Vitamin E Acetate Determination in Vaping Liquids and Non-targeted Analysis of Vaping Emissions of Diluents of Concern, Vitamin E Acetate and Medium-Chain Triglycerides Oil

During the summer of 2019, cases of lung injury associated with vaping emerged in North America, including among individuals who reported exclusive use of nicotine vaping liquids. Once vitamin E acetate was identified as a potential causative agent a quantitative method based on a simple sample dilution, separation by gas chromatography and analysis by triple quadrupole mass spectrometry (GC MSMS) was developed. Method detection limit (MDL) and limit of quantification (LOQ) were determined at 0.159 µg/mL and 0.505 µg/mL, respectively. The analysis was performed on a subset of 203 commercially sourced nicotine containing vaping liquids of various flavour profile and nicotine range (nicotine free-59 mg/mL) from an internal inventory. The target analyte, Vitamin E Acetate, was not detected in any samples analyzed, as expected, given the reported detection in literature and high association of the chemical with cannabis and not nicotine containing vaping products.

Isolation and characterization of phosphate solubilizing bacteria from corn rhizosfer

The aim of this study was to isolate and characterize the Phosphate solubilizing bacteria from the rhizosphere of Zea mays L., Jeneponto Regency. This research was conducted in several stages; i.e, sampling, medium preparation, sample dilution, isolation, characterization in the form of gram staining, biochemical tests, and quantitative tests of phosphate solubility. Soil samples were diluted in 0.9% NaCl and soil containing microbes was isolated on the Picovskaya medium. Three isolates were obtained which could dissolve phosphate, namely J2KN1, J3KR2, and J3TG3 isolates. The isolates were generally round in shape with raised elevations, white, slimy, smooth, shiny surface, milky white, shape like coccus and bacillus, and gram-negative. Some of the isolates had positive motility, indole, voges, methyl red, glucose, and sucrose fermentation in the biochemical test. The quantitative tests of the ability to dissolve phosphate showed that J2KN1 isolate had the highest concentration of 51.1 μM, and the J3KR1 and J3TG3 isolates had a concentration of 45.2 μM and 37.6 μM, respectively.

Use of compressed sensing to expedite high-throughput diagnostic testing for COVID-19 and beyond

The rapid spread of SARS-CoV-2 has placed a significant burden on public health systems to provide rapid and accurate diagnostic testing highlighting the critical need for innovative testing approaches for future pandemics. In this study, we present a novel sample pooling procedure based on compressed sensing theory to accurately identify virally infected patients at high prevalence rates utilizing an innovative viral RNA extraction process to minimize sample dilution. At prevalence rates ranging from 0-14.3%, the number of tests required to identify the infection status of all patients was reduced by 75.6% as compared to conventional testing in primary human SARS-CoV-2 nasopharyngeal swabs and a coronavirus model system. Additionally, our modified pooling and RNA extraction process minimized sample dilution which remained constant as pool sizes increased. Our use of compressed sensing can be adapted to a wide variety of diagnostic testing applications to increase throughput for routine laboratory testing as well as a means to increase testing throughput to combat future pandemics.

SLIDE—Novel Approach to Apocrine Sweat Sampling for Lipid Profiling in Healthy Individuals

We designed a concept of 3D-printed attachment with porous glass filter disks—SLIDE (Sweat sampLIng DevicE) for easy sampling of apocrine sweat. By applying advanced mass spectrometry coupled with the liquid chromatography technique, the complex lipid profiles were measured to evaluate the reproducibility and robustness of this novel approach. Moreover, our in-depth statistical evaluation of the data provided an insight into the potential use of apocrine sweat as a novel and diagnostically relevant biofluid for clinical analyses. Data transformation using probabilistic quotient normalization (PQN) significantly improved the analytical characteristics and overcame the ‘sample dilution issue’ of the sampling. The lipidomic content of apocrine sweat from healthy subjects was described in terms of identification and quantitation. A total of 240 lipids across 15 classes were identified. The lipid concentrations varied from 10−10 to 10−4 mol/L. The most numerous class of lipids were ceramides (n = 61), while the free fatty acids were the most abundant ones (average concentrations of 10−5 mol/L). The main advantages of apocrine sweat microsampling include: (a) the non-invasiveness of the procedure and (b) the unique feature of apocrine sweat, reflecting metabolome and lipidome of the intracellular space and plasmatic membranes. The SLIDE application as a sampling technique of apocrine sweat brings a promising alternative, including various possibilities in modern clinical practice.

Investigasi pengaruh pengenceran sampel madu pada proses klasifikasi madu menggunakan uv spectroscopy dan kemometrika

One form of honey adulteration is label adulteration for some premium honey such as uniflora honey from the honeybee species Trigona sp. One of the analytical methods that are currently developing and have the potential to perform the classification of premium honey in Indonesia is the UV spectroscopy method. In this study, an investigation was carried out on the effect of dilution on the performance of UV spectroscopy in the process of classifying Indonesian honey with different honeybees. A total of 4 types of honey samples with 10 samples each were used in this study. The honey sample was then diluted using distilled water. Each type of honey was given two dilution treatments, namely 1:20 (volume: volume) dilution of 5 samples and 1:40 (volume: volume) dilution of 5 samples. Spectral data were taken using a UV-visible spectrometer with a wavelength of 190-1100 nm (Genesys™ 10S UV-Vis, Thermo Scientific, USA) using the transmittance mode. The results of spectra analysis generally show that the sample with a 1:20 dilution has a higher absorbance intensity for both the original and modified spectra. The PCA results for each dilution showed that the honey samples could be separated into four different clusters for both 1:20 and 1:40 dilutions. The results of PCA analysis using all samples showed that the honey samples were classified into eight different clusters showing a significant effect of differences in honey sample dilution on the classification process of honey samples based on differences in the types of honeybees.

Toward Community Surveillance: Detecting Intact SARS-CoV-2 Using Exogeneous Oligonucleotide Labels

The persistence of the COVID-19 pandemic demands a dramatic increase in testing efficiency. Testing pooled samples for SARS-CoV-2 could meet this need; however, the sensitivity of RT-qPCR, the gold standard, significantly decreases with an increasing number of samples pooled. Here, we introduce DIVER, a method that quantifies intact virus and is robust to sample dilution. DIVER first tags viral particles with exogeneous oligonucleotides, then captures the tagged particles on ACE2-functionalized beads, and finally quantifies the oligonucleotide tags using qPCR. Using spike-presenting liposomes and Spike-pseudotyped lentivirus as SARS-CoV-2 models, we show that DIVER can detect 1×105 liposomes and 100 pfu lentivirus and can successfully identify positive samples in pooling experiments. Overall, DIVER is well-positioned for efficient sample pooling and expanded community surveillance.

Swab pooling: A new method for large-scale RT-qPCR screening of SARS-CoV-2 avoiding sample dilution

To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling of equal volumes from individually collected samples. Paired analysis of pooled and individual samples from 613 patients revealed 94 positive individuals. Having individual testing as reference, no false-positives or false-negatives were observed for swab pooling. In additional 18,922 patients screened with swab pooling (1,344 pools), mean Cq differences between individual and pool samples ranged from 0.1 (Cr.I. -0.98 to 1.17) to 2.09 (Cr.I. 1.24 to 2.94). Overall, 19,535 asymptomatic patients were screened using 4,400 RT-qPCR assays. This corresponds to an increase of 4.4 times in laboratory capacity and a reduction of 77% in required tests. Therefore, swab pooling represents a major alternative for reliable and large-scale screening of SARS-CoV-2 in low prevalence populations.

New Atomic Absorption Methods for Metals Determination in Aviation and Automotive Gasoline

New methods for direct atomic absorption determination of lead and lithium as antiknock additives components in aviation and automotive gasoline in the concentration ranges 100–1700 (Pb) and 2.5/0.25–100 (Li) mg/L have been developed. To overcome the difference in analytical signals for samples and standard solutions due to concentration values and matrix effects the proper sample dilution and the addition of the blank as pure reagent hydrocarbons mixture in the solutions have been offered. The methods have high precision, are simple and may be recommended for gasoline quality control and identification procedures.