Analysis of Nicotine and Nicotine-Related Compounds in Electronic Cigarette Liquids and Aerosols by Liquid Chromatography-Tandem Mass Spectrometry

Summary The objective of this study was to develop and validate an analytical method for determining nicotine and nicotine related compounds (i.e., nicotine-N-oxide, cotinine, nornicotine, anatabine, myosmine, anabasine, and β-nicotyrine) in e-cigarette aerosols and e-liquids. Aerosol collection was achieved using a Cambridge collection pad. The sample preparation consisted of adding deuterated internal standards to the collection pad and extracting with 100 mM ammonium acetate solution using a wrist-action shaker. The filtrate was then analyzed by LC-MS/MS using a Gemini NX C18 column (3 μm, 150 × 3 mm) with a mobile phase gradient system consisting of acetonitrile and 10% acetonitrile in 10 mM ammonium bicarbonate (pH = 8.0) and electrospray ionization (ESI) in the positive mode. The e-liquid was analyzed using the same instrumental parameters, but simplifying the sample preparation procedure by adding deuterated internal standards directly to the 100-mg sample. The sample was then extracted with 100 mM ammonium acetate solution, sonicated, and filtered. In this study, the method’s accuracy, robustness, and reliability were enhanced by using deuterated analogues of each compound as internal standards and by applying two ion-transition pairs for each compound for the confirmation and quantification. Validation experiments demonstrated good sensitivity, specificity and reproducibility. All the target compound calibrations exhibited satisfactory linearity from 0.050 to 5.0 mg/mL (r2 > 0.995). The average recoveries for e-liquids varied from 85.2% (nicotine-N-oxide) to 110% (β-nicotyrine) with recoveries for all compounds exhibiting a coefficient of variation (CV) < 5.0%. Similarly, the average recoveries for e-cigarette aerosols varied from 87.8% (for nicotine-N-oxide) to 111% (for myosmine) with all CV < 8.8%. The LOD and LOQ for e-liquids for all target compounds ranged from 0.234 and 0.781 μg/g (cotinine) to 1.66 and 5.48 μg/g (nicotine-Noxide). For e-cigarette aerosols these limits ranged from 0.094 and 0.312 μg/collection (cotinine) to 0.872 and 2.87 μg/collection (nicotine-N-oxide). This methodology was used to quantitatively determine if any of the target compounds were present in a variety of sample matrices, including e-cigarette solutions and aerosols, and was successfully applied to stability studies, to monitor changes in the target compound levels which might be caused by e-cigarette formulations, components and the storage conditions.

Blueberry, Full Season Control of Broad Spectrum Insect Pests, 1994

Insecticides were applied to mature blueberry bushes near Douglas, MI at a rate of 50 gpa with a FMC 1029 airblast sprayer. Treatments were arranged in a completely randomized design of single 44 foot-long rows of vines replicated 4 times. Funginex was applied separately to all treatments. Applications of materials were made on 16 Jun (Petal Fall), 22 Jun (PF), 21 Jul (BBM threshold) and 2 Aug (BBM threshold + 14 days). Maggot threshold was defined as the capture of 2 adult R. mendax flies in yellow sticky card traps sprayed with a saturated ammonium acetate solution. The first maggot spray was applied within 7 days of reaching the threshold. Damage from early season fruitworms was evaluated on 13 Jun. Damage was assessed by sampling 50 fruit clusters from each replicate. Each cluster was rated for the presence or absence of fruitworm injury. BBM injury was evaluated on 16 Aug. Maggot injury was assessed by picking 2 onepint subsamples of fruit from each replicate. Subsamples were processed by macerating one pint of berries and 2 cups of water in a blender. The solution was then poured through a series of sieves. Maggots were retained on the finest sieve. Results were expressed as maggots per pint of berries.

The effect of permeant and impermeant osmoticants on exocytosis in guinea pig sperm

Guinea pig sperm were suspended in calcium-containing medium supplemented with various concentrations of the tetrasaccharide, stachyose. At concentrations up to and including 0.6 M, stachyose was without effect on the A23187-induced acrosome reaction. At 1.0 M stachyose, greater than 97% of sperm retained their acrosome after exposure to A23187, as judged by light microscopy. Electron microscopy demonstrated, however, that exocytotic membrane fusion had occurred, although with substantial retention of the acrosomal matrix. Sperm incubated in 1.0 M stachyose solutions also underwent exocytotic membrane fusion in the absence of A23187 and external calcium. Sperm suspended in 0.175 M ammonium chloride solution progressively lost motility over 30 min, but without acrosomal swelling. By contrast, sperm in 0.19 M ammonium acetate underwent substantial swelling of the acrosome within 2–5 min. 70–80% of these sperm were able to exclude the vital dye propidium iodide with their acrosomes swollen. These sperm underwent acrosomal shrinkage if resuspended in normal medium within 5–10 min, and the majority (60–70%) recovered some motility. These sperm could undergo an A23187-induced acrosome reaction. Electron microscopy indicated that swelling in ammonium acetate solution solubilizes much of the acrosomal matrix and causes internal fusion between adjacent regions of the outer acrosomal membrane. There was no exocytotic membrane fusion in ammonium acetate solution, however. The evidence suggests that there is no stachyose osmolality for guinea pig sperm which will suppress the membrane fusion associated with exocytosis, and that sufficiently high osmolalities cause exocytotic membrane fusion in the absence of calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

A Simple Way to Make 113mIn-Fe(OH)3 Particles

SummaryUsing a buffer system, a method of preparing sterile and pyrogen-free 113mIn-labeled Fe(OH)3 macroaggregates has been developed which is simpler, more rapid and more reliable than those already reported. As buffer, an ammonium acetate solution with a pH of 9.8 ± 0.2 is used. This solution can be made sterile by Millipore filtration.The particles are prepared by mixing the reagents: eluent from generator, FeCl3 solution and buffer solution. After heating for 20 to 30 seconds in a boiling water bath a solution of gelatin is added. The time of preparation is two to three minutes.Over 1000 patients have been studied using this preparation. No side effects were observed.

Aluminium, extractable from soil samples by the acid ammonium acetate soil-testing method

The extractant, 0.5 M acetic acid –0.5 M ammonium acetate at pH 4.65, which is used in soil-testing, extracts relatively high amounts of aluminium from acid soils. The mean values of acetate-extractable aluminium at pH 4.65, 1.75 meq Al/100 g of soil, and of exchangeable aluminium (M KCI extraction), 0.41 meq Al were obtained from a material of 30 samples of acid soils (Table 2). Several other acetic acid ammonium acetate extractants, from M acetic acid to M ammonium acetate solution were also used for studying the extractability of soil aluminium. The soil-testing extractant can be used for the estimation of the soluble amounts of aluminium in acid soils, however, further studies are needed for a better interpretation of the ammonium acetate extractable (at pH 4.65) aluminium in our soils.