Myasthenia Gravis and Abdominal Aortic Aneurysm: A Rare Combination.

Abdominal aortic aneurysm in a patient with myasthenia gravis (MG) is extremely rare. We present a 64-year-old male with MG and an asymptomatic abdominal aortic aneurysm treated endovascularly. After extubation, he suffered a cardiac arrest due to an acute myocardial infarction. Cardiopulmonary resuscitation and a primary coronary angioplasty led to a satisfactory outcome. Special care is needed due to higher rates of postoperative complications in these patients.

Development and validation of a liquid chromatographic method with diode array detection for the determination of anthraquinones, flavonoids and other natural dyes in aged silk.

A HPLC method coupled with diode array detector was developed and validated for the quantitation of alizarin, apigenin, carminic acid, curcumin, ellagic acid, emodin, fisetin, kaempferide, kaempferol, kermesic acid, morin, purpurin, quercetin and sulfuretin which are components of several natural dyes. 1- Hydroxyanthraquinone was selected as internal standard. The compounds were separated under gradient elution on a RP-column (Altima C18, 250 mm x 3.0 mm i.d., 5 µm) with a mobile phase consisting of solvent A: H2O + 0.1% (v/v) trifluoroacetic acid and solvent B: acetonitrile + 0.1% (v/v) trifluoroacetic acid. The method was validated in terms of linearity, limits of detection and quantitation, accuracy, precision, ruggedness and robustness and applied to the analysis of silk dyed with buckthorn (Rhamnus trees), cochineal (Dactylopius coccus Costa), madder (Rubia tinctorum L.), turmeric (Curcuma longa L.) and young fustic (Cotinus coggygria Scop). Furthermore, dyed silk samples were subjected to artificially accelerated ageing conditions induced by UV radiation. The effect of the latter on the quantities of the aforementioned compounds was monitored, except for apigenin, kermesic acid and morin.

Single run analysis of glutathione and its disulfide in food samples by liquid chromatography coupled to on-line post-column derivatization.

Glutathione and its disulfide were determined in a single run using liquid chromatography with on-line post-column derivatization and fluorimetric detection (340 nm/425 nm). The analytes were separated using a reversed-phase column capable of operating at 100% aqueous mobile phase and detected following direct on-line reaction with o-phthalaldehyde (7.5 mmol L-1) in highly basic medium (0.37 mol L-1 NaOH). The instrumental and chemical variables were carefully investigated towards high sensitivity and throughput, while special attention was paid to validating potential matrix effects. Glutathione and its disulfide could be selectively determined with respective LODs of 0.10 and 0.30 µmol L-1 in the absence of matrix effect (<6%). The endogenous content of the analytes was accurately determined in various food samples with recoveries ranging between 80 and 120% in all cases. The proposed method is reliable and promising as a generic analytical tool for the convenient estimation of the redox status of glutathione in various food matrices.

Predictors of mortality of trauma patients admitted to the ICU: a retrospective observational study☆.

BACKGROUND AND OBJECTIVES: Worldwide, trauma is one of the leading causes of morbidity and mortality. The aim of the present study is to identify the predictors of mortality of trauma patients requiring Intensive Care Unit (ICU) admission. METHODS: This retrospective study was conducted in the ICU of our institution in Greece during a six-year period (2010-215). RESULTS: Among 326 patients, trauma was caused by road traffic accidents in .5%, followed by falls (21.1%) and violence (7.4%). Thirty-day mortality was 27.3%. Multivariate analysis showed that higher New Injury Severity Score (NISS), severe head/neck injury, acute kidney injury, septic shock and hemorrhagic shock were significantly associated with mortality while higher Revised Injury Severity Classification, version II (RISC II) and the administration of enteral nutrition were associated with survival. NISS showed the higher accuracy in predicting 30-day mortality followed by RISC II, while scores based only in physiological variables had lower predictive ability. CONCLUSIONS: Increased mortality was strongly associated with the severity of the injury upon admission. Traumatic brain injury, septic shock and acute kidney injury have also been found among the strongest predictors of mortality. NISS can be considered as a statistically superior score in predicting mortality of severely injured patients.

Frequency and Significance of Maneuvers to Dissect the Distal Internal Carotid Artery During Carotid Endarterectomy.

OBJECTIVES: To describe the frequency, factors associated with, and significance of surgical dissection maneuvers of the distal internal carotid artery (ICA) during carotid endarterectomy (CEA). METHODS: In this retrospective analysis of prospectively collected information in patients undergoing CEA, we recorded information on demographics, risk factors and comorbidities, dissection maneuvers of the distal ICA, other operative variables and neurological outcome measures. RESULTS: During the period July 2008 and February 2020 inclusive, 218 consecutive patients (180 males, median age 69.5 years) underwent 240 CEAs. In 117 (48.8%) of them, CEA was performed for a symptomatic stenosis. Dissection maneuvers of the distal ICA were required in 77 cases (32.1%), including division and ligation of the sternocleidomastoid vessels in 66 cases (27.5%), mobilization of the XII cranial nerve in 69 cases (28.7%, with concomitant transection of the superior root of the ansa cervicalis in 11 cases, 4.6%) and division of the posterior belly of the digastric muscle in 8 cases (3.3%). Styloid osteotomy was not required in any case. Smoking was the single predictive factor associated with the use of an adjunctive dissection maneuver (odds ratio 2.23, p = 0.009). The use of a patch was more common in smokers (16% vs 7.1% in non-smokers, odds ratio 2.48, p = 0.05). Perioperative stroke and/or death rate was 0%, not allowing testing for associations with maneuver performance. Two patients (0.8%) developed a transient ischemic attack and 4 patients (1.7%) a cranial nerve injury (CNI), including 2 patients with recurrent laryngeal nerve palsy, diagnosed on routine laryngoscopy during planning of a contralateral CEA. There was no association between CNI and dissection of the distal ICA using an operative adjunct (p = 0.60). CONCLUSIONS: Several surgical maneuvers are often required to accomplish dissection of the distal ICA beyond the point of atherosclerotic disease. When dictated by operative findings, such maneuvers are deemed safe.

A targeted approach for studying the effect of sugar bee feeding on the metabolic profile of Royal Jelly.

Royal Jelly (RJ) constitutes one of the most popular beehive products and for this reason the use of inexpensive sweeteners during its production remains an important quality issue. In the present study we report results of metabolic profiling of RJ samples obtained after the application of artificial bee-feeding using different feeding protocols. The hydrophilic content of RJ samples was assessed by applying (HILIC)UPLC-MS/MS. In total 96 crude RJ samples were analysed with the developed method. Multivariate statistical analysis revealed clear differentiation between the RJ samples obtained from control (non-fed) bees and samples obtained after feeding. In total 27 out of 57 detected molecules were statistically found to be significantly altered in the different comparisons. Among them some amino acids (e.g. tryptophan, lysine), amino acid derivatives (pyroglutamic acid), amines (cadaverine, TMAO, etc.), carbohydrates and vitamins were found as potential markers. The results of the study could be further used for the development of an LC-MS based analytical tool for RJ quality control assessment.

[Risk factors for mortality after subarachnoid hemorrhage: a retrospective observational study]. / Fatores de risco para mortalidade após hemorragia subaracnoidea: estudo observacional retrospectivo.

BACKGROUND AND OBJECTIVES: Subarachnoid haemorrhage is an important cause of morbidity and mortality. The aim of the study was to determine predictors of mortality among patients with subarachnoid hemorrhage hospitalized in an Intensive Care Unit. METHODS: This is a retrospective study of patients with subarachnoid hemorrhage admitted to the Intensive Care Unit of our institution during a 7 year period (2009-2015). Data were collected from the Intensive Care Unit computerized database and the patients' chart reviews. RESULTS: We included in the study 107 patients with subarachnoid haemorrhage. A ruptured aneurysm was the cause of subarachnoid haemorrhage in 76 (71%) patients. The overall mortality was 40% (43 patients), and was significantly associated with septic shock, midline shift on CT scan, inter-hospital transfer, aspiration pneumonia and hypernatraemia during the first 72 hours of Intensive Care Unit stay. Multivariate analysis of patients with subarachnoid hemorrhage following an aneurysm rupture revealed that mortality was significantly associated with septic shock and hypernatremia during the first 72 hours of Intensive Care Unit stay, while early treatment of aneurysm (clipping or endovascular coiling) within the first 72 hours was identified as a predictor of a good prognosis. CONCLUSIONS: Transferred patients with subarachnoid haemorrhage had lower survival rates. Septic shock and hypernatraemia were important complications among critically ill patients with subarachnoid haemorrhage and were associated increased mortality.

Risk factors for mortality after subarachnoid hemorrhage: a retrospective observational study / Fatores de risco para mortalidade após hemorragia subaracnoidea: estudo observacional retrospectivo

Abstract Background and objectives: Subarachnoid hemorrhage is an important cause of morbidity and mortality. The aim of the study was to determine predictors of mortality among patients with subarachnoid hemorrhage hospitalized in an Intensive Care Unit. Methods: This is a retrospective study of patients with subarachnoid hemorrhage admitted to the Intensive of our institution during a 7 year period (2009-2015). Data were collected from the Intensive Care Unit computerized database and the patients' chart reviews. Results: We included in the study 107 patients with subarachnoid hemorrhage. A ruptured aneurysm was the cause of subarachnoid hemorrhage in 76 (71%) patients. The overall mortality was 40% (43 patients), and was significantly associated with septic shock, midline shift on CT scan, inter-hospital transfer, aspiration pneumonia and hypernatraemia during the first 72 hours of Intensive Care Unit stay. Multivariate analysis of patients with subarachnoid hemorrhage following an aneurysm rupture revealed that mortality was significantly associated with septic shock and hypernatremia during the first 72 hours of Intensive Care Unit stay, while early treatment of aneurysm (clipping or endovascular coiling) within the first 72 hours was identified as a predictor of a good prognosis. Conclusions: Transferred patients with subarachnoid hemorrhage had lower survival rates. Septic shock and hypernatraemia were important complications among critically ill patients with subarachnoid hemorrhage and were associated increased mortality.

Resumo Justificativa e objetivos: A hemorragia subaracnoidea é uma causa importante de morbidade e mortalidade. O objetivo do estudo foi determinar os preditivos de mortalidade entre os pacientes com hemorragia subaracnoidea internados em uma Unidade de Terapia Intensiva. Métodos: Estudo retrospectivo de pacientes com hemorragia subaracnoidea internados na Unidade de Terapia Intensiva de nossa instituição de 2009 a 2015. Os dados foram coletados do banco de dados eletrônico da Unidade de Terapia Intensiva e de revisões dos prontuários dos pacientes. Resultados: Incluímos no estudo 107 pacientes com hemorragia subaracnoidea. A ruptura de aneurisma foi a causa da hemorragia subaracnoidea em 76 pacientes (71%). A mortalidade geral foi de 40% (43 pacientes) e esteve significativamente associada ao choque séptico, desvio da linha média na tomografia computadorizada, transferência inter-hospitalar, pneumonia por aspiração e hipernatremia durante as primeiras 72 horas de internação na Unidade de Terapia Intensiva. A análise multivariada dos pacientes com hemorragia subaracnoidea pós-ruptura de aneurisma revelou que a mortalidade esteve significativamente associada ao choque séptico e hipernatremia nas primeiras 72 horas de permanência na Unidade de Terapia Intensiva, enquanto o tratamento precoce do aneurisma (clipagem ou embolização endovascular) nas primeiras 72 horas foi identificado como preditivo de um bom prognóstico. Conclusões: Os pacientes com hemorragia subaracnoidea transferidos apresentaram taxas menores de sobrevivência. Choque séptico e hipernatremia foram complicações importantes entre os pacientes gravemente enfermos com hemorragia subaracnoidea e foram associados ao aumento da mortalidade.

Development and validation of an ultra high performance liquid chromatography-tandem mass spectrometry method for the determination of phthalate esters in Greek grape marc spirits.

An Ultra High Performance Liquid Chromatography - Tandem Mass Spectrometry method has been developed for the analysis of 12 phthalate esters in Greek grape marc spirits. The phthalates were separated on a U-VDSpher PUR 100 C18-E (100 mm x 2.0 mm, 1.8 µm) column by gradient elution. The analytes were ionized by positive electrospray ionization using the multiple reaction monitoring mode. The standard addition method was used for quantification and the Student's t-test was carried out to evaluate the matrix effect. The accuracy of the method was assessed by recovery experiments resulting in values from 81.6 to 109.6%. The detection limits ranged from 0.3 to 33.3 µg L-1.The proposed method was validated and successfully applied to the analysis of 45 samples collected from Greece and Cyprus. All phthalate esters proved to be present at least once in the analysed grape marc spirits samples, except only in cases of diphenyl phthalate and diisodecyl phthalate, while for the regulated phthalates only bis (2-ethylhexyl) phthalate was quantified above the legislative concentration limits.

Targeted profiling of hydrophilic constituents of royal jelly by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

In the present work a Hydrophilic Interaction Liquid Chromatography-tandem Mass Spectrometry (HILIC-MS/MS) method was developed for the efficient separation and quantification of a large number of small polar bioactive molecules in Royal Jelly. The method was validated and provided satisfactory detection sensitivity for 88 components. Quantification was proven to be precise for 64 components exhibiting good linearity, recoveries R% >90% for the majority of analytes and intra- and inter-day precision from 0.14 to 20% RSD. Analysis of 125 fresh royal jelly samples of Greek origin provided useful information on royal jelly's hydrophilic bioactive components revealing lysine, ribose, proline, melezitose and glutamic acid to be in high abundance. In addition the occurrence of 18 hydrophilic nutrients which have not been reported previously as royal jelly constituents is shown.

Wine and grape marc spirits metabolomics.

INTRODUCTION: Mass spectrometry (MS)-based and nuclear magnetic resonance (NMR) spectroscopic analyses play a key role in the field of metabolomics due to their important advantages. The use of metabolomics in wine and grape marc spirits allows a more holistic perspective in monitoring and gaining information on the making processes and thus it can assist on the improvement of their quality. OBJECTIVES: This review surveys the latest metabolomics approaches for wine and grape marc spirits with a focus on the description of MS-based and NMR spectroscopic analytical techniques. METHODS: We reviewed the literature to identify metabolomic studies of wine and grape marc spirits that were published until the end of 2017, with the key term combinations of 'metabolomics', 'wine' and 'grape marc spirits'. Through the reference lists from these studies, additional articles were identified. RESULTS: The results of this review showed that the application of different metabolomics approaches has significantly increased the knowledge of wine metabolome and grape marc spirits; however there is not yet a single analytical platform that can completely separate, detect and identify all metabolites in one analysis. CONCLUSIONS: The authentication and quality control of wines and grape marc spirits has to be taken with caution, since the product's chemical composition could be affected by many factors. Despite intrinsic limitations, NMR spectroscopy and MS based strategies remain the key analytical methods in metabolomics studies. Authenticity, traceability and health issues related to their consumption are the major research initiatives in wine and grape marc spirits metabolomics analysis.

Risk factors and predictors of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii mortality in critically ill bacteraemic patients over a 6-year period (2010-15): antibiotics do matter.

Purpose. Acinetobacter baumannii and Pseudomonas aeruginosa provoke serious infections, especially in intensive care unit (ICU) patients.Methodology. The risk factors and predictors of mortality for P. aeruginosa (n=84; 46 carbapenem-resistant) and A. baumannii (n=129; all carbapenem-resistant) bloodstream infections (BSIs) in an ICU were evaluated. Antibiotic susceptibility testing was performed using the agar disk diffusion method according to EUCAST guidelines. The minimum inhibitory concentration was determined by a gradient method (Etest). Multilocus sequence typing (MLST) was performed for P. aeruginosa during the carbapenem-resistant outbreak in 2014. Epidemiological data were collected from the patients' chart reviews.Results/Key findings. Hospitalization during the summer months, prior KPC-producing Klebsiella pneumoniae (KPC-Kp) BSI, and the administration of tigecycline, aminoglycosides and cortisone were independently associated with P. aeruginosa BSIs. MLST revealed the dissemination of clone ST227, including carbapenem-resistant P. aeruginosa strains. Hospitalization during the summer months, prior KPC-Kp BSI, and the administration of antibiotics, carbapenem and cortisone were independently associated with A. baumannii BSIs. The 30-day mortality rate for P. aeruginosa and A. baumannii BSI was 45.2 and 39.5 %, respectively. Sequential organ failure assessment (SOFA) score at onset, septic shock, age, and prior KPC-Kp BSI were significantly associated with P. aeruginosa BSI mortality. The administration of at least one active antibiotic was identified as a predictor of a good prognosis. Septic shock and simplified acute physiology score (SAPS) II at onset were independently associated with A. baumannii BSI mortality. The administration of at least one active antibiotic and colistin-vancomycin co-administration were identified as predictors of a good prognosis.Conclusion. KPC-Kp infection predisposes ICU patients to BSI by either A. baumannii or P. aeruginosa. The administration of at least one active antibiotic leads to better survival rates.

Early KPC-Producing Klebsiella pneumoniae Bacteremia among Intensive Care Unit Patients Non-Colonized upon Admission.

Among 140 patients colonized by KPC-producing Klebsiella pneumoniae (KPC-Kp) between fourth and seventh day of Intensive Care Unit stay, 24 developed bacteraemia immediately after colonization. Colistin-resistance of the colonizing isolate was the factor significantly associated with early KPC-Kp bacteraemia (P < 0.001; OR 6.6, 95% CI 2.4-18.4), a worrisome finding since infections by colistin-resistant isolates is associated with increased mortality due to limited remaining therapeutic options.

The Role of Obesity in Sepsis Outcome among Critically Ill Patients: A Retrospective Cohort Analysis.

Background. The objective of this study was to assess the correlation between sepsis, obesity, and mortality of patients admitted to an Intensive Care Unit (ICU). Subjects and Methods. Data of all patients admitted to the ICU of a tertiary hospital during a 28-month period were retrospectively analyzed and included in the study. Results. Of 834 patients included, 163 (19.5%) were obese, while 25 (3.0%) were morbidly obese. Number of comorbidities (P < 0.001), bloodstream infection (P 0.033), and carbapenemase-producing Klebsiella pneumoniae colonization during ICU stay (P 0.005) were significantly associated with obesity, while nonobese patients suffered more frequently from spontaneous intracranial hemorrhage (P 0.038). Total ICU mortality was 22.5%. Increased mortality among obese ICU patients was observed. Sepsis was the main condition of admission for which obese patients had statistically lower survival than normal weight subjects (76.3% versus 43.7%; P 0.001). Mortality of septic patients upon admission was independently associated with SOFA score upon ICU admission (P 0.003), obesity (P 0.014), pneumonia (P 0.038), and development of septic shock (P 0.015). Conclusions. Our study revealed that sepsis upon ICU admission is adversely influenced by obesity but further studies are needed in order to assess the role of obesity in sepsis outcome.

Preoperative High Dose of Methylprednisolone Improves Early Postoperative Pulmonary Function, in Super-Obese Patients Undergoing Open Surgery; a Prospective, Comparative Study.

BACKGROUND: Surgery stimulates an intense systemic inflammatory response which might increase postoperative morbidity. Corticosteroids may reduce this inflammatory reaction. The purpose of this study was to investigate any possible effect on postoperative morbidity and recovery after administrating methylprednisolone in super-obese patients undergoing open surgery. METHODS: Sixty super-obese patients with BMI ≥50 kg/m2 (mean 57.48 ± 7.33), mean age of 39 ± 9 years, who underwent an open bariatric procedure, were enrolled. Thirty patients (group A) were allocated to a preoperative single dose of 30 mg/kg (ideal body weight) methylprednisolone versus placebo (group B, 30 patients). Endpoints included assessment of IL-6 and CRP; evaluation of postoperative pulmonary function, pain management, nausea, and vomiting; and documentation of postoperative complications. RESULTS: Significant improvement in spirometry parameters and arterial blood gas analysis, in the first and third postoperative days, was observed in the methylprednisolone group. IL-6 and CRP levels were significantly lower in that group. Administration of methylprednisolone was associated with less postoperative pain, nausea, and vomiting, with no statistical difference in septic complications. CONCLUSIONS: Preoperative administration of a single high dose of methylprednisolone in super-obese patients undergoing open surgery inhibits the inflammatory signaling cascade, lessens the systemic inflammatory response, and results in fewer pulmonary complications and better patient recovery.

Determination of Tyrian purple by high performance liquid chromatography with diode array detection.

Indigotin, indirubin, 6-bromoindigotin, 6'-bromoindirubin, 6-bromoindirubin, 6,6'-dibromoindigotin and 6,6'-dibromoindirubin, the colouring components of Tyrian purple, are quantified by an efficient HPLC method coupled to a diode array detector. The compounds were separated using gradient elution, on a RP-column (Alltima C18, 250mm×3.0mm i.d., 5µm), thermostated at 35°C, with a mobile phase consisting of solvents (Α) H2O+0.1% (v/v) trifluoroacetic acid and (Β) acetonitrile+0.1% (v/v) trifluoroacetic acid, at a flow rate of 0.5mLmin(-1). The method was validated in terms of linearity, detection and quantification limits, precision, accuracy, ruggedness and robustness, the latter with respect to small changes in column temperature and in flow-rate, pH- and solvent composition of the mobile phase. Under optimal conditions, the developed analytical scheme offers limits of detection in the range 0.02-0.05µgmL(-1) and satisfactory linearity up to 2.5µgmL(-1) for all analytes. Four samples produced from the hypobranchial glands of Hexaplex (Murex) trunculus molluscs, collected in the coastlines of Tunisia and Croatia, were treated with hot DMSO and analysed by the established HPLC method, using the standards addition approach. To evaluate the matrix effect, a comparison of the slopes of the standards in solvent regression curves with those of the standard addition method's calibration curves, using the Student's t-test was carried out. The accuracy was evaluated by recovery experiments. Amounts of indigotin, indirubin, and their mono- and dibrominated derivatives ranging between 0.01 to 12.2µgmg(-1) were found in the DMSO extracts of the four molluscan samples.

Automated derivatization and fluorimetric determination of biogenic amines in milk by zone fluidics coupled to liquid chromatography.

A novel zone-fluidics/high pressure liquid chromatographic (ZF-HPLC) method is described for the simultaneous determination of six biogenic monoamines, in the presence of hexylamine as internal standard. Automated on-line derivatization of the analytes with naphthalene-2,3-dicarboxaldehyde/cyanide ions was performed using the ZF concept and the derivatives were injected on the HPLC column for separation/detection. The influence of the ZF operation conditions on the derivatization reaction was investigated. The isoindoles formed were separated on a Kromasil C18 column (250 mm × 4 mm i.d., 5 µm), using an isocratic mobile phase of methanol/water (80:20, v/v) at a flow rate of 1.0 mL min(-1). Monitoring and quantification was carried out by fluorescence detection at 424/494 nm. The limits of detection were at the pg level with a sample volume of 20 µL. The whole procedure was evaluated and fully validated for the determination of biogenic amines in milk samples.

Does epidural morphine loading in addition to thoracic epidural analgesia benefit the postoperative management of morbidly obese patients undergoing open bariatric surgery? A pilot study.

BACKGROUND: Insufficient data exist regarding postoperative thoracic epidural analgesia for morbidly obese patients undergoing open bariatric surgery. This study evaluated the effectiveness of morphine loading in a postoperative thoracic epidural analgesic regimen of patient-controlled epidural analgesia (PCEA) with levobupivacaine combined with continuously administered epidural morphine in this patient group. METHODS: In this prospective randomized controlled trial, 48 superobese patients (body mass index of ≥ 50 kg/m(2)) undergoing open bariatric surgery were randomly allocated to three groups of 16 patients each. Postoperatively, all groups received a continuous epidural morphine infusion of 0.2 mg/h with 0.1 % levobupivacaine via PCEA. Group A did not receive intraoperative epidural morphine loading, while groups B and C received an intraoperative 1- and 2-mg morphine bolus, respectively. Levobupivacaine consumption via PCEA (primary outcome), pain scores at rest and on cough, the time to return of bowel function and ambulation, and arterial blood gas levels (secondary outcomes) were recorded. RESULTS: The increase in perioperative morphine administration (groups B and C) led to a significantly prolonged return to normal bowel function and delayed ambulation (P<0.05 to 0.01, respectively), without an improvement in postoperative analgesia or a reduction in local anesthetic consumption. Although the prevalence of obstructive sleep apnea (OSA) was high in all groups, no respiratory depression was observed. CONCLUSIONS: Thoracic PCEA with 0.1 % levobupivacaine combined with continuous epidural morphine administration of 0.2 mg/h without morphine loading is an effective postoperative analgesic regimen that provides adequate pain control, early ambulation, and early return of bowel function in superobese patients, particularly those with OSA.

Determination of glutathione in baker's yeast by capillary electrophoresis using methyl propiolate as derivatizing reagent.

In this study we demonstrate - for the first time - the suitability of methyl propiolate - an alkylester of propiolic acid - as a thiol derivatizing reagent for capillary electrophoresis. Glutathione (as analyte in yeast samples) and N-acetylcysteine (as internal standard) were selected as model compounds. Several parameters affecting the separation efficiency (buffer pH, concentration, and separation voltage) and the derivatization yield (pH, reaction time and reagent concentration) were thoroughly investigated. Validation was carried out towards the determination of glutathione in commercially available yeast samples. The LOD was 1.5µmolL(-1) and the linearity was obeyed in the range of 25-200µmolL(-1). The accuracy in terms of recoveries ranged between 95.9% and 113.6%. The approach proved to be free from matrix effects, while the results were confirmed by a corroborative method based on liquid chromatography coupled to post-column derivatization.