A Clinical Method for the Analysis of Amygdalin in Human Plasma

Abstract

A rapid, simple and sensitive method for the analysis of amygdalin in human plasma has been developed. The method is based on the hydrolytic action of the enzyme 6-glucosidase on amygdalin to yield a molar equivalent amount of benzaldehyde (along with 2 moles of glucose and a mole of HCN). The benzaldehyde is extracted from plasma with chloroform and determined by GLC using a flame ionization detector. The benzaldehyde recovered, when the method was applied to human plasma spiked with amygdalin, was found to be 9.5% of the added amygdalin. Such recovery was highly reproducible (± 1.5%) for amygdalin concentrations ranging from 2 to 20 μg/ml.     

Development and validation of high-performance thin-layer chromatographic method for determination of amygdalin

ABSTRACT

A new method for the extraction and quantitative determination of amygdalin has been proposed. Accelerated solvent extraction was applied for the extraction, and reversed-phase high-performance thin-layer chromatography method was developed, validated, and applied for the determination of amygdalin in the extracts of apricot, plum, almond, and peach kernels. The chromatographic system used was RP-18 silica, as stationary phase and acetonitrile/water (50:50, v/v), as mobile phase. Densitometric scanning was performed at 210 nm. The method was validated with respect to specificity, linearity, precision, and accuracy. The results showed that the peak area responses were linear within the concentration range of 2.5–50.0 µg/spot (R² = 0.9984). The limit of quantification was 4.28 µg/spot, and the detection limit 1.28 µg/spot. The intra-day and inter-day reproducibility, in terms of %RSD, were in the range of 0.81–1.15 and 1.32–1.89, respectively. The accuracy data were in the range from 99.98 to 100.56%. The method is linear, quantitative and reproducible, and could be used as an efficient and economical green chromatographic procedure for the determination of amygdalin in the fruit kernel.     

Determination of the epimerization rate constant of amygdalin by microemulsion electrokinetic chromatography

A new method for separation and determination of amygdalin and its epimer (neoamygdalin) in the epimerization of amygdalin by MEEKC is proposed. For the chiral separation of amygdalin and neoamygdalin, a running buffer composed of 80 mM sodium cholate, 5.0% v/v butan‐1‐ol, 0.5% v/v heptane and 94.5% v/v 30 mM Na₂B₄O₇ buffer (pH 9.00) is proposed. Under optimum conditions, the basic separation of amygdalin and neoamygdalin can be achieved within 7 min. The calibration curve for amygdalin showed excellent linearity in the concentration range of 20–1000 μg/mL with a detection limit of 5.0 μg/mL (S/N=3). The epimerization rate constant of amygdalin in basic microemulsion was first determined by monitoring the concentration changes of amygdalin, and the epimerization rate constant of amygdalin was found to be 2×10^?3 min^?1 at 25°C under the above optimum microemulsion conditions.     

Qualitative and Quantitative Analysis of Amygdalin Using NMR Spectroscopy

Abstract

NMR analytical procedures are described for the qualitative and quantitative determination of amygdalin. The spectrum is very specific for amygdalin, particularly the sugar region. The optical nature may be conveniently ascertained from the chemical shifts of the aglycone methine hydrogens and the relative optical purity determined by comparing the corresponding peak areas. Satisfactory analyses of amygdalin-containing tablets have been carried out with a precision of 1.2% and accuracy of less than 1%.     

The Synthesis of Allolactose from Amygdalin

An original synthetic approach to the disaccharide allolactose (1) starting from the natural glycoside amygdalin (2) has been developed. The disaccharidic gentiobiose unit present in 2 has been transformed into the allolactose moiety using a four step protocol based on the selective inversion of the C‐4′ OH. The efficient removal of the natural benzylic aglycone (a mandelonitrile moiety) was accomplished by catalytic transfer hydrogenolysis. The behavior of allolactose with different enzymes is also described.     

Pyrocatechol-1-Aldehyde 2-Benzothiazolylhydrazone As Reagent for the Spectrofluorimetric Determination of Nanogram Amounts of Gallium in Urine and Blood Serum

Abstract

A method is developed for the spectrofluorimetric determination of 1–80 ng.ml^?1 of gallium with pyrocatechol-1-aldehyde 2-benzothiazolylhydrazone, in a 50% (v/v) DMSO-Water medium at apparent pH 4.0 (monochloracetic/monochloracetate buffer). Λ_ex = 400nm, Λ_em = 504 nm (corrected). Interferences have been evaluated and the method applied to the determination of gallium in human urine and blood serum samples.     

A Simple Electrochemical Method for the Quantitative Determination of Acetaminophen in Serum

Abstract

A simple electrochemical method for the determination of acetaminophen in serum is described. The eleotrode and associated electronics are simple, reliable, and inexpensive to build. The apparatus can be operated at a rate of 2–3 determinations per minute using only 10 μl serum per determination. The procedure includes extraction of acetaminophen in ethyl acetate and subsequent oxidative amperometric detection of the drug by a form of flow-injection analysis. The system parameters of buffer, pH, and redox potential have been optimized to permit measurement of less than 10 μg/ml of acetaminophen. The determination is linear over the range of 10–300 μg/ml with a C.V. of less than 3% for replicate analysis of the same sample.     

A Simple HPLC Method for the Determination of Trazodone Human Serum

Abstract

A simple HPLC method with minimal sample preparation and good reproducibility for the determination of trazodone in serum is described. Basified serum samples were extracted using ethyl acetate containing diazepam as the internal standard (IS). Chromatography was performed on a cyanopropylsilane column with 15 μL sample injection. The mobile phase consisted of 0.02 M ammonium phosphate, pH 7.5 : acetonitrile (70:30 v/v). The eluent was monitored at 220 nm. The serum standard curve was linear from 10.0 to 8000.0 ng/mL serum. The overall within-run quality control CV was 6.3% for five concentrations (20.0, 40.0, 100.0, 250.0 and 1000.0 ng/mL) and the overall recovery from serum was 85.4%. This method has been applied to the analysis of human serum samples.     

Determination of Trace Amounts of Acetaldehyde Using a Novel Chemiluminescence Reaction

Abstract

The chemiluminescent reaction of iso-propyl alcohol with C10^?-H₂O₂ is enhanced by acetaldehyde. This provides a new method for the determination of trace amounts of acetaldehyde. The detection limit is 0.08ng/ml acetaldehyde and the linear dynamic range is 0.5ng/ml to 1000 ng/ml. The method results in good selectivity and has been satisfactorily applied to the determination of traces of acetaldehyde in waste water samples.     

Improved Enzyme Electrode for Amygdalin

Abstract

A new variant of enzymatic electrode for amygdalin is described. It consists of a cyanide-selective membrane electrode on whose; surface a dialysis membrane is fixed which contains covalently immobilized β-glucosidase. The sensor thus achieved ensures improved response characteristics over similar sensors mentioned in literature. Its response to amygdalin is linear within 10^?1 ? 10^?5 moles/1; the response time is smaller and the stability is higher than those of similar sensors described in literature.     

Flow Injection Analysis of Tannic Acid with Inhibited Electrochemiluminescent Detection

ABSTRACT

A flow injection method has been developed for the determination of tannic acid based on its inhibition of the electrochemiluminescence of luminol. The method is simple, rapid and sensitive with a detection limit of 2×10^?8 mol/l. It is effective to determine tannic acid in the range 5×10^?8 - 1×10^?5 mol/l. The variation coefficient of eleven determinations is 1.4% for 5×10^?6 mol/l. The method has been successfully applied to the determination of tannic acid in real Chinese gall and hop pellet samples.     

HPLC Determination of Ochratoxin A in a Low Volume of Human Blood Serum

Abstract

A high‐performance liquid chromatography (HPLC) method has been developed for the determination of ochratoxin A (OTA) in human blood serum. Samples were purified on a C18 solid phase extraction column. The developed method required a relatively low serum volume (0.5 ml). Significant correlation (r of 0.998) was found over the range from 0.10 to 8 ng/ml, with a detection limit of 0.1 ng/ml and better performance in terms of precision and accuracy. Mean recoveries at 0.5 and 2 ng/ml were respectively 69.7±1.2 and 71.9±2.8%. This method was used as a rapid and noninvasive tool to assess human exposure to OTA. Among 40 analyzed serum samples, 27.5% were found to contain OTA with levels going from 0.1 to 11.98 ng/ml with a mean concentration of 0.73±2.35 ng/ml.     

HPLC Determination of Iodide in Scrum Using Paired Ion Chromatography with Electrochemical Detection

Abstract

HPLC utilizing paired ion chromatography with electrochemical detection is used for the determination of iodide in serum. Serum samples are prepared by precipitation of protein, centrifugation and removal of Interfering substances with a bonded phase column. The resulting sample is then analyzed. The method has successfully been applied to human serum and gives data that agrees well with values obtained by other methods. The method is accurate precise, and time conservative when compared to more classical methods.     

A Stability-Indicating Liquid Chromatographic Method for the Analysis of Erythromycin in Stored Biological Fluids Using Amperometric Detection

Abstract

A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. Calibration plots for erythromycin base in serum and urine were linear over the ranges 0.25–5.0 μg/ml and 1.25–25.0 μg/ml respectively, with a sensitivity limit of 0.1 μg/ml.

This method allows both erythromycin and its principle degradation product, anhydroerythromycin, to be determined during a period of sample storage at 4°C and ?15°C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.     

A Method for the Determination of Methionine in Human Serum by High-Performance Liquid Chromatography with Electrochemical Detection

Abstract

We have found remarkable enhancement of electrochemical response for the analysis of methionine by use of a glassy carbon electrode preanodized in a 0.2 M phosphate buffer (KH₂PO₄?KOH, pH 6.5) at +1.9 V vs. Ag/AgCl for 2 min. On the basis of this finding, we have developed a method for the determination of methionine in human serum by reversed-phase high-performance liquid chromatography with electrochemical detection using the electrochemically pretreated glassy carbon electrode. The minimum detectable quantity of methionine has been found to be about 1 ng.     

High-Performance Liquid Chromatographic Determination of Clavulanic Acid in Human Serum and Urine Using a Pre-Column Reaction with 1, 2, 4-Triazole

Abstract

A reversed-phase high-performance liquid chromatographic (RP-HPLC) assay for the determination of clavulanic acid in serum and urine is described. The clavulanic acid was assayed by reacting the sample with 1, 2, 4-triazole reagent which rapidly produces a derivative that has its UV absorption maximum at 317 nm. The resulting product was separated in a RP-18 column (μ-Bondapak, 10 μm) and detected at 313 nm. The method was applied to assays of clavulanate in serum and urine, and is reproducible with a lower limit of quantitation of 0.1 μ/Ml.     

Determination of Formaldehyde in Waste Water by Lucigenin Chemilummescence

Abstract

A chemiluminescence analysis has been developed for the determination of formaldehyde based on its inhibition of the chemiluminescence reaction of lucigenin-C10^?-H₂o₂. The method is sensitive, convenient and selective with a detection limit of 0.05ng/ml. The linear dynamic range is 1.0ng/ml to 0.1 μg/ml. The variation coefficient of ten determinations for 2.Ong/ml formaldehyde is 1.2%. Applications to the trace determination of formaldehyde in industrial waste waters are discussed.     

Determination of Enzymatic Activities Based on an Optical Flow-Through p-Nitrophenol Sensor

Abstract

An optical flow-through biosensor based on the transient retention of p-nitrophenol on an ion-exchange support packed in the flow cell is presented. The approach was applied to the determination of the activity of some enzymes which catalyze the conversion of p-nitrophenyl-derivatives into p-nitrophenol. The method was first developed for determination of p-nitrophenol yielding a linear range between 0.1–5 μg/mL (r² = 0.9922, r.s.d.% less than 2.5), then, it was also applied to the determination of β-D-glucuronidase activity in serum, with a linear range between 0.1–20 U/L (r² = 0.9976, r.s.d.% less than 3.0), and a sampling frequency of 20 h^?1. The application of the method to the determination of the enzyme activity in serum samples provided results consistent with those obtained by a conventional method and recoveries within 95–104%.     

Determination of Fatty Acids by High-Performance Liquid Chromatography with Electrochemical Detection Using A Ferrocene Derivatization Reagent

Abstract

New derivatization method using ferrocene reagents has been developed for the determination of fatty acids by high-performance liquid chromatography with electrochemical detection. Condensation of fatty acids with 3-bromoacetyl-1, 1'-dimethyl-ferrocene was effected in the presence of 18-crown-6 and potassium fluoride. The resulting esters showed the satisfactory sensitivity at +0.60 V vs. an Ag/AgCl reference electrode with a detection limit of 0.5 pmole. Also the high selectivity was obtained by using a twin electrode electrochemical detector. The proposed derivatization method was found applicable to the determination of fatty acids in human serum.     

Micro-Scale Method for Determination of Tobramycin in Serum Using High-Performance Liquid Chromatography

Abstract

A rapid, simple, accurate, and micro-scale method for the determination of tobramycin, sisomicin and netilmicin in serum using high-performance liquid chromatography has been developed. The method is sensitive to 0.3 pg/ml using only 20 μl of serum. The serum is deproteinized with methanol containing an internal standard: sisomicin for the tobramycin, netilmicin for the sisomicin, and sisomicin for the netilmicin. After centrifugation, a counter-ion reagent is added to the supernatant, then an aliquot of the solution is injected into the chromatograph. Tobramycin, sisomicin and netilmicin are separated by reversed-phase, ion-pair chromatography and detected by fluorescence using continuous-flow, post-column derivatization with o-phthalaldehyde. For the tobramycin, within-run and day-to-day variation was below 2.5%. Correlation of this method with microbiological assay and homogeneous enzyme immunoassay was good.