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was carried out on a 250 × 4.6-mm, 5-μm column (Diamonsil C18; Dikma Technologies, Foothill Ranch, CA). Detection was operated at 214-nm wavelength with 0.1 mmol·L −1 KH 2 PO 4 (pH = 2.6) as mobile phase passed through a 0.45-μm membrane filter. The

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(pH 2.0, using 6 M HCl). With a separatory funnel, the free phenolic compounds were extracted with diethyl ether (5 × 20-mL portions). The extractant was composed of acetone, water, and acetic acid. The organic phase (acetone) was removed using the

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remaining pellet was again resuspended in 40 mL of HCl, pH 2.5, and incubated for 90 min at 60 °C. The extract was centrifuged and filtered to obtain the acid-soluble pectin (ASP). The remaining pellet was resuspended in 40 mL of 0.05 m NaOH and incubated

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) with an automated titrimeter and electrode standardized to pH 2.0, 4.0, 7.0, and 10.0 buffers. Titratable acidity was determined using 6 g of juice diluted with 50 mL of deionized, degassed water by titration of 0.1 N sodium hydroxide to an endpoint of

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Detector set at 210 nm using an X-bridge C18 column (4.6 × 250 mm, 5 μm, Waters Corporation) operated at 30 °C. The elution solvent was 0.01 mol·L −1 sulfuric acid (pH 2.6) passed at a rate of 0.5 mL·min −1 . The quantity and type of organic acids were

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  =   0.8780   ×   Δ pH 3 +   1.3369   ×   Δ pH 2 +   9.9856   ×   Δ pH −   0.2569 [1] Plant growth was measured as root and shoot dry weight gain during the experiment. Root and shoot tissue from seedlings and from final replicates was oven-dried for 48 h

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pH using a pH meter (Model 215; Denver Instrument, Bohemia, NY). We extracted P, K, Ca, Mg, Na, and S using the Mehlich III extractant (a dilute acid-fluoride-EDTA solution of pH 2.5 that consists of 0.2 N CH 3 -COOH, 0.25 N NH 4 NO 3 , 0.015 N NH 4 F

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of 5 m m potassium phosphate monobasic (KH 2 PO 4 ), pH 2.65, with 0.1% of formic acid (solution A) and methanol with 0.1% of formic acid (solution B). The linear gradient of the mobile phase was programmed as follows: 5% to 15% B for 1 min, followed

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. The chromatographic column (3 μm, 150 × 3 mm) was an Acclaim 120 C18 (Dionex, Sunnyvale, CA), and the column temperature was 30 °C. Mobile phase A was acetonitrile, mobile phase B was water (adjusted to pH 2.6 with acetic acid), and the flow rate was 0

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a BEH C18 column (Aquity, Waters Co). Each well was injected in triplicate with 5 μL of sample volume. The mobile phases consisted of 5 m m potassium phosphate monobasic (KH 2 PO 4 ), pH 2.65, with 0.1% of formic acid (mobile phase A) and methanol

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