scholarly journals Fluorometric method based on molecular recognition solid-phase extraction for determination of riboflavin in milk and infant formula

2016 ◽  
Vol 45 ◽  
pp. 141-146 ◽  
Author(s):  
Marcelo V. Osório ◽  
Sara S. Marques ◽  
Hugo M. Oliveira ◽  
Luisa Barreiros ◽  
Marcela A. Segundo
Keyword(s):  
Molecular Recognition ◽  
Solid Phase Extraction ◽  
Infant Formula ◽  
Solid Phase ◽  
Phase Extraction ◽  
Fluorometric Method

Determination of free nucleotides in infant formula by solid phase extraction-liquid chromatography

2019 ◽  
Vol 37 (12) ◽  
pp. 1349
Author(s):  
Lili YIN ◽  
Shan LI ◽  
Chuanjing ZHOU ◽  
Zhi CHENG ◽  
Hong ZHENG ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Infant Formula ◽  
Solid Phase ◽  
Phase Extraction ◽  
Free Nucleotides ◽  
Extraction Liquid

scholarly journals Determination of lead in solution by solid phase extraction, elution, and spectrophotometric detection using 4-(2-pyridylazo)-resorcinol

2013 ◽  
Vol 11 (5) ◽  
pp. 672-678 ◽  
Author(s):  
Ismail Rahman ◽  
Yoshiaki Furusho ◽  
Zinnat Begum ◽  
Rika Sato ◽  
Hiroshi Okumura ◽  
...  
Keyword(s):  
Detection Limit ◽  
Molecular Recognition ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Linear Range ◽  
Phase Extraction ◽  
Spectrophotometric Detection ◽  
Molecular Recognition Technology ◽  
Complex Ion

AbstractLead (+2) was selectively adsorbed on a solid phase extraction (SPE) gel (molecular recognition technology, MRT), quantitatively extracted, and spectrophotometrically determined as the Pb(II)-PAR (4-(2-pyridylazo)-resorcinol) complex. The linear range was 0.01 to 0.75 mg L−1 and the detection limit was 6.4 µg L−1. The MRT-SPE allows selective Pb(II) extraction from complex ion-rich matrices, which is difficult with other techniques. Interference from common matrix ions such as Fe2+, Ni2+, Cu2+ or Co2+ is minimized.

scholarly journals Determination of Niacin in Infant Formula by Solid-Phase Extraction and Anion-Exchange Liquid Chromatography

2001 ◽  
Vol 84 (3) ◽  
pp. 789-804 ◽  
Author(s):  
Denis E LaCroix ◽  
Wayne R Wolf ◽  
Eural Porter ◽  
Dennis Cantellops ◽  
G William Chase ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Anion Exchange ◽  
Infant Formula ◽  
Sodium Acetate ◽  
Solid Phase ◽  
Phase Extraction ◽  
Acetic Acid Buffer

Abstract A peer-verified, solid-phase extraction (SPE)/anion exchange liquid chromatographic method is presented for the determination of niacin in milk-based and soy-based infant formula. Analysis is in 3 steps: test sample digestion, extraction/cleanup, and liquid chromatography (LC). Digestion uses a standard AOAC digestion procedure that involves autoclaving at 121°C for 45 min in (1 + 1) H2SO4 to free endogenous niacin from protein and to convert added niacinamide to niacin. The digest solution is adjusted to pH 6.5 with 7.5M NaOH. Acidification to pH <1.0 with (1 + 1) H2SO4 precipitates the protein. The clarified solution is then filtered, and the filtrate is brought to volume. SPE of niacin is accomplished by passing an aliquot of the digest solution through an aromatic sulfonic acid–SPE (ArSCX–SPE) column. After the column is washed with methanol and water to remove extraneous material, the niacin is eluted with 0.25M sodium acetate/acetic acid buffer at pH 5.6. An anion-exchange polystyrene–divinylbenzene column with 0.1M sodium acetate/acetic acid buffer at pH 4.0 is used for LC. Niacin is determined by UV detection at 260 nm. A standard curve is prepared by passing known amounts of niacin through the ArSCX–SPE columns used for niacin extraction. The following values for x_bar and relative standard deviation (RSD) were obtained for National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1846 Infant Formula with a certified value for niacin of 63.3 ± 7.6 μg/g: Submitting laboratory.— x_bar = 59.7 ± 4.0 μg/g; RSD = >6.7%; confidence interval (CI) = ± 1.4 μg/g; n = 27. Peer laboratory.— x_bar = 56.6 ± 6.6 μg/g; RSD = >11.7%; CI = ± 4.1 μg/g; n = 8.

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