Radioactive Gold Isotopes in the Era of Theranostics: Medical Potential of ¹⁹⁸Au and ¹⁹⁹Au Radioisotopes.

Verapamil is a calcium channel blocking drug often prescribed to treat hypertension. The increase in verapamil prescriptions has led directly to an increase in overdoses, both intentional and accidental. The aim of this study was to develop a simple, fast and sensitive HPLC method with fluorescence detection for the quantitation of verapamil and its major metabolite norverapamil in postmortem samples. This study compared liquid-liquid and solid phase (C2 silica) extraction techniques for quantitation of verapamil and norverapamil in postmortem blood, liver and kidney. The method was also applied to a blood sample collected in the emergency room from a patient suffering from a verapamil overdose. The experiment established a five-point standard curve that crossed both therapeutic and fatal concentrations of verapamil and norverapamil (100 to 3,000 ng mL−1 for blood and 100 to 3,000 ng g−1 for tissues). The standard curves were linear over the range of verapamil and norverapamil concentrations assayed and had correlation coefficients greater than 0.9784±0.0198 for both liquid-liquid and solid phase extractions. The limit of quantitation for verapamil and norverapamil in all specimens studied was established to be 100 ng mL−1 and 100 ng g−1. Intra-day variability was determined using 3–6 replicates of controls (2,500 ng mL−1 of blood or 2,500 ng g−1 of tissue homogenate) prepared in naive blood and tissues and analyzed on a single day. Inter-day variability was determined over a four day period analyzing replicates of controls. Control solutions prepared in naive blood, kidney and liver homogenates in the fatal concentration levels fell within the acceptable precision and accuracy range. Furthermore, liquid-liquid extraction is preferable to solid phase extraction for quantitation of verapamil and norverapamil in tissues because it is simpler, more versatile, more precise, more accurate and less expensive.

The effectiveness of solid phase extraction (SPE) using 90‐mm EmporeTM C‐18 bonded disks and liquid‐liquid extraction (LLE) was compared in extraction of municipal wastewater effluent, as well as distilled and sea water. Both SPE and LLE obtained similar recoveries of polycyclic aromatic hydrocarbons and polychlorinated biphenyls from spiked distilled water. Higher recoveries of chlorinated pesticides were achieved from distilled water than from wastewater effluent by SPE. In addition, SPE yielded higher concentrations of PAHs and LABs from effluent samples than did LLE. Apparently, both SPE and LLE were affected by the presence of abundant dissolved organic carbon in wastewater effluent, but LLE suffered more losses. The condensed packing structure in C‐18 disks might allow better extraction of hydrophobic organics from wastewater effluent. Alumina/silica gel clean‐up after SPE was necessary to obtain acceptable quantitation results for wastewater effluent. SPE was technically as effective as LLE and superior to LLE, because it used less organic solvent and manpower. Usage of high density glass beads with C‐18 disks further improved the efficiency of SPE. Lowering the cost of C‐18 disks will make disk SPE more appealing. © 1995 John Wiley & Sons, Inc.

To determine levels of histamine, two methods were used, photometry in conjunction with two sample clean-up procedures, and capillary zone electrophoresis (CZE). The two sample clean-up procedures used were liquid liquid extraction (LLE) with n-butanol and solid phase extraction (SPE). Using CZE, the separation of histamine from the matrix was good. The other method, photometry, represents a classic and simple method, that can be employed for in situ measurement of histamine. We found that it was necessary to clean up the samples prior to photometry; if this was not done, the recorded levels of histamine were higher than those determined by CZE. In order to determine levels of histamine, both of these rapid tests were applied to ten different foodstuffs. The levels of histamine measured using photometry following either LLE or SPE were compared. The results indicated that photometry is a suitable method for the measurement of histamine, although the sample solutions have to be purified by either LLE or SPE. Samples do not need to be cleaned up before CZE because there is no interference between histamine and attendant material. Both sample clean-up procedures were applied to the following foodstuffs: tomatoes, sauerkraut, tuna, leaf spinach, cream spinach, white wine and mackerel. The differences of the measured values vary between 3% and 18% for LLE and 6% and 27% for SPE. For the other foodstuffs, such as beef, beer and non-alcoholic beer, only one sample clean-up procedure is suitable. LLE used for beef and beer leads to differences in measured levels of histamine between 18% and 50%, respectively, whereas SPE used for non-alcoholic beer leads to differences of 20%.

Solvent usage and extraction times can be reduced significantly by solid phase extraction (SPE) over liquid/ liquid extraction (LLE). This research adapts existing SPE membrane disk methods to allow for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlo rinated dibenzofurans (PCDFs) in industrial effluent and surface water samples containing particulate matter. When several types of filtering media are lagered on top of the membrane disk, particulate matter and suspended solids in an effluent sample can be prevented from plugging the disk, allowing an entire sample to be extracted without the need for prefiltering. PCDDs and PCDFs can then be eluted directly from the filtering medium and disk. For 29 effluent samples with particulate matter, the mean values of the internal quantitation standard recovery ranged from 58 to 70% for LLE and from 65 to 77% for SPE. The average recovery was 8% higher for the SPE method over the LLE. Studies in this laboratory have shown that SPE membranes can replace LLE for essentially any aqueous sample. Extensive comparisons of LLE and SPE indicated that these two methods are equivalent statistically. In addition, SPE is quicker and less labor intensive than LLE

An experimental approach for pesticide mobility studies in the soil environment has been developed, based on three main aspects: 1) the development of analytical procedures suitable for unsaturated zone pesticide monitoring; 2) adsorption studies; 3) controlled application of pesticides to two experimental sites and subsequent analysis of soil and water samples. Four pesticides have been selected to perform this study: two herbicides (atrazine and metribuzin) and two organophosphorus insecticides (fenamiphos and chlorpyrifos). Soil and water samples spiked at different levels with pesticides were used to validate the analytical procedures by obtaining recoveries and coefficients of variation. Extraction procedures for water samples included: liquid-liquid extraction (conventional and micro scale) and solid phase extraction using C18 cartridges and elution with ethyl acetate. Detection limits for water sample extraction using either liquid-liquid extraction or solid phase extraction were similar and ranged between 0.02 and 0.3 μg 1−1, while for the liquid-liquid microextraction minimum detectable concentration was in the range of 1–10 μg 1−1, Extraction of soil samples was carried out with acetone, followed by two different clean-up procedures based on liquid-liquid partition and solid phase extraction with C18 cartridges (detection limits between 0.3 and 0.6 ng g−1). Results obtained for adsorption studies predicted that atrazine and metribuzin were probable leachers while the organophosphorus pesticides studied should be considered as improbable leachers. This agreed completely with the mobility results obtained in experimental plot experiments.

One of the key steps in chemical analysis is sample preparation. It is a very important step prior to analysis, otherwise the analyte signal could be suppressed by sample matrix interference. In most cases sample preparation entails some form of extraction of the analyte(s) of interest from the interfering species. Conventional extraction techniques include liquid-liquid extraction (LLE) and solid phase extraction (SPE). LLE involves mixing two immiscible solvent together, and based on solubility equilibria the analyte or the interfering species partitions preferentially in the organic solvent. Ideally, the partition coefficient is very high to allow for efficient extraction (Park et al., 2001). In SPE, analytes of interest are extracted from solution by passing the liquid through a solid phase, such as a C18 SPE cartridge. Based on different physical and chemical properties, the desired solute either is adsorbed onto the solid phase, from whence it can later be eluted, or remains in solution while impurities are retained on the solid phase (Korner et al., 2000). The LLE and SPE extraction methods are laborious and demand the use of copious amounts of samples and solvents, therefore driving up the cost of chemical analysis. For LLE, emulsion formation can be a nuisance. These methods are also limited by factors like cartridge clogging in SPE, single use of the SPE and the need for toxic and polluting solvents (such as halogenated solvents like chloroform and dichloromethane) in LLE.

Purpose: This investigation was initiated to determine the absorbed dose and radioactivity distribution of radioactive gold nanoparticles.Methods: Polymer gel dosimeter was prepared using about 12% gelatin (Sigma Aldrich, 300 bloom type A), 9% methacrylic acid(Sigma Aldrich), 10mM THPC (Sigma Aldrich), 18mM hydroquinone (Sigma Aldrich) in deionized water. These dosimeters are used for calibration purpose and meant to estimate the absorbed dose in the medium from the radiation emitted by the radioactive gold nanoparticles. The high energy gamma dose, activity distribution were measured using SPECT imaging and the phantom used was the ball of play‐doh made by Hasbro Toys. A previously constructed acrylic cast of beagle dogˈs head was used in this study to place the phantom. The radioactive gold nanoparticles were synthesized at the University owned nuclear reactor with the high neutron flux of ∼10e14 neutrons/cm2/sec.Results: Carbohydrate suspended radioactive nanoparticles with approximately 200 microCuries were injected in a play doh ball, depicting the prostate gland of beagle dog, approximately 1 inch diameter (8–10ml) in size. The phantom was placed on the SPECT imaging table near the isocenter of the imaging plane. The Gamma camera was peaked for the 411keV photon and equipped with a high energy (Iodine collimator). The phantom was then imaged using SPECT imaging protocol. The activity imaged at various planes and count rates was evenly distributed as predicted Conclusions: The activity distribution as seen in the SPECT imaging indicated active hot and cold spots of radioactive gold nanoparticles. The use of play‐doh determines the activity distribution but uneven diffusion. To compensate for that polymer gel dosimeters, equivalent to the tissue densities may be considered, besides there is also an advantage of estimating the absorbed doses.

Rosmarinus officinalis leaves (ROLs) are widely used in the food and cosmetics industries due to their high antioxidant activity and fascinating flavor properties. Carnosic acid (CA) and rosmarinic acid (RA) are regarded as the characteristic antioxidant components of ROLs, and the selective separation of CA and RA remains a significant challenge. In this work, the feasibility of achieving the selective separation of CA and RA from ROLs by solid-phase extraction (SPE) and liquid–liquid extraction (LLE) was studied and compared. The experiments suggested that SPE with CAD-40 macroporous resin as the adsorbent was a good choice for selectively isolating CA from the extracts of ROLs and could produce raw CA with purity levels as high as 76.5%. The LLE with ethyl acetate (EA) as the extraction solvent was more suitable for extracting RA from the diluted extracts of ROLs and could produce raw RA with a purity level of 56.3%. Compared with the reported column chromatography and LLE techniques, the developed SPE–LLE method not only exhibited higher extraction efficiency for CA and RA, but can also produce CA and RA with higher purity.

Amaç: Günümüzde kötüye kullanılan yasadışı maddeler arasında en yaygın kullanılan madde esrardır. Esrarın saptanmasına yönelik yapılan çalışmalarda, idrarda ana metaboliti olan THC-COOH’un kat-faz (SPE) ve sıvı-faz (ELE) ekstraksiyon teknikleri ile analizi yer almaktadır. Bu çalışmanın amacı, sentetik idrar örneklerinde THC-COOH analizi için GC-MS ile tayini öncesinde SPE ve LLE metodlarını kullanarak örnekleri analize hazırlamak ve bu yöntemlerin örnek hazırlamadaki verimleri ve etkinlikleri karşılaştırmaktır. Aynı zamanda bu yöntemlerin tekrarlanabilirlik, seçimlilik, doğruluk, kesinlik ve doğrusallık gibi validasyon parametreleri inceleyerek yöntem geçerliliğini değerlendirmektir.Gereç ve Yöntem: Ana standart olarak (±)-ll-nor-9-carboxy-A9-THC ve iç standart olarak (±)-ll-nor-9-carboxy-A9-THC-D3 kullanılmıştır. LLE için Toxi-tube B, SPE için Clean Screen THC kartuşları kullanılmıştır. Türevlendirme için BSTFA+%1 TMCS kullanılmıştır. Analizler Thermo Finnigan Trace Gaz Kromatografisi-Kütle Spektrometrisi (GC-MS) cihazı ile yapılmıştır. SPE ve LLE metodlarının karşılaştrılması Minitabll istatistik paket programı ile yapılmıştır.Bulgular: Çalışmamızda en düşük tayin sınırı olarak (LOD) 2 pg/L elde edilmiştir. Elde edilen sonuçlarda geri kazanım değerleri %90’nın üzerinde ve %RSD değerleri %10’nun altında bulunmuştur. 25-500 pg/L arasındaki konsantrasyonlarda kantitatif tayin yapılabilmesi için gerekli olan doğrusallığın var olduğu tespit edilmiştir. Uygulanan Anderson-Darling testi ile LLE ve SPE sonuçlarının normal bir dağılıma uymadığı görüldüğünden non-parametrik test olan Wilcoxon signed-rank testi uygulanmıştır.Sonuç: Çalışmamızda bulunan doğrusallık, tekrarlanabilirlik ve geri kazanılabilirlik değerleri, biyoanalitik validasyon kriterleri doğrultusunda kabul edilebilir düzeyde bulunmuştur. Elde edilen istatiksel sonuçlara göre, LLE ve SPE metodları arasında istatistiksel olarak anlamlı bir fark bulunmuştur (p<0.005). Yapılan çalışma ile analiz öncesinde örnekhazırlamabasamağının önemi gösterilmiştir.Anahtar Kelimeler: TCH_COOH, Sıvı-Sıvı Ekstraksiyon, Katı Faz Ekstraksiyon, İdrar, Gaz Kromatografi Kütle Spektrometri.

BACKGROUNDOxytocin (OT) needs to be measured accurately to research its associations with social behaviors, conditions, and diseases in humans. Available enzyme‐linked immunosorbent assays lack the sensitivity to measure the very low (pg/mL) circulating levels in non‐pregnant/‐lactating humans (NPLH) reliably while radioimmunoassays are accurate but involve hazardous radioactive materials. One‐dimensional liquid chromatography mass spectrometry (LCMS) methods are currently not sensitive enough. Our recently developed LCMS method (Franke, 2018 PMID 30091853) can quantitate serum OT down to 10 pg/mL but precludes quantification in NPLH, which is known to be < 5 pg/mL. Thus, we sought to improve the lower limits of detection (LLOD) of OT measurements by forming OT products with higher lipophilicity thereby increasing the MS sensitivity as well as achieving better liquid‐liquid extraction (LLE) or solid‐phase extraction (SPE) outcomes.METHODS200 uL aq. OT (0.01–10 ng/mL) was reduced using 1,4‐dithiothreitol(DTT) or tris(2‐carboxyethyl)phosphine (TCEP) to cleave the dithio ether followed by alkylation with N‐alkyl iodoacetamide using alkyl chains (C10 to C18) according to Williams et al. 2009 (PMID 19734056). A second strategy involved derivatization of the phenolic tyrosine hydroxyl with biphenyl sulfonyl or dansyl chloride. The resulting products were then concentrated using LLE or SPE.RESULTSReduction using DTT or TCEP resulted in >95% cleavage to OT‐dithiol. Subsequent alkylation products derived from N‐alkyl iodoacetamide alkyl chains C10 and C12 were chosen over those with C14 or C16 for further analysis due to better product sensitivity. However, these products produced low yields and lower LCMS sensitivity than the underivatized OT. Enriching these products by LLE or SPE were also unsuccessful. Derivatization using biphenyl sulfonyl or dansyl chloride yielded mono‐tagged adducts of the reduced and unreduced OT but had lower LCMS sensitivity than the underivatized OT. Enriching these adducts with LLE or SPE did not improve LLOD via concentration.DISCUSSIONAlkylation of the thiol groups of the reduced OT with N‐alkyl iodoacetamide or sulfonylation of native OT with an array of sulfonyl chlorides led to products less sensitive than underivatized OT. Attempts for enrichment of these products by SPE and LLE were unsuccessful.CONCLUSIONImproving LCMS LLODs of OT by derivatization approaches were unsuccessful as was enrichment of these products by LLE or SPE. Current attempts to enrich native OT from human serum for the improvements of LLOD during LCMS analyses are presented.Support or Funding InformationNoneThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Nuclear conversion of 195AuFe into 195PtFe centers in silicon: observations by magnetic resonance

ABSTRACT: A gas chromatographic-mass spectrometric (GC-MS) method was developed for detection of fluoxetine and its active metabolite norfluoxetine in urine. Liquid and solid phase extraction were applied to urine samples using maprotiline as an internal standard (IS). The GC-MS analysis were carried out using HP-5MS capillary column. The linearity ranges of the method were 5-75 ng mL-1 for fluoxetine and 6-125 ng mL-1 for norfluoxetine by solid phase extraction (SPE), and 10-80 ng mL-1 for fluoxetine and also norfluoxetine by liquid- liquid extraction (LLE). Also the range of detection limits were between 1-10 ng mL-1, the range of quantification limits were between 5-10 ng mL-1 for fluoxetine and norfluoxetine by both SPE and LLE. The range of recoveries were between 87 -109 % by both SPE and LLE for analytes. The developed method allowed clinical and toxicological analysis of fluoxetine and norfluoxetine in urine samples. KEY WORDS: Fluoxetine; Norfluoxetine; Gas Chromatography-Mass Spectrometry; Liquid- Liquid Extraction; Solid-Phase Extraction.

The extraction of drugs from biological matrices is an essential specimen preparation step in current forensic postmortem laboratories. Traditionally, liquid/liquid extractions (LLE) were developed and employed to screen for the general unknown. However, solid-phase extractions (SPE) are becoming more popular as the availability of columns with suitable stationary phases increased. The purpose of this work was to determine if switching from an existing LLE to SPE was feasible. The limits of detection (LOD) for 122 drugs and metabolites were determined in blood following SPE and compared to previously determined LOD's by LLE, if available. There were 41 drugs that had LOD's in blood established by both methods; LLE had a lower LOD for 8 drugs (19.5%), SPE had a lower LOD for 16 (39%), and the LOD's were comparable in the remaining drugs. Although SPE cartridges were more expensive than LLE, SPE was determined to be a faster technique and doubled the number of specimens that could be extracted by one analyst within a specific timeframe. The SPE method utilized enabled the detection of several drugs not detectable after LLE (most notably, morphine and benzoylecgonine) and allowed the extraction of weakly acidic and neutral drugs with only one extra step.

Refining wastewater-based epidemiology for cannabis consumption monitoring: Relevance of analysing both the aqueous phase and suspended solids of influent wastewater

Quantification of fullerene aggregate nC 60 in wastewater by high-performance liquid chromatography with UV–vis spectroscopic and mass spectrometric detection