that patients with schizophrenia with hallucinations presented inhibitory deficits in the directed forgetting task and an increase in the number of intrusions in the updating task, compared to patients without hallucinations and healthy controls. No correlations were found between indices of inhibition and other general, negative or positive symptoms. These findings support the existence of an association between intentional inhibition in memory and hallucinations, and they suggest that problems to suppress memory representations can underlie hallucinations in schizophrenia.

[A preliminar mathematical model for patients with a previous negative prostate biopsy]. / Desarrollo de un Modelo Matemático preliminar para la detección de cancer de próstata en los pacientes con biopsias prostáticas de repetición.

INTRODUCTION AND OBJECTIVES: It is usual to identify patients with a negative prostate biopsy who are still at risk of prostate cancer. We try to analyse if the classical variables used in the prostate cancer screening are useful for those patients with a previous negative prostate biopsy, and if there is a possibility for making a nomogram witch would help us in the decision to repeat the biopsy. MATERIAL AND METHODS: We studied 179 patients with at least 1 initial negative biopsy. At each biopsy session we recorded: Patient age, serum prostate specific antigen (PSA), free PSA/total PSA, PSA slope, digital rectal examination, prostate volume, PSA density, cancer suspicion in previous transrectal ultrasounds findings, number of negative cores previously obtained, history of precarcinomatous lesions and time between biopsies. Through Logistic regression analysis we determined the association of each variable a positive biopsy. A nomogram was constructed using all variables and discrimination was calculated as the concordance index. RESULTS: Overall 46% of patients had cancer at the repeated biopsy session. In the univariate analysis: Age, digital rectal examination, prostate volume, PSA density, cancer suspicion in ultrasounds findings, and precarcinomatous lesions were associated with repeat positive biopsy for cancer (all p <0.05). In the multivariate study, age, digital rectal examination, prostate volume and history of precarcinomatous lesions were associated with repeat positive biopsy. A nomogram was constructed that had a concordance index of 0.80.

[Obstructive symptoms in young woman by left hydrosalpinx]. / Sintomatología obstructiva en mujer joven por hidrosalpinx izquierdo.

We describe the case of a 43 years old woman with obstructive and irritative symptoms after having an hysterectomy. Bladder outlet obstruction was observed in an urodinamyc study. She was later diagnosed with left hidrosalpinx. Salpingectomy was performed, as a result all symptoms have disap-

[Clinical features and histopathology of prostate cancer diagnosed from the third biopsy]. / Características clínicas e histopatológicas del cáncer de próstata diagnosticado a partir de la tercera biopsia.

OBJECTIVE: To study of histological and clinical features of prostate cancer diagnosed after three or more prostate biopsies in order to assess its clinical relevance and to discard the overdiagnosis of prostate cancer. MATERIAL AND METHODS: We reviewed the clinical records of 61 patients who underwent three or more prostate biopsies between January 2000 and December 2006. The analyzed variables were: age, PSA level, free/total PSA ratio, PSA density, digital rectal examination, prostate volume, sonographic findings and previous malignant lesion strongly associated to the presence of tumor on previous biopsy. We studied the pathology of the tumors diagnosed from the third biopsy, therapeutical approach and its evolution with a minimum follow-up of 3 months. RESULTS: Fifteen out of 61 patients with more than three biopsies had prostate cancer (24,59%) in the third biopsy, 5 out of 14 patients with 4 biopsies (35,71%) and 1 of the 2 cases (50%) who underwent a fifth biopsy. According to the results of biopsy, 6 patients met the criteria of clinically insignificant cancer (28,57%). Curative treatment was performed in all patients: brachytherapy in 5, external beam radiotherapy in 6 and radical prostatectomy in 10. Clinically significant tumors were found in all cases: 2 pT2b tumors and 7 pT2c tumors with negative surgical margins and with an excellent control of the cancer after a minimum follow up of 13 months, and one pT4 tumor with bladder neck infiltration. CONCLUSION: In our practice, overall detection rate of the third, fourth and fifth biopsy is 34,42% corresponding with tumors that could benefit from curative treatment.

Cognitive substrates in semantic memory of formal thought disorder in schizophrenia.

Formal thought disorder (FTD) has been associated with abnormalities in the semantic memory system. However, it is still unclear whether these abnormalities are related to the organization of the semantic system, or to the automatic spread of activation-inhibition in semantic networks. In this paper these alternative proposals are examined. Schizophrenic patients and healthy matched controls were given two semantic memory tasks. In the first task, participants were required to judge the similarity between pairs of natural concepts. These ratings are assumed to reflect the underlying knowledge organization. In the second task, participants were required to name pictures that were preceded by related or unrelated word primes. Interference is typically observed when pictures are preceded by semantically related primes, and it is explained as due to inhibitory processes from the word prime to the related picture target. The results showed that the semantic structures derived from the similarity ratings were similar for patients with and without FTD and for control participants. However, results from the picture-naming task indicated that both non-FTD and control participants showed the normal interference/inhibition effects from the related prime words, whereas the patients with FTD showed similar performance for pictures preceded by related words than for pictures preceded by unrelated words. These findings support the hypothesis that abnormalities in inhibitory processes in semantic memory underlie FTD.

Simultaneous determination of antioxidants, preservatives and sweetener additives in food and cosmetics by flow injection analysis coupled to a monolithic column.

Today it is common to find samples with various additives from several families. This is the case of sweeteners, preservatives and antioxidants. We have selected a set of additives broadly used in foods and cosmetics with an ample variety of polarities, namely: aspartame (AS), acesulfame (AK)/saccharin (SA), methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), propylgallate (PG) and butylhydroxyanisole (BA). The monolithic column used as separative system is a 5 mm commercial precolumn of silica C18 coupled to a flow injection manifold working with a peristaltic pump. The mixture was separated in only 400 s with resolution factors greater than 1.1 in all cases. To achieve the separation in the FIA system we used two carriers: first, a mixture of ACN/water buffered with 10 mM pH 6.0 phosphate buffer and second, a methanol:water mixture to improve the carrier strength and speed up the more apolar analytes at 3.5 mL min(-1). Detection is accomplished by means of a diode array spectrometer at the respective wavelength of each compound. The comparison of the analytical parameters obtained for this procedure with a standard HPLC method validates our new method, obtaining a method that is quick, with high repeatability and reproducibility and with good resolution between analytes. We have successfully applied the method to real food and cosmetics samples.

Resolution of an intense sweetener mixture by use of a flow injection sensor with on-line solid-phase extraction. Application to saccharin and aspartame in sweets and drinks.

An integrated solid-phase spectrophotometry-FIA method is proposed for simultaneous determination of the mixture of saccharin (1,2-benzisothiazol-3(2H)-one-1,1-dioxide; E-954) (SA) and aspartame (N-L-alpha-aspartyl-L-phenylalanine-1-methyl ester; E-951) (AS). The procedure is based on on-line preconcentration of AS on a C18 silica gel minicolumn and separation from SA, followed by measurement, at lambda = 210 nm, of the absorbance of SA which is transiently retained on the adsorbent Sephadex G-25 placed in the flow-through cell of a monochannel FIA setup using pH 3.0 orthophosphoric acid-dihydrogen phosphate buffer, 3.75x10(-3) mol L(-1), as carrier. Subsequent desorption of AS with methanol enables its determination at lambda = 205 nm. With a sampling frequency of 10 h(-1), the applicable concentration range, the detection limit, and the relative standard deviation were from 1.0 to 200.0 microg mL(-1), 0.30 microg mL(-1), and 1.0% (80 microg mL(-1), n = 10), respectively, for SA and from 10.0 to 200.0 microg mL(-1), 1.4 microg mL(-1), and 1.6% (100 microg mL(-1), n = 10) for AS. The method was used to determine the amounts of aspartame and saccharin in sweets and drinks. Recovery was always between 99 and 101%. The method enabled satisfactory determination of blends of SA and AS in low-calorie and dietary products and the results were compared with those from an HPLC reference method.