Determination Of Fluorescent Whitening Agents Research Articles

Studies on analytical method for determination of fluorescent whitening agents in paper containers for food

The method of determination of fluorescent whitening agents (FWA) in paper containers for food was studied. Samples were assessed in accordance with official procedures. The treated gauze was extracted by dimethylformamide, evaporated to dryness, and then analyzed by HPLC. The extracted FWAs were separated with Prodigy 5 μm ODS (2) column using acetonitrile: 0.01 M sodium dihydrogen phosphate (35:65) as solvent. For spectrofluorimetric detection, an excitation wavelength of 340 nm and emission wavelength of 430 nm were used. Applying the above HPLC method, fifty samples of paper containers for food were analyzed. No residue of FWA was detected in any sample.

Magnetic-covalent organic polymer solid-phase extraction coupled with high-performance liquid chromatography for the sensitive determination of fluorescent whitening agents in cosmetics.

Magnetic solid-phase extraction is a powerful sample preparation tool. Combined with covalent organic polymers, this technique permits an excellent extraction performance. We present a sensitive, efficient, and easy operating magnetic- covalent organic polymer solid-phase extraction method. By using the magnetic covalent organic polymer nanoparticles yielded by a one-pot reaction, five fluorescent whitening agents were successfully preconcentrated and separated. The saturated extraction amounts of the magnetic covalent organic polymer nanoparticles for the five fluorescent whitening agents were in the range of 97-155nmol/mg. Coupled with high-performance liquid chromatography, the limit of detection of the fluorescent whitening agent was improved by at least an order of magnitude compared to current literature records. Under the optimal conditions, the linear ranges of these five fluorescent whitening agents were up to 0.5-100ng/L, the limit of detection was as low as 0.1ng/L, and the recoveries were in the range of 78.2-105% with relative standard deviations lower than 5.5%. Meanwhile, a trace level of 7-diethylamino-4-methylcoumarin was found in a typical cosmetic sample by using this magnetic-covalent organic polymer solid-phase extraction method when coupling with high-performance liquid chromatography. Moreover, this sensitive, efficient, and easy operating sample preparation method can be extended to analysis of other analytes that have a π-π conjugated structure.

Development and validation of an HPLC method with fluorescence detection for the determination of fluorescent whitening agents migrating from plastic beverage cups

ABSTRACTAn HPLC method with fluorescence detection has been developed and validated for the quantification of six fluorescent whitening agents (FWA) in plastic beverage cups after extraction and in food simulants after migration at 70°C for 2 h. The sensitivity of the method was high with LODs ranging from 0.053 to 0.251 μg kg−1 and LOQs from 0.107 to 0.504 μg kg−1. Accuracy and precision were highly acceptable, with recoveries greater than 82% and RSDs (%) below 16%. The expanded combined uncertainty was found to be less than 23% for the measurements of all studied FWAs. In extracting the analytes from food contact materials (FCM), accelerated solvent extraction (ASE) and Soxhlet extraction were applied using ethanol as the extraction solvent. The results obtained for FWA in 10 different food plastic cups, made from different polymers, were compared. The ASE technique proved to be faster, more effective and efficient than Soxhlet extraction. Migration tests with official food simulants from Regulation (EU) No 10/2011 showed that the substances studied could potentially migrate using the selected migration conditions. The most pronounced effect was observed in case of simulant D1 (50% w/v ethanol in water). The analytical method proved to be a simple, fast, sensitive and reliable tool for the simultaneous quantification of six of the most used FWAs in both FCM extracts and food simulants after migration experiments.

Facile synthesis of polymer monolith functionalized with layered double hydroxide as effective preconcentration materials for fluorescent whitening agents

In the current study, a novel monolithic capillary column functionalized with layered double hydroxide (LDH) was developed and exploited for the separation and preconcentration of fluorescent whitening agents combined with high performance liquid chromatography. Mg-Al LDH was embedded in the poly(dimethyl diallyl ammonium chloride-ethylene dimethacrylate) monolith via in situ polymerization. The ratio of LDH introduced into the polymerization mixtures was finely investigated. The characteristic properties of LDH and functionalized monolith were carefully characterized using X-ray diffraction, scanning electron microscope, Fourier-transformed infrared spectra, and thermal gravimetric analysis. After optimizing various experimental parameters, the developed method was validated and applied to the determination of fluorescent whitening agents in mask essence samples.

Simultaneous determination of fluorescent whitening agents (FWAs) and photoinitiators (PIs) in food packaging coated paper products by the UPLC-MS/MS method using ESI positive and negative switching modes

A sensitive ultra-high performance liquid chromatography tandem mass spectrometry method is established for the simultaneous determination of FWAs and PIs in food packaging.

Determination of fluorescent whitening agents in disposable sanitary products by high performance liquid chromatography

A method for the determination of four fluorescent whitening agents (FWAs) (FWA 357, FWA 220, FWA 204 and FWA 113) in disposable sanitary products by high performance liquid chromatography with diode array detection (HPLC-DAD) was developed. The sample was extracted with a 20 mL ultrapure water by sonication for 30 min at 80 °C. The HPLC method was performed on an SB Phenyl column (250 mm x 4. 6 mm, 5 µm) by gradient elution using 5 mmol/L ammonium acetate and acetonitrile as mobile phases, which can separate the target analytes successfully. The target analytes showed good linearity in the range of 0. 025-400 mg/L with the correlation coefficients (r2) greater than 0. 999 9. The limits of detection (LODs, S/N =3) were 0.02-0. 1 mg/L, and the method limits of quantification (MLOQs) were 1. 0 - 5. 0 mg/kg for the target analytes. The feasibility of this method was demonstrated by the determination of FWAs in samples with spiked recoveries. The recoveries were in the range between 83. 7% and 101. 0%, and the relative standard deviations (RSDs) (n=6) ranged from 2. 4% to 7. 0%. This method is simple, and has high recoveries for the determination of FWAs in disposable sanitary products.

Determination of four fluorescent whitening agents in laundry detergents by solid phase extraction combined with ultra-high performance liquid chromatography

A new method was established to determine three stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWA351, FWA85, FWA28 and FWA71) in laundry detergents by solid phase extraction (SPE) and ultra-high performance liquid chromatography with a diode array detector (UPLC-DAD). The fluorescent whitening agents were extracted from laundry detergents with 2% formic acid aqueous solution and methanol, and purified by WAX SPE column, and analyzed by UPLC-DAD on a Phenomenex Synergi Max-RP column (150 mm x 2.0 mm), employing acetonitrile-10 mmol/L ammonium acetate as the mobile phase in a gradient elution mode. The fluorescent whitening agents were qualitatively determined by retention time, and confirmed by the ultraviolet spectrum. The results indicated that the target analytes were in the range of 0.05-180 mg/L with the correlation coefficients (r) greater than 0. 999 3, and the method limits of quantification (MLOQ) of target analytes were ranged from 1.5 mg/kg to 15 mg/kg (S/N = 10). The feasibility of this method was demonstrated by the determination of FWAs in samples with spiked recoveries. The recoveries were in the range between 84.9% and 105%, and the precision (relative standard deviation, RSD) ranged from 3.2% to 6.1% (n = 6). Among the 15 samples analyzed, the rate of positive samples was 53.3%, over 1 000 mg/kg of FWA351 and FWA71 were detected. The method is simple, precise and has high recoveries for the determination of fluorescent whitening agents in laundry detergent samples.

Determination of fluorescent whitening agents in plastic food contact materials by high performance liquid chromatography with fluorescence detector

A method for the determination of fluorescent whitening agents in plastic food contact materials by high performance liquid chromatography (HPLC) with fluorescence detector was developed. The samples were extracted with trichloromethane by sonication for 30 min at 40 degrees C. The HPLC method was performed on a column of Eclipse XDB-C18 (250 mm x 4.6 mm, 5 microm) by gradient elution using 5 mmol/L ammonium acetate and acetonitrile as the mobile phases, and detected by the fluorescence detector at an excitation wavelength of 350 nm and an emission wavelength of 430 nm. The experimental results indicated that the four fluorescent whitening agents were separated well. The limits of detection (LOD) (S/N = 3) were 0.3, 0.1, 0.05, 0.14 mg/L, and the limits of quantification (LOQ) (S/N = 10) were 1.0, 0.4, 0.2, 0.5 mg/L for 1,4-bis (4-cyanostyryl) benzene (C. I. 199), 1,4-bis (2-benzoxazolyl) naphthalene (C. I. 367), 4,4'-bis(2-methoxystyryl) biphenyl (C. I. 378) and 2,5-thiophenediylbis (5-tert-butyl-1,3-benzoxazole) (C. I. 184), respectively. Good linearities with correlation coefficients (r2) not less than 0.991 were obtained. The proposed method is simple, accurate, sensitive and can meet the requirements of the routine determination of fluorescent whitening agents in entry-exit products.

Determination of Fluorescent Whitening Agents in Paper Materials by Ion-Pair Reversed-Phase High-Performance Liquid Chromatography

A simple method was developed for the analysis of seven stilbene-type fluorescent whitening agents (FWAs) in paper materials by ion-pair reversed-phase high-performance liquid chromatography with fluorescence detection. These stilbene-type FWAs included two disulfonate, two tetrasulfonate, and three hexasulfonate compounds. After optimization of chromatographic conditions, the FWAs were satisfactorily separated using a reversed-phase column (RP-18) with the following isocratic mobile phase: methanol-water (60:40) containing 17.5 mM TBABr and 10 mM citrate buffer (pH = 7.0). The calibration plot was linear in the range from 5 to 500 ng/mL for two disulfo-FWAs and from 1 to 500 ng/mL for the other five FWAs. Precision levels of the calibration curve as indicated by RSD of response factors were 1.2 and 8.1%. Limits of quantitation (LOQ) ranged from 1.2 to 11 ng/mL.

Determination of Fluorescent Whitening Agents in Infant Clothes and Paper Materials by Ion‐Pair Chromatography and Fluorescence Detection

AbstractA simple and rapid method was developed to simultaneously determine four stilbene‐type disulfonate and one distyrylbiphenyl‐type fluorescent whitening agents (FWAs) in infant clothes and paper materials by ion‐pair chromatography. FWAs were extracted from cloth and papers samples using a hot‐water extraction. The aqueous extract was then mixed with ion‐pair reagent, extracted with C18‐SPE cartridges and eluted with methanol. The contents of FWAs were determined by an isocratic ion‐pair chromatography with RP‐C18 column and equipped with fluorescence detection. Limits of quantitation were 0.04 to 0.45 ng/g in 10 g of samples. Recovery of FWAs in spiked infant cloth and paper samples was between 76 to 92% and precision (RSD) ranging from 2.0 to 4.0%. Analysis of three infant clothes and six paper materials found concentrations of selected FWAs ranging between n.d. to 24 μg/g and n.d. to 3.8 μg/g, respectively.

Determination of fluorescent whitening agents in environmental waters by solid-phase extraction and ion pair liquid chromatography–tandem mass spectrometry

A comprehensive method for the trace determination of four stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWAs) in environmental water samples was developed and validated. Various solid-phase extraction (SPE) cartridges were investigated. The newly developed Oasis WAX (weak mixed-mode anion exchange and reversed-phase sorbent) SPE cartridge provides the optimal sample extraction results. The analytes were then identified and quantitated by liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC–ESI-MS–MS) in negative ionization mode, applying di- n-hexylammonium acetate (DHAA) as the ion-pairing reagent in mobile phase. Limits of quantitation (LOQs) were established between 4 and 18 ng/l in 50 ml of water samples. Intrabatch and interbatch precision with their accuracy at two concentration levels were also investigated. Precision for these five FWAs, as indicated by RSD, proved to be less than 13 and 11%, respectively, for intra- and interbatch. Accuracy, expressed as the mean recovery, was between 68 and 97%. The method was finally applied to environmental water samples, showing the occurrence of five FWAs in both river water and wastewater treatment plant (WWTP) effluent samples.

Determination of fluorescent whitening agents in laundry detergents and surface waters by solid-phase extraction and ion-pair high-performance liquid chromatography

A simple method was developed to detect four stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWAs) in household laundry detergents and surface waters by ion-pair high-performance liquid chromatography. The FWA concentrations in detergents were measured directly. The contents of FWAs in water samples were extracted by solid-phase extraction (C 18-SPE) with ion-pairing reagent, and were then determined by an isocratic ion-pair chromatography (IPC) using a C 18 column, applying tetrabutylammonium hydrogensulfate (TBA) as the ion-pairing reagent in mobile phase, and equipped with fluorescence detection. Water samples at various pH conditions for SPE were evaluated. Experimental results indicate that the proposed method is precise and sensitive in analyzing FWAs, and enables quantitation of 0.01–0.1 μg/l in 100 ml water samples. The recovery rates of FWAs in spiked water samples were between 73 and 89%, and the precision (RSD) ranged from 2.6 to 8.9%. Over 7200 μg/g of 4,4′-bis(2-sulfostryl)-biphenyl (DSBP) and 2320 μg/g of 4,4′-bis[(4-anilino-6-morpholino-1,3,5-triazine-2-yl)-amino]stilbene-2,2′-disulfonate (DAS1) were detected in household laundry detergents. Trace amounts of DSBP were detected in surface water samples ranging from 0.2 to 3.7 μg/l.

Determination of fluorescent whitening agents in paper and board packaging materials by capillary electrophoresis

Fluorescent whitening agents (FWAs) are large, conjugated, anionic substances added to paper and board during manufacture to impart “whiteness” and “brightness.” A method has been developed to determine disulfo-, tetrasulfo-, and hexasulfo-FWAs in paper and board using capillary electrophoresis (CE). Fluorescent whitening agents are extracted from paper samples using a standard hot-water extraction. The extracts are analyzed by free-flow CE using ammonium acetate (100 mM, pH 9.0) as the run buffer. Fluorescent whitening agents are detected by through-column ultraviolet (UV) scanning between 195 and 365 nm. Limits of detection (mg/kg paper) ranged between 2 and 12 mg/kg with recoveries between 84 and 92%. Analysis of three samples of commercial “take-out” food packaging found concentrations of tetrasulfo-FWA ranging between 200 and 223 mg/kg with no interferences. This is similar to concentrations found in a previous study using liquid chromatography. ©1999 John Wiley & Sons, Inc. J Micro Sep 11: 259–262, 1999. Published 1999 John Wiley & Sons, Inc.

Determination of fluorescent whitening agents in paper and board packaging materials by capillary electrophoresis

Determination of fluorescent whitening agents in paper and board packaging materials by capillary electrophoresis

Determination of fluorescent whitening agents in river waters with high performance liquid chromatography.

A simultaneous method for the determination of fluorescent Whitening agents (FWA), such as disodium 4, 4'-bis [(4-anilino-6-morpholino-1, 3, 5-triazin-2-yl) amino] stilbene-2, 2'-disulfonate (FB 71, trans isomer), disodium 4, 4'-bis [(4-toluidino-6-morpholino-1, 3, 5-triazin-2-yl) amino] stilbene-2, 2'-disulfonate (FB 225, trans isomer and cis isomer) and disodium 4, 4'-bis (2-sulfo-styryl) biphenyl (FB 351, trans isomer and cis isomer), in river waters with high performance liquid chromatography (HPLC) was developed. FWA in river waters were adsorbed on Sep-pak C18 cartridge and eluted with methanol. The eluate was evaporated to dryness, and the residue was dissolved in acetonitrile-water (3 : 7). The solution was filtrated and analysed by HPLC under the following conditions : column, Inertsil ODS 5 (4.6 mm i.d.×150 mm) ; mobile phase, acetonitrile-0.01 M monobasic sodium phosphate (35 : 65) ; flow rate, 1.0 ml/min ; detections, ultraviolet detector (detection wavelength, 270 nm), fluorescent detector (excitation 345 nm and emission 430 nm). The average recoveries of FWA from river waters at 2-15.6 μg/l were 90-102%. This method was applicable to determine the concentration of 0.01μg/l for FB 351, 0.05μg/l for FB 71 (trans), 0.6μg/l for FB 71 (cis), 0.1μg/l for FB 225 (trans) and 1.1μg/l for FB 225 (cis), respectively, using 100 ml samples. On the basis of the present method applied to samples from 6 different rivers located at Kanagawa prefecture, FB 351 (trans), FB 71 (trans, cis) and FB 225 (trans, cis) were determined.

High-performance liquid chromatographic separation and determination of fluorescent whitening agents in detergents

A simple, rapid, precise and accurate method for determining the fluorescent whitening agents commonly used in detergents is described. The method is based on simple extraction from the detergent by methanol and on direct injection of the extract, without further purification. The extracted whitening agents were separated using a reversed-phase column (RP-18) and by ion-pair formation. The mobile phase was methanol-water (43 + 57) containing 0.005 M triethylammonium chloride, 0.002 5 M sodium acetate and 0.002 5 M acetic acid. Depending on the type of whitening agent present, the determination can be simplified by using methanol-water (1 + 1) as the mobile phase. Fluorimetric detection makes the method highly sensitive and specific.

環境試料中のけい光増白剤の高速液体クロマトグラフィーによる定量

A method of determination of fluorescent whitening agents (FWA) in river waters and sediments by high performance liquid chromatography (HPLC) was studied.Six kinds of FWA could be separated according to following conditions; column : ODS SS-10-B 4mm i.d. X 250mm, mobile phase (a) 0.011 NaH2PO4 -acetonitrile (75 : 25v/v), flowrate : 1.0ml/ min. FWA in the column effluent were monitored with fluorescent detecter (Ex=358nm, Em =403nm).FWA in river waters were adsorbed on SEP PAC cartridge and eluted with methanol. FWA in river sediments were directly extracted by shaking with methanol successively three times. Each extract was evaporated to dryness and dissolved in the solution of water-acetonitrile (70 : 30v/ v) for HPLC.From river waters and sediments of the Sagami river, two types of FWA (FWA I and FWA II), the same as used in the detergents, could be detected. For the rapid quantitative analysis of FWA I and FWA II, it was found to be effective to use mobile phase (b) 0.1% tetraethyl ammonium perchrorate in water-acetonitrile (70 : 30v/v). Then peak heights were linear with FWA amounts in the range of 010ng for FWA I and 01ing for FWA II. By the proposed method, FWA in river waters and sediments of the Sagami river were determined as follows ; FWA I : 0.09-3.4μg/g in sediments, FWA II : 0.85-4.4, μg/l in river waters, 0.1410.7μ g/g in sediments.

Separation and determination of fluorescent whitening agents in detergents by high speed liquid chromatography

Separation and determination of fluorescent whitening agents in detergents by high speed liquid chromatography