Use Of Glassware Research Articles

HILIC UPLC/ QTof MS Method Development for the Quantification of AGEs Inhibitors - Trouble Shooting Protocol.

The paper reports an attempt to develop and validate a HILIC UPLC/ QTof MS method for quantifying N-ε-carboxymethyl-L-lysine (CML) in vitro, testing N-ε- carboxy[D2]methyl-L-lysine (d2-CML), and N-ε-carboxy[4,4,5,5-D4]methyl-L-lysine (d4-CML) as internal standards. During the method development, several challenging questions occurred that hindered the successful completion of the method. The study emphasizes the impact of issues, generally overlooked in the development of similar analytical protocols. For instance, the use of glassware and plasticware was critical for the accurate quantification of CML. Moreover, the origin of atypical variation in the response of the deuterated internal standards, though widely used in other experimental procedures, was investigated. A narrative description of the systematic approach used to address the various drawbacks during the analytical method development and validation is presented. Reporting those findings can be considered beneficial while bringing an insightful notion about critical factors and potential interferences. Therefore, some conclusion and ideas can be drawn from these trouble-shooting questions, which might help other researchers to develop more reliable bioanalytical methods, or to raise their awareness of stumbling blocks along the way.

SICAK CAM ÜFLEME TEKNİĞİNDE ODUN KÜLÜ KULLANIMININ ESTETİK İFADE OLANAKLARININ ARAŞTIRILMASI

Glass has passed some important phases throughout history. The development process that began with the discovery of glass in about 3500 years ago has enabled glass to spread to wider masses with the discovery of hot glass blowing. Later, the use of glassware became widespread with the development of crystal glass and the beginning of low cost glass production. The most important turning point is the movement of the studio glass, which was about 100 years ago. Glass is a material used for decorative purposes from ancient civilizations to day-to-day. Nature has spontaneously produced glassware and the natural glass called obsidian has been used in the construction of various tools since ancient times. With the development of technology, the production of glass industry has started and at the same time, with the development of studio glassware, hot glass forming has made itself a technique in glass arts. In this study, the effect of wood ash on hot glass formation was investigated in order to investigate surface effects in hot glass technique. According to the results obtained, it has been shown that wood ash, which has many advantages such as having very fine particles, high avaliability and high reactivity, can be used in hot glass technique as a eco-friendly decoration material.

Vitamin Fortification of Fluid Milk.

Vitamin concentrates with vitamins A and D are used for fortification of fluid milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of fluid milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in fluid milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of fluid milk.

Experimental Investigation of the Coprecipitation Method: An Approach to Obtain Magnetite and Maghemite Nanoparticles with Improved Properties

Iron oxides that exhibit magnetic properties have been widely studied not only from an academic standpoint, but also for numerous applications in different fields of knowledge, such as biomedical and technological research. In this work, magnetite and maghemite nanoparticles were synthesized by chemical coprecipitation of FeCl2·4H2O and FeCl3·6H2O (proportion of 1 : 2) in three different cases using two bases (sodium hydroxide and hydroxide ammonium) as precipitants. The chemical coprecipitation method was selected for its simplicity, convenience, reproducibility, and low cost in the use of glassware. The nanostructured materials were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD) and magnetometry (VSM). The objective of this work is to study the variation in the morphological characteristics and physical properties of nanoparticles magnetic as a function of the different production processes. As observed by TEM, the materials obtained from the precipitating agent NH4OH are more uniform than those obtained with NaOH. From XRD pattern analysis, it appears that the obtained materials correspond to magnetite and maghemite and, from magnetometry VSM analysis, show high magnetization as a function of the magnetic field at room temperature, indicating that these materials are superparamagnetic.

“The Price is Right” for Your Classroom

An initial goal of chemistry laboratory courses is almost always the “proper” use of laboratory resources including glassware and instruments. The proper use of glassware encompasses many topics, s...

Quality criteria of the isotope dilution method for the determination of polycyclic aromatic hydrocarbons, petroleum-derived hydrocarbons and phenol in leachate of large-scale lysimeter experiments

A comprehensive analytical procedure for polycyclic aromatic hydrocarbons, petroleum-derived hydrocarbons and phenol using the isotope dilution method and employing high-resolution gas chromatography and mass spectrometry was developed and validated for leachates from source-term experiments and the different sampling sites of lysimeters. The use of glassware and other materials is efficiently limited to minimize the risk of contamination. The relative standard deviation elaborated allows precise reliable measurements. Limit of detection and recovery data are useful to judge the quality of each single measurement.

Silica fouling and cleaning of reverse osmosis membranes

Desalination plays an important role in producing pure water from brackish water. Reverse osmosis (RO) is by far the most efficient way to remove colloidal and dissolved silica, which can be found in high concentrations in brackish water. The presence of silica and its ability to foul membranes limits the use of silica bearing waters for desalination and when used, it has many economic penalties. This study examines the effect of silica polymerisation in the presence of polyvalent cations and anions in RO systems. Source of silica in the experimentation was from commercial grade sodium metasilicate (Na2O3Si.9H2O). The membranes used were polyamide and thin film manufactured by Osmonics. Use of glassware is minimised to avoid the possibility of any contribution by silica leaching into solution. The feed solution consists of silica, calcium and magnesium ions in various concentrations to determine the effect of polyvalent ions on polymerisation and the appropriate pre-treatment technology. The experiment was set up in a way as to simulate the conditions that would be encountered in a desalination plant. Concentration polarisation (C/P) in the system was experimentally determined with a simple technique that was developed and its effects on fouling are examined. In addition tests were carried out to examine the actual fouling mechanism in reverse osmosis units under various experimental conditions. Furthermore the effect of cleaning, with distilled water and with pulsations as well as with commercially available cleaners were examined. Some commercially available cleaners were capable at partially restoring the flux. Further investigation is underway to examine the effectiveness of new silica specific inhibitors.

Phthalate Esters in Sediments Near a Sewage Treatment Plant Outflow in Hamilton Harbour, Ontario: SFE Extraction and Environmental Distribution

Esters of phthalic acid are ubiquitous environmental contaminants as a result of their use as plasticizers and as constituents in many other commercial products. Although the acute toxicity of phthalates is low, recent concerns over their potential to disrupt the gonadal development of vertebrates has prompted interest in determining the distribution of these compounds in the environment. However, trace analysis of phthalates in environmental samples has been hampered by their presence as ubiquitous laboratory contaminants. In this study, the problem of high background contamination was addressed by developing an analytical method using supercritical fluid extraction (SFE), which was used to extract phthalates from sediment samples collected near the outflow of a sewage treatment plant (STP) in Hamilton Harbour at the western end of Lake Ontario. GC-MS-SIM analysis of sediment samples indicated that di(2-ethylhexyl) phthalate (DEHP)was present at very high concentrations; ranging from a mean of 29.7 μg/g dry weight at a site near the STP outflow to a mean of 6.5 μg/g dry weight at a site 300 m away. Di-n-butyl phthalate (DBP), and benzylbutyl phthalate (BBP) were judged to be present in some sediment samples but at concentrations below the Method Detection Limits (< 0.3 μg/g). Di-isononyl phthalate (DINP) and diethyl phthalate (DEP) were not detected in any of the sediment samples. This study indicates that SFE can be an efficient extraction method for phthalates in sediments, which avoids the extensive use of glassware and organic solvents that may contaminate environmental samples. In addition, STP effluents are sources of phthalates in the aquatic environment; in particular, DEHP.

NOx Contamination in Laboratory Ware and Effect of Countermeasures

Contamination of various types of laboratory wares with NOx (NO−2 and NO−3) was assessed systematically and the effect of extensive washing as a countermeasure was evaluated. Mean NOx contamination arising from a model procedure for NOx determination in plasma was 0.93 μM (range, 0.35–1.49 μM). The major source of contamination included conical tubes (54.8%) and pipette tips used for transfer of solution (12.3–16.3%). Except for soft glassware, most NOx contamination could be washed out by pure water. Although NOx contamination in respective laboratory wares could be reduced below detection levels by extensive washing, summation of the contamination through the model procedure could not be completely abolished (but the effect of washing persisted at least 10 days). Heavy contamination was noted in glassware (especially soft glass) and ultrafiltration units, which was difficult to remove. Several types of vacuum blood sampling tubes contained various levels of NOx. Our results indicated that a small but significant amount of contamination remained in laboratory ware even after extensive washing, and that it is advisable to avoid the use of glassware (soft glass), ultrafiltration units, and vacuum blood sampling tubes during the processing of clinical sampling for the measurement of NOx.

Simultaneous Quantitative Determination Method for Sphingolipid Metabolites by Liquid Chromatography/Ionspray Ionization Tandem Mass Spectrometry

Sphingolipid metabolites ceramide, sphingomyelin, sphingosine, psycosine, sphingosylphosphorylcholine, and dimethylsphingosine were separated and simultaneously quantitated by liquid chromatography/ionspray ionization tandem mass spectrometry (LC/MS/MS). The use of glassware throughout minimized losses due to adsorption and the pretreatment of this method consisted of simple liquid–liquid extraction procedure with a mixture of chloroform and methanol. After separation on a short C18silica column eluted in a gradient mode, the metabolites were detected by MS/MS. This assay allows simultaneously quantification of these metabolites over a range of at least 0.1 to 100 ng/106cells. The LC/MS/MS analyses took 10 to 15 min per sample and we could examine up to 50 samples per day. We also detected endogenous sphingosine 1-phosphate in HL-60 cells. The utility of the method was demonstrated by examining changes in metabolites levels in HL-60 cells after treatment with sphingomyelinase. It was found that sphingomyelinase fromBacillus cereusmay have selectivity for acyl chain length.

Quality Assurance in Mycotoxin Analysis

Mycotoxin analysis in food and biological fluids is receiving more and more concern, in view also of increasing involvement by the European Union regarding legislation. Basically all the analytical steps regarding mycotoxin analysis have to be performed according to accurate criteria which are strictly connected to the quality of results in terms of reliability. The only rationale for reducing this difficulty is to apply quality assurance principles. Quality assurance principles define, in fact, the rules to be observed for performing this analysis with a degree of uncertainty that is as low as may be possible. In particular sampling techniques, if carried out improperly, give rise to uncertainty concerning the representativeness of samples that is so critical as to induce a dramatic source of errors in the final analysis. Therefore it seems appropriate to plan training courses for personnel on the various side-effects related to the available sampling and subsampling techniques depending on the commodity. Other contributions to the overall error derive from improper methodologies used by technicians in the pre-treatment step of the samples (incorrect use of glassware, standard solutions, etc.), and finally from the operations involved in the whole analytical procedure. In addition, the use of reference materials and certified reference materials together with the utilization of validated methods of analysis will be dealt with as concrete procedures for obtaining the certainty of final results of good quality. This aspect takes on a relevant outcome if applied to official control activities from authorized bodies acting at a national level.

A colorimetric modification of McLean's method for the determination of phosphorus in soils

AbstractMcLean's technique of extraction of soil phosphate by digestion of soil with concentrated sulphuric and nitric acids has been adapted to a colorimetric method of determining soil phosphate by use of metol. The complete technique is performed with use of glassware alone and is simple and accurate.

A Comparison of the Volumetric and Gravimetric Methods for Bacteriological Examination of Ice Cream

A bacteriological analysis of ice cream presents certain difficulties which hinder the procurement of a fair sample. Obviously, the air incorporated in the product must be completely expelled if uniform results from volumetric (1or 10-cc.) samples are to be expected. On the other hand, if the analysis is made on a gravimetric basis (10-gram), the sample need only be melted sufficiently to enable thorough shaking. Variation in the viscosity of different ice cream mixes and the use of glassware that is not chemically clean results in more or less of the mix adhering to the pipette. With a volumetric sample this may offer a source of considerable variation, whereas with a gravimetric portion it does not matter how much mix adheres to the pipette or how much air is retained in the product. There has been some question in the minds of those who make bacterial determinations on ice cream as to whether the advantages of the gravimetric sample justify the extra time and work involved. The use of the gravimetric method necessitates careful counter-balancing of the dilution blank, followed by carefully weighing 10 grams of the melted ice cream. The two operations with the balances are both time consuming and tedious. Boning and his associates (4) found that the gravimetric method required 77 per cent more time than the volumetric procedure and concluded that, equally accurate counts could be obtained by either method. The extra labor involved in the gravimetric method would be justified only if the results were less variable than would be obtain-