Determination of cypermethrin in palm oil matrices

In this study, a new method was developed for the determination of cypermethrin residue in both crude palm oil (CPO) and crude palm kernel oil (CPKO) using GC with electron capture detector. In this method, the oil was extracted with acetonitrile. Aliquots were cleaned-up using combined solid phase extraction (SPE), and a primary-secondary amine in combination with graphitized carbon black. The SPE cartridges were first conditioned and then eluted with acetonitrile. Cypermethrin recoveries from the fortified CPO samples were 87-98 with relative standard deviation (RSD) values of 4-8, while those for the fortified CPKO samples were 83-100 with RSD values of 3-10. Since good recoveries were obtained with RSD values below 10 in most cases, the proposed methodology will be useful for the analyses of palm oil samples. The method was successfully applied to the analysis of cypermethrin in real palm oil samples from various parts of Malaysia. No cypermethrin residue was found among 30 samples analyzed

Study of removal of phenol species by adsorption on non-ionic silicon surfactant after cloud point extraction methodology

In the present study, CPE was carried out to extract phenol species from aqueous solution using the non-ionic silicone surfactant of DC193C. The non-ionic silicone surfactant of DC193C was chosen because of it is well known as an environmentally friendly solvent. The adsorption mechanism between the non-ionic silicone surfactant of DC193C and phenol species was studied. Our results indicate that, the adsorption of the phenol species from aqueous solution on the DC193C surfactant was in proportion to their hydrophobicities, according to the following order; 4-NP < 2,4-DCP < 2,4,6-TCP. The data of the equilibrium concentration and amount of adsorption in the CPE system for the three phenols species follow the Langmuir-type isotherm. On some assumptions, a developed Langmuir isotherm was used to calculate the feed surfactant concentration required for the removal of the three phenol species up to the extraction efficiency of 90%. The developed correlations may be useful to design a cloud point extractor of a desired efficiency. Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also calculated. These parameters indicated that the adsorption of the three phenol species solubilized into the non-ionic DC193C surfactant is feasible, spontaneous, and endothermic in the temperature ranging from 298 to 353 K

Comparative study of different clean-up techniques for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with electron capture detection

Solid phase extraction (SPE) and dispersive solid-phase extraction (d-SPE) were compared and evaluated for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C 18, silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81 and 114 at five fortification levels with the relative standard deviation of less than 7 in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05 μg/g. The proposed method was applied successfully for the residue determination of both λ-cyhalothrin and cypermethrin in crude palm oil samples obtained from local mills throughout Malaysia

Cloud point extraction of 2,4−dichlorophenol from aqueous samples employing β−cyclodextrin

In this study, β−cyclodextrin (β−CD) was used to enhance the extraction of 2,4−dichlorophenol (2,4−DCP) from the aqueous sample in cloud point extraction (CPE) using spectrophotometric method. Several parameters have been investigated with and without the presence of β−CD modifier, such as pH, equilibration temperature, analyte concentration, and water content in the CPE and CPE−βCD systems, respectively. Equilibrium data are described by the Langmuir isotherm in both CPE systems with and without β−CD modifier. The thermodynamic parameters (positive values of ΔH° and ΔS°, negative values of ΔG°) indicate that the solubilization of 2,4−DCP in a polyethylene glycol silicone surfactant (DC193C) is endothermic, entropy gained, and spontaneous in both systems. In the CPE−βCD system, the results show that the β−CD modifier is capable of enhancing the extraction of 2,4−DCP pollutant from aqueous samples

A rapid and cost effective ultrasonic solvent extraction method for determination of lambda-cyhalothrin and cypermethrin residues in soil

An effective, simple, and cost effective ultrasonic solvent extraction procedure was developed for the determination of lambda-cyhalothrin and cypermethrin residues in soil by gas chromatography with electron capture detector (GC-ECD). Several extraction parameters were optimised with regard to the solvent type, solvent volume and duration of sonication. Under the optimum conditions, recovery studies were performed at five fortification levels (0.01, 0.02, 0.05, 0.1 mu g g(-1)). The recovery level ranged from 93.99% to 101.49% and 90.59% to 99.50% for lambda-cyhalothrin and cypermethrin respectively. The relative standard deviation values were less than 4% in all cases. The sensitivitiy of the method was acceptable with limits of detection (LOD) of 0.0025 mu g g(-1) and 0.01 mu g g(-1) for lambda-cyhalothrin and cypermethrin, respectively. Finally, the proposed method was applied successfully for residue determination of both lambda-cyhalothrin and cypermethrin in soil samples from an oil palm plantation in Labu, Negeri Sembilan, Malaysia

A modification of the BCR sequential extraction procedure to investigate the potential mobility of copper and zinc in shrimp aquaculture sludge

The mobility, bioavailability and persistence of copper and zinc were investigated by comparing the effect of concentration and pH changes in step 2 BCR (European Community Bureau of Reference, now known as the Standards Measurements and Testing Program) sequential extraction procedure in shrimp aquaculture farm sludge from Selangor, Malaysia. The pseudototal metal contents of shrimp aquaculture sludge samples were determined following an aqua regia digestion. The metal content in the extracts was measured by flame atomic absorption spectrometry (AAS). The concentration of Zn was increased with the increase in the concentration of hydroxylammonium chloride from 0.1 M to 0.5 M, However, further increase in the concentration of reductant caused a significant reduction in released Zn. Zinc showed the highest release percentage for hydroxylammonium chloride 0.5 M with pH 1.5 (modified BCR sequential extraction scheme). In contrast, Cu showed the highest speciation percentage in step 2 when the unmodified sequential extraction procedure was used. Copper and zinc concentrations in this sludge, however, were not higher than the typical concentrations in soil, hence the use of this sludge as a fertilizer is suitable

Cyclodextrin modified ionic liquid material as a modifier for cloud point extraction of phenolic compounds using spectrophotometry

A greener method based on cloud point extraction (CPE) in the presence of b-cyclodextrin (CPE-bCD) and β-cyclodextrin functionalized with ionic liquids (CPE- β CD-IL) systems were investigated and compared for the removal of 2,4,6-TCP and 4-NP in aqueous sample using UV-Vis spectrophotometric method. In the present study, β CD-IL modifier, was used in CPE- β CD-IL system as an enhancement in the removal of 2,4,6-TCP and 4-NP. The removal of 2,4,6-TCP and 4-NP were optimum at pH 7 with concentration of DC193C, 0.5 (v/v %), for this work. Apart from that, the removal process was found to be optimum at 10 mg L-1 of both modifies concentration. For the isotherm study, monolayer solubilization capacity is greater for 2,4,6-TCP than 4-NP. The performance of the β CD-IL modifier towards the hydrophilic 4-NP showed enhanced extraction efficiency in the present study as compared to the β -CD modifier. Finally, the interactions between the cavity of β CD-IL with 4-NP and DC193C were investigated and the results show that the inclusion of the complex formation, hydrogen bonding between DC193C and 4-NP, π- π interaction, electrostatic attraction between the imidazolium ring of the β CD-IL was the main interactions involved in the extraction process

International Nosocomial Infection Control Consortium report, data summary of 50 countries for 2010-2015: Device-associated module

•We report INICC device-associated module data of 50 countries from 2010-2015.•We collected prospective data from 861,284 patients in 703 ICUs for 3,506,562 days.•DA-HAI rates and bacterial resistance were higher in the INICC ICUs than in CDC-NHSN's.•Device utilization ratio in the INICC ICUs was similar to CDC-NHSN's. Background: We report the results of International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2010-December 2015 in 703 intensive care units (ICUs) in Latin America, Europe, Eastern Mediterranean, Southeast Asia, and Western Pacific. Methods: During the 6-year study period, using Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN) definitions for device-associated health care-associated infection (DA-HAI), we collected prospective data from 861,284 patients hospitalized in INICC hospital ICUs for an aggregate of 3,506,562 days. Results: Although device use in INICC ICUs was similar to that reported from CDC-NHSN ICUs, DA-HAI rates were higher in the INICC ICUs: in the INICC medical-surgical ICUs, the pooled rate of central line-associated bloodstream infection, 4.1 per 1,000 central line-days, was nearly 5-fold higher than the 0.8 per 1,000 central line-days reported from comparable US ICUs, the overall rate of ventilator-associated pneumonia was also higher, 13.1 versus 0.9 per 1,000 ventilator-days, as was the rate of catheter-associated urinary tract infection, 5.07 versus 1.7 per 1,000 catheter-days. From blood cultures samples, frequencies of resistance of Pseudomonas isolates to amikacin (29.87% vs 10%) and to imipenem (44.3% vs 26.1%), and of Klebsiella pneumoniae isolates to ceftazidime (73.2% vs 28.8%) and to imipenem (43.27% vs 12.8%) were also higher in the INICC ICUs compared with CDC-NHSN ICUs. Conclusions: Although DA-HAIs in INICC ICU patients continue to be higher than the rates reported in CDC-NSHN ICUs representing the developed world, we have observed a significant trend toward the reduction of DA-HAI rates in INICC ICUs as shown in each international report. It is INICC's main goal to continue facilitating education, training, and basic and cost-effective tools and resources, such as standardized forms and an online platform, to tackle this problem effectively and systematically