University of North Florida
Browse the Citations
-OR-

Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

View Stuart Chalk's profile on LinkedIn

Organic compound

Classification: Organic compound -> gelatin

Citations 4

"Automated Flow Injection Measurement Of Photographic Dyes In Gelatin At Elevated Temperatures"
Analyst 1990 Volume 115, Issue 11 Pages 1407-1410
Richard H. Taylor, Gregory D. Clark, Jaromir Ruzicka and Gary D. Christian

Abstract: Photographic dyes in a gelatin matrix were determined by automated flow injection analysis, by using the split zone - gradient chamber dilution technique (Clark et al., Anal. Chem., 1989, 61, 1773), DMSO as carrier solvent and direct spectrophotometric detection (at 553 nm for a magenta dye and 459 nm for a yellow dye). The matrix was kept liquid by placing the apparatus in an incubator oven at 41°C to 44°C. With dilution times of 60 and 30 s for the magenta and yellow dyes, respectively, calibration graphs were rectilinear for 60 and 100 g l-1, respectively. The coefficient of variation was 2% for dilutions of 2000-fold. Results agreed to within 5% with those of a manual method.
Dyes, photographic Spectrophotometry Automation Heated reaction Dilution Apparatus Calibration Mixing chamber

"Flow Injection Spectrophotometric Determination Of Aspartame In Dietary Products"
Analyst 1994 Volume 119, Issue 9 Pages 2101-2104
Joaquim de Araújo Nóbrega, Orlando Fatibello-Filho and Iolanda da Cruz Vieira

Abstract: A flow injection spectrophotometric method has been developed for the determination of aspartame in dietary products using ninhydrin as a colorimetric reagent. The reaction was conducted in a 1 + 1 v/v methanol-isopropanol medium also containing potassium hydroxide. The absorbance measurements were made at 603 nm. The results obtained for the determination of aspartame in table sweetener, pudding, gelatin, and refreshment (i.e., a powder dissolved in water for drinking) are in good agreement with the results obtained using a conventional manual procedure (correlation coefficient, r = 0.9984). Thirty-six results were obtained per hour, and the relative standard deviation was less than 3.5% (n = 6) for all samples. The detection limit (three times the signal blank/slope) was 3.8 x 10^-5 mol L-1 of aspartame. Sample (0.2-0.6 g) was stirred with 10 mL of methanol/propan-2-ol (1:1; solvent A) for 2 min. The suspension was filtered and the filtrate was diluted to 25 mL with solvent A. A portion of the solution was injected into a carrier stream (2.5 ml/min) of solvent A and subsequently merged with streams (both 0.3 ml/min) of 0.293 M KOH and 0.037 M ninhydrin (both in solvent A). The mixture was transported to a helical reaction coil (2 m x 0.8 mm i.d.) immersed in a water-bath kept at 60°C. The solution then passed through a de-bubbler after which the absorbance was measured at 603 nm. A diagram of the manifold used is given. The calibration graph was linear from 0.34-2.4 mM aspartame, the detection limit was 38 µM and the RSD (n = 6) was 3.5%. Recoveries were quantitative and the throughput was 36 samples/h. The method was applied to several dietary products, viz., table sweetener, pudding, gelatin and refreshment powder.
Aspartame Spectrophotometry Heated reaction

"Determination Of Trace Iron And Copper In Gelatin By Flame Atomic Absorption Spectrophotometry With A Flow Injection Extraction System"
Guangpuxue Yu Guangpu Fenxi 1995 Volume 15, Issue 4 Pages 85-90
Chen, S.Y.;Zhang, M.;Lin, S.Q.;Cheng, L.

Abstract: Sample (1.2 g) was soaked in 20 mL water for 15 min and the swollen sample was hydrolyzed with 1 mL HCl and 1 mL HNO3 at 130°C for 2 h. The hydrolysate was treated with 1 mL H2O2 and hydrolyzed at high temperature for 20 min. After removing H2O2, the hydrolysate was adjusted to pH 3.6 and diluted to 25 mL with water. Portions (900 µL) of the solution were injected into a stream of 1% sodium diethyldithiocarbamate solution in 0.3 M acetic acid/sodium acetate buffer containing MIBK as extractant of a flow injection system (diagram given) for online extraction. Calibration graphs were linear up to 1.4 and 0.25 µg/ml, respectively, for Fe and Cu and the corresponding recoveries were 90.8-110.5 and 87.5-107%. RSD (n = 12) were 4.53 and 4.26%, respectively for 0.2 and 0.08 µg/ml of Fe and Cu, respectively.
Copper Iron Spectrophotometry Sample preparation Extraction MIBK

"FAAS Determination Of Calcium And Magnesium In Gelatin Using The FIA Online Automatic Dilution Technique"
Lihua Jianyan, Huaxue Fence 1996 Volume 32, Issue 2 Pages 82-91
Zhang Min, Chen Shuyu, Lin Shuqin and Cheng Lin

Abstract: Sample (1.2 g) was soaked in 15 mL water for 15 min and digested with 1 mL concentrated HCl, 1 mL concentrated HNO3 and 4 mL H2O2. The digest was diluted with to 25 mL with water for FIA with flame AAS detection of Ca and Mg. Test solution was injected and carried to two sampling loops with a stream of water for alternating feeding, primary and secondary injection volumes being 21 and 70 µL, respectively. The solution was allowed to mix with a stream of 0.3% La solution prior to splitting into two streams by passing through two dilution tubes of 50 and 150 cm in length, respectively, with dilution of 87 to 233-fold, and detection. The peak B of the sets of signals was employed for measurement of Ca whereas the trough E for Mg. Determination was at µg/g level. RSD were 1.3-2.1%. The method was applied to the analysis of wheat, shrimp, pig liver and shrub leaves. Interference from phosphate was overcome. Sampling frequency was 96 runs/h.
Calcium Magnesium Sample preparation Spectrophotometry Interferences Dual injector Sample splitting