scholarly journals Multiresidue Analytical Method of Pesticides by GC-MS: Application of Macroporous Diatomaceous Earth Column and Silica Gel Cartridge

1997 ◽  
Vol 22 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Kazuaki IIJIMA ◽  
Machiko SAKA ◽  
Yoshitsugu ODANAKA ◽  
Osami MATANO
Keyword(s):  
Silica Gel ◽  
Analytical Method ◽  
Diatomaceous Earth

Determination of Benzo (a) pyrene in Foods

1978 ◽  
Vol 61 (1) ◽  
pp. 129-135
Author(s):  
Yukio Saito ◽  
Hiroshi Sekita ◽  
Mitsuharu Takeda ◽  
Mitsuru Uchiyama
Keyword(s):  
Sulfuric Acid ◽  
Silica Gel ◽  
Column Chromatography ◽  
Analytical Method ◽  
Selective Extraction ◽  
Acid Extraction ◽  
Simple Method ◽  
Extraction Step ◽  
Concentrated Sulfuric Acid

Abstract An analytical method was developed for determining benzo (a) pyrene in foods, suitable for routine use. The method consists of 4 cleanup steps: (1) alkali cleavage of sample, (2) preliminary silica gel column chromatography, (3) selective extraction with concentrated sulfuric acid, and (4) further silica gel column chromatography. Recoveries of benzo- (a) pyrene added to 50 g (or 10 g) food at levels of 0.4 ppb (or 2 ppb) ranged from 70% for short-necked clam and mackerel to 85% for chicken meat. The sulfuric acid extraction step affords a simple method for isolating benzo (a)- pyrene from various kinds of interfering substances which could not be separated by existing methods.

Liquid Chromatographic Determination of Polycyclic Aromatic Hydrocarbons in Fish and Shellfish

1985 ◽  
Vol 68 (5) ◽  
pp. 945-949
Author(s):  
Keigo Takatsuki ◽  
Shigeru Suzuki ◽  
Nobutoshi Sato ◽  
Isamu Ushizawa
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Silica Gel ◽  
Aromatic Hydrocarbons ◽  
Ethyl Ether ◽  
Analytical Method ◽  
Alkaline Digestion ◽  
Polycyclic Aromatic ◽  
Liquid Chromatographic ◽  
Fish And Shellfish

Abstract A simple and accurate analytical method for determination of polycyclic aromatic hydrocarbons (PAHs) in fish and shellfish is presented, which is considered to be useful for routine analyses and for screening purposes. The procedure involves alkaline digestion, extraction with n-hexane, silica gel column chromatography, and liquid chromatographic (LC) determination with fluorometric detection. During development of the analytical method for determination of PAHs, it was found that benzo[a]pyrene, a representative PAH, was decomposed easily by the analytical procedure, and this tendency was investigated for the experimental conditions used. Benzo[a]pyrene was decomposed by the coexistence of alkaline conditions, light, and oxygen; by peroxides in aged ethyl ether; and by oxygen when adsorbed on silica gel. Thus, to obtain good recoveries and precise analytical results, these decomposition conditions must be avoided. The following precautions are recommended: protection from light through all analytical steps; addition of Na2S to alkaline digestion mixture as an antioxidant; complete removal of peroxides from ethyl ether just before use; quick column chromatography on silica gel; and prevention of air from contact with adsorbent. When this simple method was applied to fish and shellfish samples, very good recoveries of PAHs from fortified fish samples were obtained, and no serious interferences were observed in fish and shellfish extracts

scholarly journals Sampling and Analytical Method for Alpha-Dicarbonyl Flavoring Compounds via Derivatization witho-Phenylenediamine and Analysis Using GC-NPD

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Stephanie M. Pendergrass ◽  
Jeffrey A. Cooper
Keyword(s):  
Gas Chromatography ◽  
Silica Gel ◽  
Analytical Method ◽  
Storage Stability ◽  
Sampling Rate ◽  
Time Sampling ◽  
Stability Studies ◽  
Sample Storage ◽  
Limits Of Detection ◽  
Quinoxaline Derivatives

A novel methodology is described for the sampling and analysis of diacetyl, 2,3-pentanedione, 2,3-hexanedione, and 2,3-heptanedione. These analytes were collected ono-phenylenediamine-treated silica gel tubes and quantitatively recovered as the corresponding quinoxaline derivatives. After derivatization, the sorbent was desorbed in 3 mL of ethanol solvent and analyzed using gas chromatography/nitrogen-phosphorous detection (GC/NPD). The limits of detection (LOD) achieved for each analyte were determined to be in the range of 5–10 nanograms/sample. Evaluation of the on-tube derivatization procedure indicated that it is unaffected by humidities ranging from 20% to 80% and that the derivatization procedure was quantitative for analyte concentrations ranging from 0.1 μg to approximately 500 μg per sample. Storage stability studies indicated that the derivatives were stable for 30 days when stored at both ambient and refrigerated temperatures. Additional studies showed that the quinoxaline derivatives were quantitatively recovered when sampling up to a total volume of 72 L at a sampling rate of 50 cc/min. This method will be important to evaluate and monitor worker exposures in the food and flavoring industry. Samples can be collected over an 8-hour shift with up to 288 L total volume collected regardless of time, sampling rate, and/or the effects of humidity.

scholarly journals A Novel Analytical Method of Cisplatin Using the HPLC with a Naphthylethyl Group Bonded with Silica Gel (πNAP) Column

2017 ◽  
Vol 40 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Ryuji Kato ◽  
Takaji Sato ◽  
Michiko Kanamori ◽  
Mizuho Miyake ◽  
Ayumi Fujimoto ◽  
...  
Keyword(s):  
Silica Gel ◽  
Analytical Method

scholarly journals ANALYSIS OF DISODIUM 5’-GUANYLATE AND DISODIUM 5’-INOSINATE AS FLAVOR ENHANCER IN FOOD SPICES BY THIN-LAYER CHROMATOGRAPHY–DENSITOMETRY

2018 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Viona Prima Dyta ◽  
Harmita . ◽  
Baitha Palanggatan M
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Analytical Method ◽  
Mobile Phase ◽  
Correlation Coefficients ◽  
Optimum Conditions ◽  
Coefficient Variation ◽  
Layer Chromatography ◽  
Flavor Enhancer

Objective: The objective of this study was to obtain an optimum and valid method of analysis to determine the levels of disodium 5’-guanylate (DSG)and disodium 5’-inosinate (DSI) in six samples of spices.Methods: The optimum method was obtained using silica gel 60 F254 as the stationary phase and isopropanol:water:25% ammonia at a ratio of 6:3:1(v/v) as the mobile phase. The developed spots were scanned using a densitometer in absorbance mode at 260 nm. The methods were valid basedon the accuracy criteria (DSG, 99.11–99.96%, and DSI, 98.56–101.05%), precision (DSG, 1.09%, and DSI, 0.49%), and linearity (DSG, r=0.9909, andDSI, r=0.9976).Results: The results showed that the levels of DSG in samples A, B, C, D, E, and F were 0.70%, 0.79%, 0.78%, 0.99%, 1.08%, and 1.08% and those ofDSI were 0.66%, 0.74%, 0.71%, 0.66%, 0.54%, and 0.67%, respectively.Conclusion: The optimum conditions of DSG and DSI for thin-layer chromatography-densitometry were obtained with silica gel 60 F254 as thestationary phase, isopropanol:water:25% ammonia (6:3:1) as the mobile phase, and a maximum wavelength of about 260 nm. Validation resultsindicated that the accuracy of the analytical method for DSG was about 99.11–99.96% with a coefficient variation (precision) of 0.70–1.41%, whilethat for DSI was 98.56–101.05% with a coefficient variation of 0.23–0.75%. The correlation coefficients for the analytical method for DSG and DSIwere 0.9909 and 0.9976, respectively. The results determined that the levels of DSG and DSI in samples A, B, C, D, E, and F were 0.70%/0.60%,0.79%/0.74%, 0.78%/0.71%, 0.99%/0.66%; 1.08%/0.54%, and 1.08%/0.67%, respectively.

Synthesis of inorganic multilayers on chromatographic supports

1981 ◽  
Vol 59 (7) ◽  
pp. 1045-1050 ◽  
Author(s):  
Palitha P. Wickramanayake ◽  
Amares Chatt ◽  
Walter A. Aue
Keyword(s):  
Metal Oxides ◽  
Layer Thickness ◽  
Silica Gel ◽  
Chromium Oxide ◽  
Diatomaceous Earth ◽  
Titanium Oxides ◽  
Chromatographic Evidence

Multilayers of various metal oxides have been produced on typical chromatographic supports such as diatomaceous earth and silica gel. The layer thickness was characterized for phases based on iron and chromium. These data, as well as chromatographic evidence obtained on chromium oxide, suggest that the layers are homogeneous. Similar, but less well characterized layers of aluminum and titanium oxides have been obtained.

Determination of Ethyl Carbamate in Chinese Yellow Rice Wine by Diatomaceous Earth Extraction and GC/MS Method

2015 ◽  
Vol 98 (3) ◽  
pp. 834-838 ◽  
Author(s):  
Pinggu Wu ◽  
Liqun Zhang ◽  
Xianghong Shen ◽  
Liyuan Wang ◽  
Yan Zou ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Determination ◽  
Analytical Method ◽  
Diatomaceous Earth ◽  
Capillary Column ◽  
Internal Standard ◽  
Ethyl Carbamate ◽  
Rice Wine ◽  
Average Recovery

Abstract A sensitive and rapid analytical method based on alkaline diatomaceous earth extraction followed by GC/MS was developed for the quantitative determination of the toxic contaminant ethyl carbamate (EC) in yellow rice wines. The optimal extraction conditions were investigated. With the application of diatomaceous earth extraction, the damage of organic acids to the capillary column was greatly reduced. By using d5-EC as an internal standard for quantitative analysis of EC, the linearity of the calibration curves was good between 10 and 1000 ng/mL. The LOD and LOQ were 1.7 and 5.0 μg/kg, respectively. The spiked level of EC was 5.0–300 μg/kg, and the average recovery of the spikes was between 78.4 and 98.2%, with an RSD between 4.3 and 8.3%. Upon validation by five laboratories when spiked with 50, 100, and 300 μg/kg, the average respective recoveries were 102.9, 102.2, and 98.7% with a RSD between 0.7 and 8.1%. The validation results demonstrated that the method is fast, simple, selective, and suitable for the determination of EC in yellow rice wines.

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