Removal of metals and inorganics from rendered fat using polyamine-modified cellulose nanocrystals.

Meatpacking and poultry operations produce an enormous amount of co-products including offal, fat, blood, feathers etc. that are collected and processed by the rendering industry into value-added materials such as various protein meals and rendered fat products. Rendered fats (mainly composed of triglycerides from the adipose tissue of animals or used cooking oil from the restaurant industry) are sold for a variety of applications including animal feed formulations. Nonetheless, in the current context of energy scarcity, their use as feedstocks for the generation of renewable fuels including biodiesel and renewable diesel represents a growing market. The diverse composition of the source material can impose significant challenges in terms of compliance, requiring the control (and reduction) of the concentration of elements such as phosphorus, sulfur, calcium, magnesium, sodium, potassium, and other undesirable metals that can otherwise interfere with critical aspects of the refining process or contaminate the renewable fuel products. To address this critical need, we describe the application of poly(ethylenimine)-modified cellulose nanocrystals as a low-cost material for the removal of unwanted metal/inorganic cations from rendered fat. A total of 28 real samples including poultry, white pork grease, and beef tallow were analyzed. Test results showed that the approach can effectively decrease the concentration of the target elements by 95 ± 2%, suggesting that this treatment protocol could dramatically improve the application of rendered fat products for renewable fuel refining.

Correction: Removal of metals and inorganics from rendered fat using polyamine-modified cellulose nanocrystals.

[This corrects the article DOI: 10.1039/D3SU00116D.].

Effectiveness of preoperative thoracic epidural testing strategies: a retrospective comparison of three commonly used testing methods.

PURPOSE: Thoracic epidural analgesia (TEA) is a well stablished technique for pain management in major thoracic and abdominal surgeries; however, it has considerable failure rates. Local anesthetic (LA) administration and subsequent assessment of sensory block through physical examination (e.g., decreased temperature perception determined via an LA temperature dissociation test [LATDT]) has been the historical standard for evaluation of thoracic epidural placement. Nevertheless, newer methods to objectively evaluate successful placement have recently been developed, e.g., the epidural electrical stimulation test (EEST) and epidural pressure waveform analysis (EWA). The purpose of this study was to evaluate the effectiveness of preoperative TEA catheter testing (LATDT, EEST, and EWA) on reducing TEA failure. METHODS: After obtaining an institutional research ethics board approval for a retrospective study, we conducted a single-institution retrospective review on all TEAs performed between January 2016 and December 2021. Patients were assigned to one of four groups based on the performed test method to verify the placement of the TEA catheter: no test, LATDT, EEST, and EWA. A TEA was deemed successful if it provided bilateral dermatomal sensory block to ice test in the postoperative period, and was used for patient analgesia for at least 24 hr. RESULTS: One thousand two hundred and forty-one patients submitted to preoperative TEA were included. Twenty-eight patients were excluded. Tested and untested epidurals had failure rates of 3.8% (95% confidence interval [CI], 1.8 to 6.2) and 11.5% (95% CI, 5.2 to 17.1), respectively (P < 0.001). CONCLUSION: Objective preoperative testing after placement of thoracic epidurals was associated with a reduction in failure rates.

RéSUMé: OBJECTIF: L'analgésie péridurale thoracique (APT) est une technique bien établie pour la prise en charge de la douleur dans les chirurgies thoraciques et abdominales majeures; cette modalité entraîne cependant des taux d'échec considérables. L'administration d'anesthésique local (AL) et l'évaluation subséquente du bloc sensitif par un examen physique (p. ex. diminution de la perception de la température déterminée par un test de dissociation de la température après l'AL [LATDT]) ont constitué la norme historique pour l'évaluation du positionnement de la péridurale thoracique. Néanmoins, de nouvelles méthodes permettant d'évaluer objectivement le positionnement réussi ont récemment été mises au point, par exemple le test de stimulation électrique péridurale (EEST) et l'analyse de la forme d'onde de pression péridurale (EWA). L'objectif de cette étude était d'évaluer l'efficacité des tests préopératoires de cathéters d'APT (LATDT, EEST et EWA) sur la réduction des échecs d'APT. MéTHODE: Après avoir obtenu l'approbation d'un comité d'éthique de la recherche de l'établissement pour une étude rétrospective, nous avons réalisé un examen rétrospectif monocentrique de toutes les APT réalisées entre janvier 2016 et décembre 2021. Les patient·es ont été assigné·es à l'un des quatre groupes en fonction de la méthode de test utilisée pour vérifier l'emplacement du cathéter d'APT, soit : aucun test, LATDT, EEST et EWA. Une APT a été jugée efficace si elle a fourni un bloc sensitif dermatomal bilatéral au test de glace en postopératoire et a été utilisée pour l'analgésie pendant au moins 24 heures. RéSULTATS: Mille deux cent quarante et un·e patient·es soumis·es à une APT préopératoire ont été inclus·es. Vingt-huit personnes ont été exclues. Les péridurales testées et non testées présentaient des taux d'échec de 3,8 % (intervalle de confiance [IC] à 95 %, 1,8 à 6,2) et de 11,5 % (IC 95 %, 5,2 à 17,1), respectivement (P < 0,001). CONCLUSION: Les tests préopératoires objectifs après la mise en place de péridurales thoraciques ont été associés à une réduction des taux d'échec.

3D-printed device for the kinetic determination of As(III) in groundwater samples by digital movie analysis.

High concentrations of inorganic arsenic in groundwater for human consumption is a worldwide common problem. Particularly, the determination of As(III) becomes important, since this species is more toxic than organic, pentavalent and elemental arsenic forms. In this work, a 3D-printed device that included a 24-well microplate was developed to perform the colourimetric kinetic determination of arsenic (III) by digital movie analysis. A smartphone camera attached to the device was used to take the movie during the process where As(III) inhibited the decolourization of methyl orange. The movie images were subsequently transformed from RGB to YIQ space to obtain a new analytical parameter called "d", which was related to the chrominance of the image. Then, this parameter allowed the determination of the inhibition time of reaction (tin), which was linearly correlated with the concentration of As(III). A linear calibration curve (R = 0.9995) in the range from 5 µg L-1 to 200 µg L-1 was obtained. The method was precise (RSD = 1.2%), and the limits of detection (LOD) and quantification (LOQ) were 1.47 µg L-1 and 4.44 µg L-1, respectively. These values were lower than the limit established by the World Health Organization for total arsenic in drinking water (10 µg L-1). The accuracy of the method was assessed by a recovery study with optimal results (94.3%-104.0%). Additionally, the Analytical GREEnness metric approach was applied, obtaining a score 1.7 times higher than previously published works. The method is simple, portable and low-cost, being in compliance with various principles of green analytical chemistry.

Brand new Dual Absorption and Emission Smartphone-Based Spectrophotometer (DAESS) for the study of the role of water in the preparation of Natural Deep Eutectic Solvents.

Natural Deep Eutectic Solvents (NADES) are highly important for Green Chemistry principles and can be used instead of harmful organic solvents. Indeed, nowadays smartphone-based analytical devices can replace some traditional laboratory equipment. In the present work, a smartphone based dual spectrophotometer and spectrofluorometer device was designed, 3D manufactured, and validated. A resolution of 0.241 ± 0.010 pixel.nm-1 and a stability comparable with commercial instruments were obtained. Using the proposed device it was possible, for the first time, to study the role of water in NADES (fructose:urea:water) preparation, by testing the influence of structural and dilution water. In this sense, it was observed that when water was added before NADES preparation (integrated into the superstructure of the solvent), fluorescence and absorbance intensities sharply decayed (up to 90% and 95%, respectively). In contrast, dilution water had minor effects on spectroscopic features of the eutectic system, which was expressed as 29% and 23% of diminution of signal intensities for both techniques. The obtained results suggest that the moment the water is added plays a significant role in NADES properties.

Use of universal 3D-Printed smartphone spectrophotometer to develop a time-based analysis for hypochlorite.

A fully-functional smartphone-based spectrophotometer was designed and built using 3D printing. The major advantage of this approach is its capacity to be interfaced with a variety of smartphones, allowing the use of the smartphone's camera and display, and regardless of the relative position of the camera. The analytical performance of the device was analyzed using a model dye (crystal violet), leading to a proportional response for concentrations in the 0.06-15.0 mg L-1 range, with a variability of 1.0% (intra-day) and 2.6% (inter-day). To demonstrate the functionality of the device, the degradation process of the dye by sodium hypochlorite was studied. The results obtained were applied to develop a paper-based test for NaClO in sanitation solutions, in which the time required to bleach the dye was used to estimate the concentration of the solution. This device represents a simple and inexpensive tool for everyday laboratory use and could address important analytical challenges in low-income communities and features a versatile arrangement, that is compatible with a wide variety of smartphones and software platforms.

New, inexpensive and simple 3D printable device for nephelometric and fluorimetric determination based on smartphone sensing.

A new, inexpensive and easy to use 3D printable device was developed for nephelometric and fluorimetric determination. Its applicability was tested for the quantification of quinine in tonic drinks and sulfate in natural water with good analytical accuracy. In this way, sulfate determination was carried out by nephelometry using a red LED, while quinine was determined using a blue LED by fluorimetry. A smartphone camera was used to take the pictures and afterwards transform them into the RGB color space using the software ImageJ by a personal computer. The linear range was 2.0-50.0 mg L-1 for sulfate with a LOD of 0.13 mg L-1, and the corresponding quantification limit (LOQ) was 0.43 mg L-1. The linear range for quinine was from 0.42 to 3.10 mg L-1. The LOD and LOQ were 0.11 mg L-1 and 0.38 mg L-1, respectively.

Flow injection analysis: Rayleigh light scattering technique for total protein determination.

A novel flow injection analysis (FIA) method with Rayleigh light scattering (RLS) detection was developed for the determination of total protein concentrations. This method is based on the weak intensity of RLS of bromothymol blue (BB) (3',3"-dibromothymolsulfonephthalein) which can be enhanced by the addition of protein in weakly acidic solution. A common spectrofluorimeter was used as a detector. It was proved that the application of this method to quantify the total proteins in real samples by using bovine serum albumin was possible. The RLS signal was detected at lambda(ex)= lambda(em)=572 nm. The linear range was 7.0-70.0 microg mL(-1), the detection limit was 3.75 microg mL(-1), the reproducibility was 5.5% (n=7), and the sample throughput was 26 h(-1).