RESUMEN

BACKGROUND: Annually, almost 2 billion peripheral intravenous cannulas (PIVCs) are placed worldwide. In response to concerns of infectious complications, chlorhexidine is increasingly utilised for maintenance decontamination of PIVC injection ports. Concomitantly, the allergenic potential of chlorhexidine exposures has been highlighted by several case reports, implicating it as a trigger when used for this seemingly innocuous process. Given how widespread this application is, elucidating potential chlorhexidine exposure is needed to gauge its risks and benefits. OBJECTIVE: To examine and quantify if chlorhexidine is entrained when used for PIVC injection port cleaning. METHODS: Twenty benchtop PIVC set-ups were cleaned with 2% chlorhexidine and 70% alcohol wipes, following three different pragmatic protocols. Each set-up was injected with 10 ml ultrapure water, and samples tested by liquid chromatography-electrospray tandem mass spectrometry for entrained chlorhexidine. RESULTS: Chlorhexidine was detected in every sample. Mean concentrations and standard deviations from each protocol were 41.47 ppb (4.08), 54.76 ppb (17.46), and 65.84 ppb (7.01). One-way ANOVA indicated a statistical difference between at least two groups (df = 2, F = 24.11, p < .00001), with Tukey's testing verifying significantly different mean concentrations between all groups (p < .01). CONCLUSIONS: Using 2% chlorhexidine and 70% alcohol swabs to decontaminate PIVC injection ports resulted in consistent entrainment of chlorhexidine, with varying amounts correlated to how it was applied. These results validate case reports attributing anaphylactic/allergic reactions to suspected intravenous chlorhexidine entrainment and should factor into future risk-benefit assessments for its use in PIVC maintenance antisepsis policies and protocols.

Asunto(s)

RESUMEN

Advances in metabolomics analysis and data treatment increase the knowledge of complex biological systems. One of the most used methodologies is gas chromatography-mass spectrometry (GC-MS) due to its robustness, high separation efficiency, and reliable peak identification through curated databases. However, methodologies are not standardized, and the derivatization steps in GC-MS can introduce experimental errors and take considerable time, exposing the samples to degradation. Here, we propose the injection-port derivatization (IPD) methodology to increase the throughput in plasma metabolomics analysis by GC-MS. The IPD method was evaluated and optimized for different families of metabolites (organic acids, amino acids, fatty acids, sugars, sugar phosphates, etc.) in terms of residence time, injection-port temperature, and sample/derivatization reagent ratio. Finally, the method's usefulness was validated in a study consisting of a cohort of obese patients with or without nonalcoholic steatohepatitis. Our results show a fast, reproducible, precise, and reliable method for the analysis of biological samples by GC-MS. Raw data are publicly available at MetaboLights with Study Identifier MTBLS5151.

Asunto(s)

RESUMEN

BACKGROUND: Most peripheral venous catheters (PVCs) used in Scandinavia are fitted with an injection port, creating an open PVC system. This port is difficult to disinfect, which may lead to the introduction of micro-organisms upon use. AIM: To investigate the prevalence of microbiological colonization of the injection port and internal lumen of ported PVCs with a minimum dwell time of 48 h at sample collection. METHODS: Adult patients admitted to different medical and surgical departments and the intensive care unit were invited to participate in this prospective observational study. With the PVC in situ, the injection port and internal lumen were swabbed and cultured separately. Demographic and clinical data were collected to compare patients with colonized and non-colonized PVCs. FINDINGS: In total, 300 PVCs from 300 patients were analysed. Of these, 33 patients (11.0%) had at least one positive culture. The colonization locations were as follows: port only, 26 (8.7%); internal lumen only, 5 (1.7%); and port and internal lumen, 2 (0.7%). The colonization rate was significantly higher in the injection port than in the internal lumen (P<0.0001). A ported PVC inserted in the hand incurred a significant risk of colonization (P=0.03). The odds ratio for colonization among patients in the infectious diseases department was 0.1 (95% confidence interval 0.1-1; P<0.06) compared with patients in the medical department. CONCLUSION: This study showed that 11% of ported PVCs were colonized by micro-organisms, with the vast majority (8.7%) of colonization occurring in the injection port. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; ID NCT03351725.

RESUMEN

Ephedra herb extracts are being extensively investigated in terms of their antioxidative, antimicrobial and antiproliferative properties, with phenolic components being the general carriers of these bioactivities. Here we describe a comprehensive set of analytical methods employed to determine and characterize both the antioxidative activity and the qualitative profile of phenolic acids and flavonoids present in several Ephedra species of different geographical origin. Spectrophotometric methods were used to determine the total phenolic content, total flavonoid content and antioxidative activity. Multi-development HPTLC enabled chemical fingerprinting which can be used for species differentiation. Individual spots of the thin-layer chromatogram were subjected to GC-MS with injection port derivatization for identification, which was based on both the detected mass spectra and recorded retention indices. The results were compared and complemented with GC-MS using offline derivatization.

Asunto(s)

RESUMEN

A simple, rapid, cost-effective and environment friendly analytical method based on dispersive liquid-liquid microextraction (DLLME) coupled to injection port silylation (IPS)-gas chromatography-mass spectrometry is described for the determination of morphine in illicit opium samples. Raw opium was dispersed in ultrapure water and 5 mL of aqueous sample was subjected to DLLME by rapidly injecting a mixture of chloroform and acetone (extraction and disperser solvent, respectively) followed by ultrasonication for 1 min and subsequent centrifugation for 3 min at 5000 rpm. The sedimented phase thus obtained was reconstituted in acetonitrile and 1 µL along with 1 µL of N,O-Bis(trimethylsilyl)acetamide (BSA) was injected manually into GC-MS injection port at a temperature of 250°C. The derivatization reaction was completed instantaneously inside the heated GC-MS injection port without any side product. Various parameters associated with IPS and DLLME have been thoroughly optimized. Under the optimized conditions, the method has been found linear in the range of 5-50 µg/mL with a correlation coefficient (R 2) of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) for morphine-diTMS were found to be 1.6 and 4.8 µg/mL. The method has been successfully applied for the quantitative analysis of morphine in illicit opium samples. In conclusion, the proposed method has completely eliminated the time consuming and laborious steps of LLE and in-vial silylation and can be routinely used for analysis of opium and other polar analytes in forensic science laboratories.

RESUMEN

Intracellular cobalamin metabolism (ICM) defects can be present as autosomal recessive or X-linked disorders. Parenteral hydroxocobalamin (P-OHCbl) is the mainstay of therapy, but the optimal dose has not been determined. Despite early treatment, long-term complications may develop. We have analyzed the biochemical and clinical responses in five patients with early onset of different types of ICM defects (cblC: patients 1-3; cblA: patient 4; cblX: patient 5) following daily P-OHCbl dose intensification (DI). In patient 4, P-OHCbl was started at age 10 years and in patient 5 at age 5 years. OHCbl was formulated at either, 5, 25, or 50 mg/mL. P-OHCbl was intravenously or subcutaneously (SQ) delivered, subsequently by placement of a SQ injection port except in patient 4. In all patients, homocysteine and methylmalonic acid levels, demonstrated an excellent response to various P-OHCbl doses. After age 36 months, patients 1-3 had a close to normal neurological examination with lower range developmental quotient. In patient 3, moderate visual impairment was present. Patient 4, at age 10 years, had normal renal, visual and cognitive function. In cblX patient 5, epilepsy was better controlled. In conclusion, P-OHCbl-DI caused an excellent control of metabolites in all patients. In the three cblC patients, comparison with patients, usually harboring identical genotype and similar metabolic profile, was suggestive of a positive effect, in favor of clinical efficacy. With P-OHCbl-DI, CblA patient has been placed into a lower risk to develop renal and optic impairment. In cblX patient, lower P-OHCbl doses were administrated to improve tolerability.

RESUMEN

BACKGROUND: The use of intravenous (IV) cannulas is an integral part of patient care in hospitals. These intravenous cannulas are a potential route for microorganisms to enter the blood stream resulting in a variety of local or systemic infections. Studies showing the actual prevalence of colonization of peripheral IV cannulas and its role in BSI are lacking. Hence, this study was aimed to estimate the prevalence of colonization of the injection ports of peripheral IV cannulas. METHODS: This cross sectional study was conducted on patients admitted in ICU and wards in an 800 bedded tertiary care hospital. Swabs were taken from lumens of peripheral IV cannulas and cultured. Patient demographic data and practices followed for maintenance of IV line were noted. RESULTS: A total of 196 injection port samples were taken, out of which 11 tested positive for microbial growth (5.61%). Staphylococcus aureus was the predominant organism contributing 64% of the microbial growth. A significant association was seen between presence of local signs, old age and positive cultures. Flushing IV cannula every 6 h was associated with negative cultures. CONCLUSION: Peripheral IV cannulation has significant potential for microbial contamination and is largely ignored. Most of the risk factors associated with growth of microorganisms in the injection ports of peripheral intravenous cannulas (which has a potential to cause catheter-related blood stream infections) can be prevented by improving protocols for management. To prevent infection from occurring, practitioners should be educated and trained about the care and management of IV.

Asunto(s)

RESUMEN

The paper presents a new procedure for the determination of organic acids in a complex aqueous matrix using ultrasound-assisted dispersive liquid-liquid microextraction followed by injection port derivatization and GC-MS analysis. A deep eutectic solvent (choline chloride: 4-methylphenol in a 1:2 mol ratio) was used both as an extracting solvent and as a derivatizing agent to yield ion pairs which were next converted to methyl esters of organic acids in a hot GC injection port. The procedure was optimized in terms of selection of a deep eutectic solvent, disperser solvent, and the ratio of their volumes, pH, salting out effect, extraction time, injection port temperature and time of opening the split valve. The developed procedure is characterized by low LOD (1.7-8.3 µg/L) and LOQ (5.1-25 µg/L) values, good repeatability (RSD ranging from 4.0 to 6.7%), good recoveries for most of the studied analyte (81,5-106%) and a wide linear range. The procedure was used for the determination of carboxylic acids in real effluents from the production of petroleum bitumens. A total of ten analytes at concentrations ranging from 0.33 to 43.3 µg/mL were identified and determined in the effluents before and after chemical treatment. The study revealed that in effluents treated by hydrodynamic cavitation an increase in concentration of benzoic acid and related compounds was observed.

Asunto(s)

RESUMEN

The paper presents a new method for the determination of 15 carboxylic acids in samples of postoxidative effluents from the production of petroleum bitumens using ion-pair dispersive liquid-liquid microextraction and gas chromatography coupled to mass spectrometry with injection port derivatization. Several parameters related to the extraction and derivatization efficiency were optimized. Under optimized experimental conditions, the obtained limit of detection and quantification ranged from 0.0069 to 1.12µg/mL and 0.014 to 2.24µg/mL, respectively. The precision (RSD ranged 1.29-6.42%) and recovery (69.43-125.79%) were satisfactory. Nine carboxylic acids at concentrations ranging from 0.10µg/mL to 15.06µg/mL were determined in the raw wastewater and in samples of effluents treated by various oxidation methods. The studies revealed a substantial increase of concentration of benzoic acids, in samples of wastewater after treatment, which confirms the need of carboxylic acids monitoring during industrial effluent treatment processes.

Asunto(s)

RESUMEN

A method consisting of dispersive liquid-liquid microextraction (DLLME) followed by injection-port derivatization and gas chromatography-mass spectrometry (GC-MS) for the analysis of free lipophilic compounds in fruit juices is described. The method allows the analysis of several classes of lipophilic compounds, such as fatty acids, fatty alcohols, phytosterols and triterpenes. The chromatographic separation of the compounds was achieved in a chromatographic run of 25.5min. The best conditions for the dispersive liquid-liquid microextraction were 100µL of CHCl3 in 1mL of acetone. For the injection-port derivatization, the best conditions were at 280°C, 1min purge-off, and a 1:1 sample:derivatization reagent ratio (v/v) using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA):pyridine (1:1) as reagent. Quality parameters were assessed for the target compounds, giving a limits of detection (LODs) ranging from 1.1 to 5.7ng/mL and limits of quantification (LOQs) from 3.4 to 18.7ng/mL for linoleic and stearic acid, respectively. Repeatability (%RSD, n=5) was below 11.51% in all cases. In addition, the method linearity presented an r2 ≥0.990 for all ranges applied. Finally, the method was used to test the lipophilic fraction of various samples of commercial fruit juice.

Asunto(s)

RESUMEN

A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6µg/kg and LOQ of 2 and 5µg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000µg/kg and between 5 and 192µg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples.

Asunto(s)

RESUMEN

Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used.

Asunto(s)

RESUMEN

A method of derivatization at injection port following three phase hollow fiber microextraction with tetramethylammonium hydroxide (TMAH) as a dual-function reagent, for the simultaneous determination of salicylic acid, p-hydroxybenzoic acid, cinnamic acid, vanillic acid, p-coumaric acid and ferulic acid in beers by gas chromatography was developed. Phenolic acids were extracted from aqueous samples to a thin layer of organic solvent ( hexyl acetate) phase impregnated into the pores of the hollow fiber wall, and then back extracted to an acceptor solution (TMAH) located inside the lumen of the hollow fiber. Upon injection, the phenolic acids were derivatized to their methyl esters in the GC injection port. Several parameters related to the derivatization and extraction efficiency were optimized. The optimized conditions were as follows: hexyl acetate was used as the extraction solvent, an aqueous solution of TMAH (5% W/ V) was used as the derivatization reagent and acceptor phase, the pH value of donor phase was 2. 0, the concentrations of NaCl was 25% W/ V, the stirring rate was 500 r/ min, the extraction time was 40 min. Under the optimal conditions, the linear range of phenolic acids was 0. 50 -15. 00 mg / L, the limits of detection were 0. 05 -0. 18 mg / L. The proposed method was applied to the determination of the phenolic acids in beers. Vanillic acid, p-coumaric acid and ferulic acid were found in the beer samples, others were not detected. The spiked average recoveries were 90. 1% -106. 8% and RSD% was less than 5. 9% (n =3). The method is suitable for the determination of phenolic acids in beers.

RESUMEN

An efficient method based on ultrasound-assisted emulsification microextraction followed by injection-port derivatization GC analysis was developed to determine 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA) in natural water samples. In this procedure, 12.5 µL of 1-undecanol was injected slowly into a 12 mL home-designed centrifuge glass vial containing an aqueous sample of the analytes located inside an ultrasonic water bath. The resulting emulsion was centrifuged, and 1 µL of the separated organic solvent together with 1 µL of the derivatization reagent were injected into a GC equipped with a flame ionization detector. Several factors that influence the derivatization and extraction were optimized. Under the optimal conditions, the LODs were 0.33 and 1.7 µg/L for MCPA and 2,4-D, respectively. Preconcentration factors of 670 and 836 were obtained for MCPA and 2,4-D, respectively. The precision of the proposed method was evaluated in terms of repeatability, which was <5.7% (n = 5). The applicability of the proposed method was evaluated by extraction and determination of chlorophenoxyacetic acids from some natural waters, which indicated that the matrices of natural waters have no significant effect on the extraction and derivatization efficiency of this method.

Asunto(s)