Addendum to "tentative method for the continuous analysis of total hydrocarbons in the atmosphere (flame ionization method)": flame ionization detector.
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Air Ionization↗
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Triacylglycerol analysis of potential margarine base stocks by high-performance liquid chromatography with atmospheric pressure chemical ionization mass spectrometry and flame ionization detection.
Several margarine base stock candidates have previously been prepared for the purpose of finding better, more oxidatively stable food components: high-saturate vegetable oils, randomized vegetable oils, vegetable oil-hard stock blends, and interesterified vegetable oil-hard stock blends. Here are reported the triacylglycerol compositions of these products, determined using reverse-phase high-performance liquid chromatography (HPLC) coupled with a flame ionization detector or a quadrupole mass spectrometer with an atmospheric pressure chemical ionization source. Triacylglycerol percent composition results for samples of known composition (randomized and interesterified samples) exhibited less average error by HPLC coupled with a quadrupole mass spectrometer with an atmospheric pressure chemical ionization source, after application of response factors, than the results by HPLC coupled with a flame ionization detector. The fatty acid compositions calculated from the mass spectrometric data exhibited less average error than the fatty acid compositions resulting from the flame ionization detector data. The average error of the fatty acid compositions by the mass spectrometer was lowest for interesterified blend samples, next lowest for randomized samples, then followed by high-saturated fatty acid oils, normal oils, and blends. Analysis of the vegetable oil-hard stock blends by mass spectrometer required special treatment for calculation of response factors.
Chromatography, High Pressure Liquid↗
Analysis of triacylglycerol positional isomers in food products as brominated derivatives by high-performance liquid chromatography coupled with a flame ionization detection.
Reversed-phase HPLC resolution and HPLC-flame ionization detection quantitation of model triacylglycerol positional isomer pairs (important in the study of food formulation lipids) after facile conversion to brominated derivatives is reported. The positional isomers in the triacylglycerol pairs were at least 98% resolved from each other during reversed-phase HPLC. Triacylglycerol quantitation obtained by HPLC-flame ionization detector was checked against standard positional isomer pairs known by mass. The flame ionization detection area percent gave absolute error range of 0.3-1.6% per triacylglycerol.
Bromine↗
Improved reproducibility and quantitative analysis of phospholipids by flame ionization detection.
Quantitative analysis of phospholipids by flame ionization was improved by careful application of samples with a Hamilton syringe and use of a sealed dual tank system. Chromarods developed more consistently with reproducible scanning times or RF values (coefficient of variation of 1%) and with sharper peaks if development was carried out in a sealed dual tank system. The Chromarods were placed in the inner tank, which was the standard ground glass topped tank furnished with the Iatroscan TH-10 system. This inner tank was placed inside a larger thin-layer chromatography tank which was sealed with silicone grease and the lid held in place with a lead brick. Both tanks were lined with absorbent paper and contained the same solvent system. Biological samples quantified with these procedures and measured in amounts between 1 and 30 micrograms had coefficients of variation between 0.2 and 6%. An efficient method of completely separating neutral lipids from phospholipids and allowing quantitative determination of cholesterol is described. Scanning times and RF values of various phospholipids are compared to determine the best separation of the major phospholipids found in 3T3-L1 and leukocyte membranes.
Cell Membrane↗
A simple screening method for plasma lipids by thin-layer chromatography with flame ionization detection.
Thin-layer chromatography was carried out on glass rods coated with Silica gel (chromarod) and the fractions were detected with a flame ionization detector (FID). This system was applied to the fractionation and screening of plasma lipids. As the relative response of the flame ionization detector depends on the nature of the lipids, correction factors had to be introduced. These correction factors were derived from comparison of the results of the thin-layer chromatography with flame ionization detection with those obtained by conventional chemical analysis of the same sample. The coefficients of variation of the lipid profiles were comparable for both techniques. The absolute lipid concentration for the various fractions obtained by combination of the concentration of the total lipids with the relative lipid profile, correlate very well with the values obtained by conventional chemical analysis of the various lipids.
Cholesterol↗
Combined Determination of Poly-beta-Hydroxyalkanoic and Cellular Fatty Acids in Starved Marine Bacteria and Sewage Sludge by Gas Chromatography with Flame Ionization or Mass Spectrometry Detection.
Extraction of lipids from bacterial cells or sewage sludge samples followed by simple and rapid extraction procedures and room temperature esterification with pentafluorobenzylbromide allowed combined determinations of poly-beta-hydroxyalkanoate constituents and fatty acids. Capillary gas chromatography and flame ionization or mass spectrometric detection was used. Flame ionization permitted determination with a coefficient of variation ranging from 10 to 27% at the picomolar level, whereas quantitative chemical ionization mass spectrometry afforded sensitivities for poly-beta-hydroxyalkanoate constituuents in the attomolar range. The latter technique suggests the possibility of measuring such components in bacterial assemblies with as few as 10 cells. With the described technique using flame ionization detection, it was possible to study the rapid formation of poly-beta-hydroxyalkanoate during feeding of a starved marine bacterium isolate with a complex medium or glucose and correlate the findings to changes in cell volumes. Mass spectrometric detection of short beta-hydroxy acids in activated sewage sludge revealed the presence of 3-hydroxybutyric, 3-hydroxyhexanoic, and 3-hydroxyoctanoic acids in the relative proportions of 56, 5 and 39%, respectively. No odd-chain beta-hydroxy acids were found.
Journal Article↗
GLC analysis of hydrocortisone, triamcinolone acetonide, and desonide in culture media of mouse and human dermal fibroblasts using flame-ionization detection.
A quantitative GLC assay with flame-ionization detection capable of detecting nanogram quantities of hydrocortisone, triamcinolone acetonide, and desonide in biological fluids was developed. This assay consisted of two extractions of the glucocorticoids from 1 N sodium chloride-treated cell culture media into ethyl acetate and subsequent double derivatization with methoxyamine and N-trimethylsilylimidazole. The chemical structures of methoxime-trimethylsilyl derivatives were confirmed by GLC-mass spectrometry. The methoxime-trimethylsilyl derivatives were stable for 24 hr. The applicability of this assay was demonstrated by studies of the glucocorticoid levels in L-929 and human dermal fibroblasts cell culture media over prolonged incubation (0--96 hr).
Adult↗
Separation and determination of polyether carboxylic antibiotics from Streptomyces hygroscopicus NRRL B 1865 by thin-layer chromatography with flame ionization detection.
Thin-layer chromatography coupled with flame ionization detection was used to develop a method to separate and to determine simultaneously three polyether carboxylic ionophore antibiotics (abierixin, nigericin and grisorixin) produced by Streptomyces hygroscopicus NRRL B 1865. Various proportions of chloroform, methanol and formic acid (or acetic acid as a substitute for formic acid) were used in the developing solvent to determine changes in RF values of the antibiotics and to allow conditions for maximum resolution to be obtained. Development on Chromarods SII with chloroform-methanol-formic acid (97:4:0.6, v/v/v) gave satisfactory and reliable separations of the three polyether antibiotics. Under these conditions, the internal standard methyl desoxycholate was found to be suitable for their simultaneous determination in the lipid extracts of Streptomyces hygroscopicus NRRL B 1865.
Calibration↗
A novel miniaturized flame ionization detector for portable gas chromatography.
A novel miniaturized flame ionization detector (FID) operated by battery, which can be used as a detector in portable gas chromatography (GC) is devised and manufactured. It is characterized by the structure of building blocks, small volume, low energy consumption, and needing only two gases, which can be used for detection of hydrocarbons in portable GC. The miniaturized detector mainly includes a porous metallic diffuser plate, bugle-figuration collector, quartz capillary flame tip, and self-heated system. The miniaturized FID is easy to fabricate and assemble because of its structure of building blocks. The FID response is linear over six orders of magnitude and the detection limit of 0.518 ng for benzene, 0.430 ng for n-dodecane, 0.473 ng for naphthalene, and 0.509 ng for n-tetradecane.
Alkanes↗
Separation and quantitation of molecular species of plant phosphatidylcholine by high-performance liquid chromatography with flame ionization detection.
A method is described for the direct quantitation of phosphatidylcholine molecular species by reverse phase high-performance liquid chromatography employing flame ionization detection. The method is shown to be applicable to plan phosphatidylcholine. The molecular species are separated with a C18 column eluted in an isocratic mode. Detection by a commercially available flame ionization detector overcomes the problems of detecting underivatized naturally occurring lipids using ultraviolet detectors, and allows direct and rapid mass determination of the resolved molecular species. Detection limits for quantitation are defined.
Chromatography, High Pressure Liquid↗
Determination of sodium dodecyl sulfate in hydrophilic ointments by thin-layer chromatography with flame ionization detection.
Thin-layer chromatography with flame ionization detection (TLC-FID) was compared with colorimetric and HPLC methods for measuring sodium dodecyl sulfate (SDS), an anionic surfactant, in hydrophilic ointments prepared according to the Japanese Pharmacopoeia, the United States Pharmacopoeia and British Pharmacopoeia. The TLC-FID method was found to be better than the colorimetric method in terms of simplicity and accuracy in the determination of SDS in hydrophilic ointments. Quantification of a small amount of SDS was not possible using HPLC with refractive index detection due to the low sensitivity of the detector.
Chemical Phenomena↗
HPLC separations with micro-bore columns using high-temperature water and flame ionization detection.
Previous work demonstrates that a flame ionization detector (FID) may be used as a detector for high-temperature water separation. However, the relatively high flow rate of the eluent required by standard high-performance liquid chromatography columns causes instability of the FID. In this work, micro-bore columns are packed with poly(styrene-divinylbenzene) (PRP-1) or Daiso gel octadecylsilane-bonded phase particles. Because micro columns require low volume flow rates, the eluent used in high-temperature water chromatography does not cause instability of the FID. Separation of carbohydrates, amino acids, and other organic acids and bases is performed on two micro-bore columns using a homemade high-temperature water chromatograph with FID. Both isothermal and programmed temperatures are used in this work. The limit of detection and the linear range are also determined for amino acids tested.
Journal Article↗
Quantitative gas-chromatographic flame-ionization method for chloramphenicol in human serum.
We describe a flame-ionization gas-chromatographic procedure for determination of the potentially toxic antibiotic, chloramphenical, in serum. The serum (500 mul) is extracted into ethyl acetate and nonpolar impurities are subsequently partitioned into hexane. The drug is chromatographed as its bis-trimethylsilyl derivative, with the analog thiamphenicol as the internal standard. Within-run precision (CV) is 4.4% at a serum concentration of 41 mg/liter and 9.2% at a concentration of 5 mg/liter. Over a six-month period, the run-to-run variation was 5.1% at 40 mg/liter (n = 24). Results by the gas-chromatographic method compared well with those by an established colorimetric procedure; mean concentrations for the comparison samples in the two procedures were 18.4 mg/liter and 17.6 mg/liter, respectively (n = 27), with a coefficient of correlation of 0.998. The gas-chromatographic method is more precise and specific than classical microbiological procedures and is suitable for routine therapeutic monitoring of serum chloramphenicol concentrations.
Chloramphenicol↗
Trace analysis of residual methyl methanesulfonate, ethyl methanesulfonate and isopropyl methanesulfonate in pharmaceuticals by capillary gas chromatography with flame ionization detection.
A capillary gas chromatographic method using flame ionization detection was developed and validated for the trace analysis (ppm level) of methyl methanesulfonate, ethyl methanesulfonate, and isopropyl methanesulfonate in pharmaceutical drug substance. The method utilizes a megabore capillary column with bonded and crosslinked polyethylene glycol stationary phase. A dissolve-and-injection approach was adopted for sample introduction in a splitless mode. The investigated sample solvents include acetonitrile, ethyl acetate, methylene chloride, 1,2-dichloromethane, and toluene. Aqueous mixtures of acetonitrile and water can also be used as sample solvent. A limit of detection of about 1 microg/g (1 ppm) and limit of quantitation of 5 microg/g (5 ppm) were achieved for the mesylate esters in drug substance samples. The method optimization and validation are also discussed in this paper.
Chromatography, Gas↗
Monitoring of monooctanoylphosphatidylcholine synthesis by enzymatic acidolysis between soybean phosphatidylcholine and caprylic acid by thin-layer chromatography with a flame ionization detector.
Thin-layer chromatography with a flame ionization detector (TLC-FID) was used for monitoring the production of structured phospholipids (ML type: L, long-chain fatty acids; M, medium-chain fatty acids) by enzyme-catalyzed acidolysis between soybean phosphatidylcholine (PC) and caprylic acid. It was found that the structured PC fractionated into two to three distinct bands on both plate thin-layer chromatography (TLC) and Chromarod TLC. These three bands represented PC of the LL type, ML type, and MM type, respectively. The TLC-FID method was applied in the present study to examine the influence of enzyme dosage, reaction temperature, solvent amount, reaction time, and substrate ratio (caprylic acid/PC, mol/mol) on formation of ML-type PC in a batch reactor with Thermomyces lanuginosa lipase as the catalyst. The formation of ML-type PC was dependent on all parameters examined except for the substrate ratio. The ML-type PC content increased with increasing enzyme dosage, reaction temperature, solvent amount, and reaction time. The substrate ratio had no significant effect on the formation of ML-type PC within the tested range (3-15 mol/mol). The formation of MM-type PC was observed in some experiments, indicating that acyl migration is taking place during reaction since the lipase is claimed to be 1,3-specific. The TLC-FID method offers a simple and cheap technique for elucidation of product and byproduct formation during enzyme-catalyzed reactions for production of phospholipids containing mixtures of long- and medium-chain fatty acids.
Caprylates↗
Influence of tryptophan loading on urinary excretion of anthranilic acid and 3-hydroxyanthranilic acid by men and women as determined by alkali flame ionization gas chromatography.
A gas chromatographic method with alkali flame ionization detection is described for the determination of urinary total (free and conjugated) anthranilic acid (AA) and 3-hydroxyanthranilic acid (HAA) as their pentafluorobenzyl esters. Prior to analysis, urine was hydrolysed using hydrochloric acid in a boiling water bath. The highest AA and HAA yields were obtained with 4 M hydrochloric acid and a hydrolysis time of 4 h. The coefficients of variation of the between-run analyses of AA and HAA at the endogenous level were 7.2 and 5.8%, respectively. The average recovery for both substances was 84%. The method described has been used to study the excretion of AA and HAA in the urine of healthy males and females before and after an oral load of tryptophan. Furthermore, the influence of oral contraceptives has been investigated. Results indicate that for both sexes the excretion of AA in the urine was higher than that of HAA, except after tryptophan loading. The excretion of AA by women was higher than by men. For HAA, the results of both sexes were comparable. Furthermore, for neither of the sexes was a diurnal variation of AA or HAA observed. After tryptophan loading, the formation of HAA was increased by more than that of AA. Results obtained for women on oral contraceptives indicate a hormonal-induced inhibition of AA formation.
3-Hydroxyanthranilic Acid↗
Determination of fruit juice authenticity by capillary gas chromatography with flame ionization detection.
A method using capillary gas chromatography with flame ionization detection was developed to determine the addition of high-fructose syrup and beet or cane invert syrup to apple or orange juice. Fingerprint oligosaccharides in these inexpensive sweeteners were not detectable (area < 1000) in pure apple or orange juice. One hundred twenty-three pure apple juice and 60 pure orange juice samples representing growing regions around the world were analyzed. Ten samples were intentionally adulterated with each sweetener at levels of 5, 10, and 15%. The detection limit for each sweetener was 5%.
Beverages↗
Flame-ionization GLC assay for fluorouracil in plasma of cancer patients.
A rapid and specific flame-ionization GLC method was developed for the determination of plasma fluorouracil. The chloro analog is used as the internal standard. The method involves the isolation of both the drug and the internal standard from plasma on a strong anion-exchange column at pH 10. Elution is performed with acetic acid in methanol. The evaporated eluate is dissolved in tetrahexylammonium hydroxide. An aliquot of the resulting solution is introduced directly into the gas chromatograph, where conversion to the bishexyl derivatives and subsequent separation take place. The extraction recovery from blank plasma, to which fluorouracil was added, was 96.8 +/- 2.4% (SD). Linearity was proven in the range from 0 to 25 micrograms/ml, whereas the detection limit of the method was estimated at about 2 micrograms/ml of plasma. The within-run precision was determined at three different fluorouracil levels. To demonstrate method applicability, plasma samples obtained from cancer patients to whom 1 g of fluorouracil had been administered intravenously were analyzed.
Alkylation↗