Duration Of Centrifugation Research Articles

Shifting shapes: Density variations and physicochemical characteristics from spheres to rods

This work extensively explores purifying cetyltrimethylammonium bromide (CTAB)-stabilized gold nanorods, focusing on efficiently separating spheres and rods to achieve a rod-rich suspension in one cycle. Utilizing UV–vis spectroscopy and Helium ion microscopy, the study delves into nanorods' spectral traits across different aspect ratios (AR 3–6). Results show centrifugation greatly influences gold nanorods' spectral features, indicating a link between CTAB-coated nanorod density and absorbance levels post-centrifugation. This quantitative evaluation enhances understanding of purification dynamics, highlighting effects on purity and density while offering insights for future refinements. Emphasizing centrifugation's role in reducing byproducts, nanoparticle density changes, and absorbance variations, the study's consistent spectral profiles affirm the effectiveness of purification parameters for stability and nanoparticle density maintenance. By quantitatively analyzing centrifugation duration's impact on spectral properties and shape separation dynamics, the research provides an empirical foundation for optimizing gold nanorod suspension purification processes. Additionally, a clear correlation between AR and absorbance-to-density ratios pre- and post-centrifugation underscores AR's relevance in comprehending nanorods' optical traits amidst centrifugation, benefiting purification strategies.

An investigation of a proposed freezing desalination system integrating sweating effect and a Centrifugal-Based brine rejection technique

Freeze desalination (FD) presents a promising yet underutilized technique for addressing global water scarcity, hindered by challenges such as the necessity for ice crushing and washing. This study introduces an innovative FD system incorporating sweating effects and centrifugal brine rejection, aiming to simplify the process by eliminating these additional steps. We evaluate the impact of key variables including sweating period, centrifugation duration, and rotational velocity on ice quality and process efficiency. Through systematic examination, our findings reveal that the sweating period significantly influences product salinity and salt rejection efficiency, achieving a salinity reduction from 40 ppt to 0.99 ppt with a 95.05 % salt rejection rate. Additionally, the centrifugation method showcased low power consumption, marking a significant advancement towards more sustainable desalination practices. This research not only demonstrates the feasibility of the proposed FD system but also sets the groundwork for future enhancements in the field of desalination technology.

Anisaldehyde-based deep eutectic solvent dispersive liquid–liquid microextraction (DES-DLLME) followed by UPLC–MS/MS for simultaneous determination of selected parabens and bisphenols in food products: Method development and assessment of the ecological implications

A rapid and environmentally friendly method based on dispersive liquid–liquid microextraction (DLLME) technique, coupled with UPLC–MS/MS analysis was employed for simultaneous determination of selected bisphenols and parabens residues in food products. In this research, anisaldehyde and decanoic acid with a molar ration of 3:1 was prepared as a natural deep eutectic extracting solvent. Various extraction parameters such as the volume of the natural deep eutectic solvent, vortex duration, centrifugation duration, sample volume and pH were systematically explored and optimized. Determination coefficients of ≥0.9990 were achieved for the analyzed compounds under the optimal conditions. The limits detection were in the range of 0.0005 to 0.02 µg/L, while extraction recoveries ranged from 97.8 % to 100.2 % with relative standard deviations (%RSD) not exceeding 6.8 %. To assess the practical applicability of the proposed method, it was employed for the determination of five parabens and three bisphenols in eighty food products including soft drinks, energy drinks, sauces and juices collected from the Saudi market. The environmental implications of the proposed method were assessed using the following evaluation tools, Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical GREEnness metric (AGREE). To the best of our knowledge, this is the first study to determine the investigated analytes using anisaldehyde based deep eutectic solvent.

Optimized conditions for gene transduction into primary immune cells using viral vectors

Chimeric antigen receptor (CAR) T cell therapy has emerged as a promising modality for anti-cancer treatment. Its efficacy is quite remarkable in hematological tumors. Owing to their excellent clinical results, gene- modified cell therapies, including T cells, natural killer (NK) cells, and macrophages, are being actively studied in both academia and industry. However, the protocol to make CAR immune cells is too complicated, so it is still unclear how to efficiently produce the potent CAR immune cells. To manufacture effective CAR immune cells, we need to be aware of not only how to obtain highly infective viral particles, but also how to transduce CAR genes into immune cells. In this paper, we provide detailed information on spinoculation, which is one of the best known protocols to transduce genes into immune cells, in a methodological view. Our data indicate that gene transduction is significantly dependent on speed and duration of centrifugation, concentration and number of viral particles, the concentration of polybrene, and number of infected immune cells. In addition, we investigated on the optimal polyethylene glycol (PEG) solution to concentrate the viral supernatant and the optimized DNA ratios transfected into 293T cells to produce high titer of viral particles. This study provides useful information for practical production of the gene-modified immune cells using viral vectors.

Estimation of the Mechanical Properties of PRF in the Implant Surgery: An Original Research.

In many oral procedures that involve the implants, hair implantations, "Platelet-Rich Fibrin Membrane (PRF)" is commonly applied. The advantages are many. In this study, the mechanical resistance of PRF under resistance pull on a longitudinal axis was assessed and compared. For the current in vitro study, 60 volunteers donated each 10 ml of their blood and hence a total volume of 600 ml of blood was procured that was analyzed for the current study. The total volume was grouped to three groups where they receive three resistance centrifugation forces of "F-200,600,800 m/s²." In each group, 20 samples were tested for each level of the G-resistance. Each group was further divided as two subgroups of different times of wait, where they were centrifuged at baseline time and after a stand of 30 minutes. On universal testing equipment, the PRF membranes were mechanically tensioned in order to determine each membrane's resistance force. These values were compared for any statistical variance using appropriate statistical tools keeping P < 0.05. Any applied force had no statistically significant effect on the centrifugation duration for membrane resistance. When the resistance was applied for the PRP samples immediately after they were procured, no significant variation was seen at all the grades of the centrifugation forces; consequently, the T30 group showed a statistically significant variance for the centrifugation forces applied (P = 0.04), with the highest value when the greatest force was applied. According to the results, the centrifugation waiting period could be determined based on the application requirement. For immediate membrane usage, the centrifugation had no effect on resistance; however, after 30 minutes, a membrane with greater resistance was produced by applying more force.

Development of a Liquid-Phase Microextraction Method Prior to HPLC Analysis of Quercetin in Food Samples.

In this research, an efficient, fast, low-cost and easy-to-use liquid-phase microextraction method was established to measure quercetin in onion and tomato before analysis by HPLC instrument. Herein, a rotatable central composite design-response surface methodology and artificial neural network were applied to model, optimize and predict the affecting factors on the microextraction procedure. Here, a minimal level of extractant was applied in the absence of a disperser. The cloudy state was formed by repeatedly suctioning and injecting the mixture of the aqueous solution and extractant with a glass syringe. Due to this procedure, a turbid solution composed of the very fine droplets of extractant dispersed in the aqueous solution was created, the contact surface was significantly enlarged and the quercetin was promptly extracted. The optimum values for the proposed method included 284μL of 1-undecanol as the organic extractive solvent, pH of sample 3.3, the number of air injected nine times and speed and duration of centrifugation 4,000rpm and 5min. The linear range and detection of limit were achieved at 20-4,000 and 6μgL-1, respectively. RSD% was obtained ˂4.93% (n = 5). This model was applied to monitor quercetin in tomato and onion samples.

The Effect of Centrifuge Duration on Fat Graft Survival.

Background Although fat grafts are widely used for reconstruction and aesthetic purposes, their survival rates differ significantly. Centrifugation is one of the methods used to increase the survival of fat grafts. However, experimental studies examining the long-term outcomes of centrifugation duration are currently limited. Thus, in the present study, the effects of centrifugation duration on the survival of fat grafts were assessed using an animal model. Methods Thirty Sprague Dawley rats were included in the study and fat grafts were obtained from each specimen by excision from inguinal fat pads. Preparation protocols were administered as an en-bloc fat graft in Group 1, minced fat graft in Group 2, and fat graft centrifuged at 1,054 ×g for 2 minutes, 3 minutes, and 4 minutes in Group 3, 4, and 5, respectively. After 12 weeks of follow-up, grafts were harvested and were subjected to histopathological evaluation based on an established scoring system. Results En-block fat grafts were associated with necrosis, fibrosis, inflammation, vacuole formation, and alterations in adipocyte morphology. Among the three centrifugation groups, Group 3 demonstrated the best adipocyte viability and vascularity. However, graft weights decreased in all experimental groups. Conclusion The centrifugation process may have positive effects on adipocyte survival by means of purifying the fat graft and increasing adipocyte concentration. When the centrifugal durations were compared, 3-minute centrifuge yielded the most favorable results.

Review Pemilihan Adsorben Pada Proses Bleaching Dalam Metode Pemurnian Minyak Ikan

Bleaching is one of the processes in fish oil purification methods. In the bleaching process, it is necessary to use an adsorbent in the form of bleaching earth. This review article aims to review the various adsorbents that are most often used in fish oil purification methods. The review method in this article uses searches with search engines such as Google Scholar and Pubmed. Based on the search found below, there are several types of adsorbents that are most often used for the bleaching process in refining fish oil, namely Bentonite (Activated Charcoal), Magnesol XL, and Zeolite. Based on the three adsorbents found, each type has advantages and disadvantages which depend on the method used, temperature, speed and duration of centrifugation in the bleaching process.

Paralytic Impact of Centrifugation on Human Neutrophils.

Centrifugation is a common step in most of the popular protocols for the isolation of neutrophils from whole blood. Inconsistent results from previous studies on neutrophils may originate from an underestimation of the centrifugation effect, as in consequence impaired, not native cells, being investigated. We hypothesize, that centrifugation significantly impairs major neutrophil functions. However, there is no data yet whether the application of g-force itself or the product of g-force and duration of centrifugation (="g-time") defines the impact on neutrophils. Neutrophils were isolated from whole blood via centrifugation with different g-times and subsequently analyzed via live cell imaging for migration, as well as via flow cytometry for oxidative burst and surface antigen expression. Chemotactic migration was significantly reduced with increasing g-time. Oxidative burst decreased likewise the higher the g-time applied. Expression of CD11b was no longer upregulated in response to an n-formylmethionine-leucyl-phenylalanine (fMLP) stimulus in neutrophils having experienced high g-time during the isolation process. We conclude that centrifugation "paralyzes" neutrophils in the form of a significant decrease in functionality. Future investigations on neutrophil granulocytes should reduce the g-time load as far as possible.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis.

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Determination of Sudan III in Food by Supramolecular Microextraction and Spectrophotometry

A novel, accurate, and rapid procedure is reported using supramolecular liquid-phase microextraction of Sudan III combined with spectrophotometric detection at 510 nm. Analytical conditions such as the pH, supramolecular solvent volume, tetrahydrofuran (THF) volume, ultrasonication and centrifugation duration, initial and final sample volumes, and matrix effects were optimized. The quantitative recovery of Sudan III was obtained at pH 4.0. The relative standard deviation was less than 5%. The preconcentration factor was 33. The limits of detection and quantification were 0.79 μg L−1 and 2.6 μg L−1, respectively. The presented microextraction procedure was applied to determination of Sudan III in fortified spices including sumac, pepper flakes, soy sauce, and chili powder.

Optimized purification procedure for Iranian calcium bentonite for producing montmorillonite nanosheets

AbstractIn polymer composites, montmorillonite nanosheets are crucial as fire retardants, reinforcers, anti-corrosives, detoxifying agents and ultraviolet-protection agents. However, the quality of montmorillonite nanosheets can be improved by optimizing the raw bentonite purification process in which undesirable phases are removed. Optimization of Iranian calcium bentonite purification for nanomontmorillonite synthesis considering various parameters based on various physical approaches to dispersion and ultrasonication was investigated; the calcium bentonite purification was performed using sodium hexametaphosphate followed by either sedimentation or centrifugation, and the nanomontmorillonite synthesis was performed using ultrasonic treatment. The effects of suspension concentration, milling type, pH and centrifugation duration and speed on the separation of various impure phases were evaluated qualitatively and optimized. The raw and purified bentonite and the synthesized nanomontmorillonite were characterized using X-ray powder diffraction, X-ray fluorescence spectroscopy, Fourier-transform infrared spectroscopy and scanning electron microscopy. The cation-exchange capacity was also measured in the raw and purified samples. Optimal experimental conditions in the dispersed samples were achieved at a 2.5 wt.% concentration of bentonite suspension and planetary milling at pH 7. While the ultrasonic treatment was more effective than the dispersion approach for cristobalite elimination, a smaller lateral size of the montmorillonite sheets, optimized at 0.5 wt.% concentration of the suspension, was achieved. The increased cation-exchange capacity after the purification improved the exfoliation and delamination of montmorillonite nanosheets in the presence of cetyltrimethylammonium bromide as the surfactant. The interplanar spacing of (001) planes of 15 Å in raw bentonite shifted to 21 Å and 19 Å in purified and non-purified samples, respectively, after synthesis.

Practical and Robust NMR-Based Metabolic Phenotyping of Gut Health in Early Life.

While substantial efforts have been made to optimize and standardize fecal metabolomics for studies in adults, the development of a standard protocol to analyze infant feces is, however, still lagging behind. Here, we present the development of a hands-on and robust protocol for proton 1H NMR spectroscopy of infant feces. The influence of extraction solvent, dilution ratio, homogenization method, filtration, and duration of centrifugation on the biochemical composition of infant feces was carefully evaluated using visual inspection of 1H NMR spectra in combination with multivariate statistical modeling. The optimal metabolomics protocol was subsequently applied on feces from seven infants collected at 8 weeks, 4, and 9 months of age. Interindividual variation was exceeding the variation induced by different fecal sample preparation methods, except for filtration. We recommend extracting fecal samples using water with a dilution ratio of 1:5 feces-to-water to homogenize using bead beating and to remove particulates using centrifugation. Samples collected from infants aged 8 weeks and 4 months showed elevated concentrations of milk oligosaccharide derivatives and lactic acid, whereas short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) were higher in the 9 month samples. The established protocol enables hands-on and robust analyses of the infant gut metabolome. The wide-ranging application of this protocol will facilitate interlaboratory comparison of infants’ metabolic profiles and finally aid in a better understanding of infant gut health.

A Modified Preparation Method of Ideal Platelet-Rich Fibrin Matrix From Whole Blood.

One bioproduct that is widely used in the wound healing process is platelet-rich plasma (PRP). PRP is a liquid solution with high autologous platelet concentration, making it a good source of growth factors to accelerate wound healing. Recent development in PRP had created a new product called platelet-rich fibrin matrix (PRFM), which has a denser and more flexible structure. PRFM is the newest generation of platelet concentrate with a fibrin matrix that holds platelet in it. The key concept in creating PRFM from PRP is the addition of CaCl2 followed by centrifugation, which converts fibrinogen to fibrin, and the fibrin cross-links to form a matrix that contains viable platelets. There are many commercially available kits to create PRFM, but they are often expensive and uneconomical. This research will test a modified method of making ideal PRFM from PRP without any commercial kits. The modified method will include determining the minimum level of CaCl2 used, the type of centrifuge, and the speed and duration of centrifugation. By performing a modified preparation method on five samples of whole blood, it was found that the ideal PRFM could be made by mixing PRP with 25 mM CaCl2 and centrifuging it at a speed of 2,264 × g for 25 min at room temperature. The PRP and PRFM platelet counts of this method tend to be lower than the platelet counts found in other studies. Although visually comparable, further study is needed to compare the performance of PRFMs made with this method and PRFMs made with commercial kits.

COMPARISON OF DIFFERENT METHODS OF CENTRIFUGATION FOR OPTIMUM PREPARATION OF PLATELET RICH PLASMA (PRP)&amp; FRAMING A CUSTOMIZED PRP PROTOCOL-AN INNOVATIVE APPROACH

Introduction:The rationale behind the therapeutic potential of the high concentration of platelets in PRP (Platelet Rich Plasma) for intervention procedures of soft tissue injuries is often challenged by the ability of the centrifugation methods followed in extracting the high quality PRP with prompt contented quantity too.This study aims to unravel the basic science of PRP preparation involved in centrifugation protocols, spin methods, speed and time duration of centrifugation to obtain consistent therapeutic platelets yield. Materials and Methods:30 participants were subjected to intervention procedures using PRP. For therapeutic purpose 3 centrifugation protocol types are followed. Ø Protocol 1-Conventional Old protocol Ø Protocol 2-Customised New protocol Ø Protocol 3-Spin Reversal of the routine -hard spin followed by soft spin The Platelets and WBC concentration and composition in the final autologous PRP sample harvested as a result of double centrifugation method are compared for quantity and efficiency. Results:The maximum PCF-3.21 times above baseline and PRR -64.21% are through new customized spin proving its efficiency. As determined by one-way ANOVA, there is statistically significant difference between the PROTOCOL groups (1,2,3) for the variables PRP platelet count, PRP Leucocytes, PCF, PRR. A Tukey post hoc test revealed that there is statistically significant value for Protocol 2 and Protocol 3 compared to the Protocol 1 for PRP platelet count, PCF and PRR whereas for PRP Leucocytes, there was a statistically significant difference between the Protocol 2 and Protocol 3 which again implicates the necessity of spin reversal in yielding better quantity of leucocytes. Conclusion:To produce PRP samples with consistent and reproducible compositionsof platelets and leucocytes with better quality control standard through a detailed, precise and stepwise description of the manufacturing protocol has been explained in our study. Our perspective is in standardizing a safe, simple protocol that can be followed to obtain an optimal consistent platelet yield without the use of commercial kits, which has been proved statistically too.

The comparison of platelet parameters in Platelet Rich Plasma (PRP) using Ethylenediaminetetraacetic Acid (EDTA) and Acid Citrate Dextrose (ACD) anticoagulants at Dr. Wahidin Sudirohusodo Hospital, Makassar, Indonesia

Background: Platelet Rich Plasma (PRP) is an autologous plasma with a platelet concentration above normal values. It contains high levels of growth factor, which plays an important role in tissue repair. The quality of PRP products is influenced by the platelet count, anticoagulants, speed, and centrifugation duration. This study aimed to determine the effectiveness of Ethylenediaminetetraacetic Acid (EDTA) and Acid Citrate Dextrose (ACD) in PRP preparation by measuring the platelet count (PLT) and platelet index (MPV and PDW).Methods: Experimental laboratory study involved 25 volunteers performed at Hasanuddin University Hospital from September-October 2020. The values of PLT, MPV, PDW were measured using Sysmex XS-800i®. The parameters comparison between EDTA and ACD groups was analyzed using an independent T-test. A comparison of pre and post centrifugation was using paired T-test (significant if p&lt;0.05). Data were analyzed using SPSS version 22 for Windows.Results: The mean PLT in the EDTA sample was significantly lower than ACD (539.10x103/µL vs. 769.8x103/µL; p&lt;0.05). Mean MPV and PDW in EDTA were significantly higher than ACD (10.7fL vs 8.9fL and 12.7fL vs 9,8fL; p&lt;0,001). However, the mean MPV and PDW in the ACD sample did not change significantly (p&gt;0.05).Conclusion: PRP with ACD had a higher platelet count than EDTA, without significant platelet index changes.ACD is a more effective anticoagulant for the preparation of PRP than EDTA.

Scale-up of green synthesis and characterization of silver nanoparticles using ethanol extract of Plantago major L. leaf and its antibacterial potential

Green synthesis of silver nanoparticles (Ag NPs) utilizing plant extracts has been widely optimized these days because of its eco-friendly, simple, and cost-effective manner. This present study was performed to evaluate the scale-up trial on synthesis parameter and centrifugation duration of Plantago major L. leaf ethanolic extract in the green synthesis of Ag NPs. Leaf extract concentration of 0.25%, 70 °C of temperature, 60 min of synthesis time, and 30 min of centrifugation time were concluded as the optimized scale-up condition of green synthesis. The scale-up trial resulted in spherical silver nanoparticles with an average size 12.2±5.11 nm, proven from various spectroscopic (UV–Vis, EDS, FTIR), microscopic observations (SEM, FE-TEM), and other observations (SAED, DLS, XRD). The synthesized Ag NPs also exhibit promising antibacterial activity against several tested bacteria at 20 μg mL−1 of dosage. This study offers nine times higher yield of the synthesized Ag NPs (107.2±6.82 mg) at about the same making time of smaller scale of green synthesis. Sufficient nanoparticles will provide flexibility to carry out its characterization in an efficient manner and further bioactivity test and/or formulation experiments, such as in cosmetics, medical ointments, and other pharmaceutical products.

Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate.

The removal of concentrated colour (around 5039 Pt-Co) and chemical oxygen demand (COD; around 4142 mg L-1) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L-1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient (R2 = 0.98 and 0.96) and predicted R2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.

Technical note: Accelerate coccolith size separation via repeated centrifugation

Abstract. Coccolithophores play a key role in the marine carbon cycle and ecosystem. The carbonate shells produced by coccolithophore, named as coccolith, could be well preserved in the marine sediment for millions of years and become an excellent archive for paleoclimate studies. The micro-filtering and sinking–decanting methods have been successfully designed for coccolith separation and promoted the development of geochemistry studies on coccolith, such as the stable isotopes and Sr / Ca ratio. However, these two methods are still not efficient enough for the sample-consuming methods. In this study, the trajectory of coccolith movement during a centrifugation process was calculated in theory and carefully tested by separations in practice. We offer a MATLAB code to estimate the appropriate parameter, angular velocity at a fixed centrifugation duration, for separating certain coccolith size fractions from bulk sediment. This work could improve the efficiency of coccolith separation, especially for the finest size fraction, and make it possible to carry out the clumped isotope and radio carbon analyses on coccoliths in sediment.

The Effects Of Speed And Duration Of Centrifugation On The Values of Some Commonly Measured Plasma Electrolytes

Centrifugation is a routine process in a clinical chemistry laboratory where blood specimens collected into anticoagulant containers are centrifuged to separate the plasma from the blood cells. This is done at various speeds, times and temperature which most times affect the quality of samples mainly due to haemolysis. World Health Organisation guidelines advocate for a maximum duration of 15 minutes as the centrifugation duration for separation of plasma. Various laboratories in this region adopt various speeds and duration for separation of blood samples without minding any possible effect it may have on the value of certain common analytes. This study was therefore designed to study the effect of different centrifugation speeds and duration (within the scope of the WHO centrifugation time guidelines) on the value of commonly measured analytes like sodium, potassium, chloride and bicarbonate. A cross-sectional study where blood was taken from 30 apparently healthy undergraduate volunteers after dividing the group into A and B of 15 subjects each. From the A group, blood specimens from each subject was separated based on the different centrifugation speeds and from the B group, blood specimens from each subject was separated based on different centrifugation times. The different samples from each subject were analysed for sodium, potassium, chloride and bicarbonate and this was done for all subjects. The mean values of all the analytes were about the same for the 1000 Revolutions per Minutes (RPM), 2000 RPM, 3000 RPM and 4000 RPM and so were the mean values of all the samples labelled 3 minutes, 6 minutes, 9 minutes, 12 minutes and 15 minutes. The differences in the means of the subgroups for group A and group B were statistically not significant. From this study, it can be advocated that plasma can be separated from whole blood samples at a maximum speed of 4000 RPM for 3 minutes duration without affecting the accuracy of most analytes and the introduction of this speed and duration will improve the quality assurance of laboratories in this region.