0000000000154547
AUTHOR
Josep F. Ventura-gayete
On-line sample treatment and FT-IR determination of doxylamine succinate in pharmaceuticals
Abstract A low solvent consumption method for Fourier transform infrared spectroscopy (FT-IR) determination of doxylamine succinate in pharmaceuticals has been developed. The analyte was continuous and selectively extracted with a 13% (v/v) ethanol:chloroform solvent mixture, recirculating the solvent through the sample and monitoring the process by FT-IR. Doxylamine succinate was determined by on-line standard addition measuring the peak area in the regions 1730–1710 and 1485–1462 cm −1 corrected with a two-point baseline established between 2000 and 1800 cm −1 . This new method implies low volumes of chloroformic solvent mixture, only 2.6 mL per sample, in front of classical batch FT-IR m…
Determination of biochemical parameters in human serum by near-infrared spectroscopy
NIR offers multiple advantages for serum analysis, permitting a fast and direct determination of several parameters simultaneously, with low sample handling and without the need for reagents during the measurement step. The aim of this paper was to provide an evaluation of this technique in a real world scale, for the simultaneous determination of several parameters and based on a considerable number of samples. Direct near infrared (NIR) absorbance measurements were used to determine the concentration of clinical parameters in human serum that are required in routine biochemical tests. Total protein, albumin, total cholesterol, high-density lipoprotein (HDL cholesterol), low-density lipopr…
Evaluation of infrared spectroscopy as a screening tool for serum analysis
Abstract The application of attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy to the determination of clinical parameters in serum using partial least squares (PLS) has been evaluated as a point-of-care diagnostic tool. In this study the effect of using an increased size of the calibration set and the influence of the origin of samples and their interyear variation on the prediction capability of the method were considered. PLS-ATR-FT-IR provides a green, fast and cheap point-of-care tool for the determination of total protein. Albumin, glucose, urea, HDL, LDL and total cholesterol were predicted with relative errors between 15 and 32%. The analytical predicti…
Attenuated total reflectance infrared determination of sodium nitrilotriacetate in alkaline liquid detergents
Abstract An attenuated total reflectance infrared (ATR–FTIR) method has been developed for the direct determination of the chelating agent sodium nitrilotriacetate (NTA) in high pH cleaning formulations. Aqueous samples and standards were placed directly on the diamond ATR cell without any pre-treatment and FTIR spectra were recorded between 4000 and 600 cm−1. Measurement conditions were evaluated. Results obtained for five different commercial formulations containing from 6.22 to 9.25% (w/w) of NTA were in good agreement with the manufacturer's declared content (differences between 3.2 and −3.7%). Recovery studies evidenced the accuracy of the developed method, having found values between …
Multicommutation-NIR determination of Hexythiazox in pesticide formulations.
A multicommutated flow-system was designed in order to increase analytical throughput and for controlling thermal effects on the NIR spectra for determination of Hexythiazox in pesticide formulations. An on-line standard addition was carried out showing the versatility and repeatability of multicommutation for the on-line mixing and dilution of solutions. Results obtained for commercial samples were statistically comparable with those obtained by an HPLC-reference method. Multicommutation-NIR allows the analysis of 52 samples per hour, in front of the 30 samples per hour analyzed by the NIR-batch procedure and the 7 samples per hour analyzed by HPLC-reference method.
Multicommutation ATR-FTIR: determination of sodium alpha-olefin sulfonate in detergent formulations
Abstract The mechanization of attenuated total reflectance measurements (ATR) in Fourier Transform Infrared spectrometry (FTIR) through the use of multicommutation has been evaluated in order to reduce the sample consumption and waste generation also avoiding risks of cells breaking. A new multicommutation ATR-FTIR procedure has been proposed for the determination of sodium alpha-olefin sulfonate (AOS) in liquid detergent formulations. The main advantages of this method are the low consumption of sample (96 ml per 100 determinations) and the analytical throughput (23 h −1 versus 15 h −1 for the manual mode). Results obtained for reference samples containing 7.52% to 9.52% (w/w) of AOS are i…
A multicommutated flow system for determination of bismuth in milk shakes by hydride generation atomic fluorescence spectrometry incorporating on-line neutralization of waste effluent
Abstract A highly sensitive method was developed for determination of bismuth in milk shakes by multicommutation hydride generation atomic fluorescence spectrometry (HG-AFS) based on off-line sonication for 10 min with aqua regia 8% (v/v) and on-line waste treatment. The instrumentation and chemistry variables were studied in order to provide the best performance. The limit of detection in the original samples, established for a probability level of 99.6% (k = 3), was 1.67 ng/g Bi. The method provides a fast alternative in control analysis with a sampling throughput of 72 h as compared with 31 h obtained by the classical continuous measurement. Additionally, multicommutation reduces waste g…
Chemometric determination of lipidic parameters in serum using ATR measurements of dry films of solvent extracts
Attenuated total reflectance (ATR) infrared spectroscopy of dried organic extracts of serum samples has been evaluated as a fast method for the determination of triglycerides, cholesterol, high density lipoprotein (HDL) and low density lipoprotein (LDL). After careful selection of solvents based on green parameters, serum samples were extracted using hexane-isopropanol and ethyl acetate-ethanol mixtures. Microscopy studies and comparison with standard spectra were performed in order to investigate whether the proposed methodology is suitable for the quantification of lipids in serum samples. The results of these preliminary studies confirmed that the variations in the IR spectra of sample e…
Multicommutation Fourier transform infrared determination of benzene in gasoline
A fully mechanized method to determine benzene in motor gasolines has been developed based on the use of Fourier transform infrared spectroscopy (FT-IR) and multicommutation. The flow network comprised a set of three-way solenoid valves and was controlled by means of a microcomputer furnished with an electronic interface and running by a software written in QUICK BASIC 4.5. The flow network and control software were designed to implement the multicommutation approach providing facilities to handle sample and reagent solutions, so that, sample dilution, external calibration and standard addition could be easily performed on-line. The method permits the direct determination of benzene without…