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An RP-HPLC-UV method with SPE for cefotaxime in all-in-one total parenteral nutritional admixtures: application to stability studies

Iqbal MS, Bahari MB, Darwis Y, Iqbal MZ, Hayat A, Venkatesh G

J AOAC Int, 2013 6 19;96(2):290-4.
PMID: 23767352

A simple and selective RP-HPLC-UV method with SPE was developed and validated for the quantification of cefotaxime in all-in-one total parenteral nutrition (AIO-TPN) admixtures. Chromatographic separation was achieved on a 5 pm particle size C18 DB column (250 x 4.6 mm id) using the mobile phase ammonium acetate (25 mM, pH 4.0)-50% acetonitrile in methanol (80 + 20, v/v). The flow rate was 0.9 mL/min and the detection wavelength was 254 nm. The analyte was extracted from AIO-TPN admixtures by means of an SPE method. The cefotaxime calibration curve was linear over a concentration range of 100-1400 microg/mL with a correlation coefficient of > or = 0.9994. The intraday accuracy and precision for cefotaxime were < or = -3.15 and < or = 3.08%, respectively, whereas the interday accuracy and precision were < or = -2.48 and < or = 2.25%, respectively. The method was successfully applied to stability studies of cefotaxime in the presence of micronutrients together with low and high concentrations of macronutrients in AIO-TPN admixtures. Cefotaxime was degraded by 13.00 and 26.05% at room temperature (25 +/- 2 degrees C) after 72 h in low and high macronutrient concentration formulations of AIO-TPN admixtures, respectively. The values of cefotaxime degradation rates for low and high macronutrient concentration formulations of AIO-TPN admixtures were -0.164 and -0.353, respectively. These results indicated that there was a higher rate of degradation in the AIO-TPN admixture formulations containing high concentrations of macronutrients.
A practical approach for linearity assessment of calibration curves under the International Union of Pure and Applied Chemistry (IUPAC) guidelines for an in-house validation of method of analysis

Sanagi MM, Nasir Z, Ling SL, Hermawan D, Ibrahim WA, Naim AA

J AOAC Int, 2010 10 7;93(4):1322-30.
PMID: 20922968

Linearity assessment as required in method validation has always been subject to different interpretations and definitions by various guidelines and protocols. However, there are very limited applicable implementation procedures that can be followed by a laboratory chemist in assessing linearity. Thus, this work proposes a simple method for linearity assessment in method validation by a regression analysis that covers experimental design, estimation of the parameters, outlier treatment, and evaluation of the assumptions according to the International Union of Pure and Applied Chemistry guidelines. The suitability of this procedure was demonstrated by its application to an in-house validation for the determination of plasticizers in plastic food packaging by GC.
Comparison of signal-to-noise, blank determination, and linear regression methods for the estimation of detection and quantification limits for volatile organic compounds by gas chromatography

Sanagi MM, Ling SL, Nasir Z, Hermawan D, Ibrahim WA, Abu Naim A

J AOAC Int, 2010 2 20;92(6):1833-8.
PMID: 20166602

LOD and LOQ are two important performance characteristics in method validation. This work compares three methods based on the International Conference on Harmonization and EURACHEM guidelines, namely, signal-to-noise, blank determination, and linear regression, to estimate the LOD and LOQ for volatile organic compounds (VOCs) by experimental methodology using GC. Five VOCs, toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, and styrene, were chosen for the experimental study. The results indicated that the estimated LODs and LOQs were not equivalent and could vary by a factor of 5 to 6 for the different methods. It is, therefore, essential to have a clearly described procedure for estimating the LOD and LOQ during method validation to allow interlaboratory comparisons.
Development of a capillary electrophoresis method for the enantioselective estimation of primaquine in pharmaceutical formulations

Elbashir AA, Saad B, Ali AS, Saleh MI

J AOAC Int, 2008 6 24;91(3):536-41.
PMID: 18567298

A capillary electrophoresis (CE) method has been developed that allows the separation and estimation of primaquine enantiomers using hydroxypropyl-gamma-cyclodextrin (HP-gamma -CD) as a chiral selector. The influence of chemical and instrumental parameters on the separation, such as type and concentration of CD, buffer concentration, buffer pH, applied voltage, capillary temperature, and injection time, were investigated. Good separation of the racemic mixture of primaquine was achieved using a fused-silica capillary (52.5 cm effective length x 50 microm id) and a background electrolyte composed of tris-phosphate buffer solution (50 mM, pH 2.5) containing 15 mM HP-gamma-CD as a chiral selector. The recommended applied voltage, capillary temperature, and injection time were 15 kV, 25 degrees C, and 6 s, respectively. Within-day and interday reproducibility of peak area and migration time gave relative standard deviation values ranging from 1.05-3.30%. Good recoveries (range of 96.8-104.9%) were obtained from the determination of placebos that were spiked with 0.25-1.00 mg/L primaquine. The proposed CE method was successfully applied to the assay of primaquine diphosphate in pharmaceutical formulations (tablets).
Applications of solid-phase microextraction for the analysis of pesticide residues in fruits and vegetables: a review

Abdulra'uf LB, Chai MK, Tan GH

J AOAC Int, 2012 11 28;95(5):1272-90.
PMID: 23175958

This paper reviews the application of various modes of solid-phase microextraction (SPME) for the analysis of pesticide residues in fruits and vegetables. SPME is a simple extraction technique that eliminates the use of solvent, and it is applied for the analysis of both volatile and nonvolatile pesticides. SPME has been successfully coupled to both GC and LC. The coupling with GC has been straightforward and requires little modification of existing equipment, but interfacing with LC has proved challenging. The external standard calibration technique is widely used for quantification, while standard addition and internal or surrogate standards are mainly used to account for matrix effects. All parameters that affect the extraction of pesticide residues from fruits and vegetables, and therefore need to be optimized, are also reviewed. Details of the characteristics of analytical procedures and new trends in fiber production using sol-gel technology and molecularly imprinted polymers are discussed.
Polyvinyl chloride-based membranes for flow injection analysis of quinine in beverages

Saad B, Bee-Leng Y, Saleh MI, Rahman IA, Mansor SM

J AOAC Int, 2001 8 15;84(4):1151-7.
PMID: 11501917

Potentiometric response characteristics were evaluated for quinine selective sensors based on a lipophilic ion-exchanger potassium tetrakis[3,5-bis(trifluoromethylphenyl)]borate (PTFB) immobilized together with plasticizing solvents in polyvinyl chloride membranes. The use of dioctyl phthalate (DOP), 2-nitrophenyl phenyl ether (NPPE), and bis(2-ethylhexyl)adipate (BEHA) plasticizers produced good quality quinine sensors that were sensitive and fast responding, and exhibited near Nernstian responses when used as batch-sensors. These membranes were further tested in a wall-jet flow-through potentiometric flow injection analysis (FIA) detector. Quinine sensors containing BEHA were the most suitable membrane, with no noticeable differences in sensitivity even after 5 h of continuous exposure to solutions. Interference by foreign species such as alkali, alkaline earth metal ions, sugars, and sodium benzoate was minimal in either the batch-mode (log selectivity coefficients
Liquid chromatographic detection of Dowtherm A contamination in oleochemicals and edible oils

Moh FM, Tang TS

J AOAC Int, 1999 8 13;82(4):893-6.
PMID: 10444829

A rapid and direct liquid chromatographic (LC) technique is described for the determination of a eutectic mixture of diphenyl oxide and biphenyl such as Dowtherm A thermal heating fluid (THF) in oleochemicals and palm olein. Analysis is performed with an RP-18 column with fluorescence detection (excitation at 247 nm and emission at 310 nm). The isocratic mobile phase (1.0 mL/min) consists of methanol and water (90 + 10, v/v). A linear calibration model (correlation coefficient = 0.9999) was developed directly from used Dowtherm A THF with the biphenyl peak (4.70 min) as a marker. Average recoveries from spiked glycerin, fatty alcohol mixture, methyl ester mixture, fatty acids, and palm olein were 90.9-108.7%, with a detection limit of 0.1 microgram/mL. The technique requires no prior sample cleanup nor extraction steps and is good for quality assurance purposes.
Determination of shell content in palm kernel cake

Siew WL

J AOAC Int, 1996 1 1;79(1):80-2.
PMID: 8620115

A method for determining shell in palm kernel cake (PKC) is described. This simple and rapid method requires little pretreatment compared with the method currently used in PKC trade, in which the sample undergoes defatting, acid and alkali digestion, and washing, before a chloroform-alcohol solution is used to separate the shells. In the proposed method, only defatting the sample is required. The shells are separated by the density difference between the shell and PKC in a potassium iodide solution. Recoveries of at least 93% were obtained, and the correlation coefficient between the actual shell content and the determined shell content was 0.999, with gradients of 0.97 and 0.98 for fine and coarse shell, respectively.
HPLC-Based Qualitative and Quantitative Analyses of Alkaloids in Chewable Areca Products from Different Geographic Regions

Cao M, Liu Y, Yuan H, Qiu Y, Xie Q, Yi P, et al.

J AOAC Int, 2020 Sep 01;103(5):1400-1405.
PMID: 33241395 DOI: 10.1093/jaoacint/qsaa048

BACKGROUND: Chewable areca products are popular in Asian countries, including India, Pakistan, Malaysia, and China. The major alkaloids present in areca products are guvacine, arecaidine, guvacoline, and arecoline which cause carcinogenicity and addiction.
OBJECTIVE: The objective of this study was the quantitative analysis of the alkaloid content of areca chewable products from different countries and regions using HPLC-UV, as well as the benefit of their safety evaluation products.
METHOD: An HPLC-UV method was established for qualitative and quantitative analyses of 65 batches of areca chewable products from different countries and regions. Additionally, similarity evaluation of chromatographic fingerprints was applied for data analysis.
RESULTS: These results reveal a significant variation in the levels of areca alkaloids among tested products, specifically guvacoline (0.060-1.216 mg/g), arecoline (0.376-3.592 mg/g), guvacine (0.028-1.184 mg/g), and arecaidine (0.184-1.291 mg/g). There were significant differences in the alkaloid content of areca chewable products from different producing areas.
CONCLUSIONS: The method will be useful in the safety evaluation of different areca chewable products.
HIGHLIGHTS: The established HPLC-UV method can be adopted for safety evaluation of areca chewable products from different countries and regions due to its general applicability.
High Throughput Residue Analysis of Indaziflam and its Metabolites in Palm Oil Using Liquid Chromatography-Tandem Mass Spectrometry

Halim N, Kuntom A, Shinde R, Banerjee K

J AOAC Int, 2020 Sep 01;103(5):1237-1242.
PMID: 33241391 DOI: 10.1093/jaoacint/qsaa041

BACKGROUND: Indaziflam (IND) is a herbicide that is used in palm oil plantations for broad spectrum management of weeds. Until now, no validated method has been available for residue estimation of this herbicide in palm oil products.
OBJECTIVE: In this study, we report a rapid method for the residue analysis of IND and its metabolites, viz., IND-carboxylic acid, diaminotriazine, and triazine indanone in a wide range of palm oil matrices using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
METHOD: The optimized sample preparation workflows included two options: (1) acetonitrile extraction (QuEChERS workflow), followed by freezing at -80°C and (2) acetonitrile extraction, followed by cleanup through a C18 solid phase extraction (SPE) cartridge. The optimized LC runtime was 7 min. All these analytes were estimated by LC-MS/MS multiple reaction monitoring.
RESULTS: Both sample preparation methods provided similar method performance and acceptable results. The limit of quantification (LOQ) of IND, IND-carboxylic acid, and triazine indanone was 0.001 mg/kg. For diaminotriazine, the LOQ was 0.005 mg/kg. The method accuracy and precision complied with the SANTE/12682/2019 guidelines of analytical quality control.
CONCLUSIONS: The potentiality of the method lies in a high throughput analysis of IND and its metabolites in a single chromatographic run with high selectivity and sensitivity. Considering its fit-for-purpose performance, the method can be implemented in regulatory testing of IND residues in a wide range of palm oil matrices that are consumed and traded worldwide.
HIGHLIGHTS: This work has provided a validated method for simultaneous residue analysis of indaziflam and its metabolites in crude palm oil and its derived matrices with high sensitivity, selectivity, and throughput.
Direct Analysis of Glyphosate, Glufosinate, and Their Metabolites in Palm Oil Using Liquid Chromatography with Tandem Mass Spectrometry

Shinde R, Halim N, Banerjee AK

J AOAC Int, 2020 Nov 01;103(6):1528-1533.
PMID: 33247748 DOI: 10.1093/jaoacint/qsaa066

BACKGROUND: Glyphosate and glufosinate are broad-spectrum herbicides which are frequently used in palm oil plantations for weed control. Metabolites of these herbicides are known to have environmental and food safety implications. As there is no validated method for multiresidue testing of these herbicides and their metabolites in palm oil products, a new method was needed for the purpose of regulatory analysis.
OBJECTIVE: In this study, we endeavored to develop a rapid method for multiresidue analysis of glyphosate (+aminomethylphosphonic acid) and glufosinate (+3-methylphosphinicopropionic acid and N-acetyl-glufosinate) in refined and crude palm oil matrices using liquid chromatography (LC) tandem mass spectrometry (MS/MS).
METHOD: The optimized sample preparation workflow included extraction of refined or crude palm oil (10 g) with acidified water (0.1 M HCl), cleanup by phase separation with dichloromethane, and analysis by LC-MS/MS with multiple reaction monitoring.
RESULTS: The use of a Torus-DEA LC column ensured simultaneous analysis of these compounds within a runtime of 10 min. The LOQ of these analytes was 0.01 mg/kg, except that of aminomethylphosphonic acid which was 0.02 mg/kg. The method sensitivity complied with the national maximum residue limits of Malaysia and the European Union. Also, the method selectivity, sensitivity, accuracy, and precision were aligned with the SANTE/12682/2019 guidelines of analytical quality control.
CONCLUSIONS: The potentiality of the optimized method lies in a high throughput direct analysis of glyphosate and glufosinate with their metabolites in a single chromatographic run. The method is fit for purpose for regulatory testing of these residues in a broad range of palm oil matrices.
HIGHLIGHTS: The study reports for the first time a validated method for simultaneous analysis of glyphosate, glufosinate, and their metabolites in a range of palm oil products. The method did not require a derivatization step and provided a high throughput analysis of these compounds with satisfactory selectivity, sensitivity, accuracy, and precision.
Use of Carbon Nanotubes for the Analysis of Pesticide Residues in Fruits and Vegetables

Abdulrauf LB, Tan GH

J AOAC Int, 2016 Nov 01;99(6):1415-1425.
PMID: 28206878 DOI: 10.5740/jaoacint.16-0275

This review presents the application of carbon nanotubes as sorbent materials in the analysis of pesticide residues in fruits and vegetables. The advantages, limitations, and challenges of carbon nanotubes, with respect to their use in analytical chemistry, are presented. The efficiency of their application as extraction sorbent materials (in terms of LOD, LOQ, linearity, relative recovery, and RSD) in SPE, solid-phase microextraction, multi-plug filtration clean-up, matrix solid-phase dispersion, and the quick, easy, cheap, effective, rugged and safe method is reported. The synthesis, functionalization, purification, and characterization methods of carbon nanotubes are also discussed.
Recent Advances in Analysis of Pesticides in Food and Drink Samples Using LPME Techniques Coupled to GC-MS and LC-MS: a Review

Lawal A, Tan GH, Alsharif AM

J AOAC Int, 2016 Nov 01;99(6):1383-1394.
PMID: 27667201 DOI: 10.5740/jaoacint.16-0272

Food quality and food safety are major challenges affecting agricultural and industrial aspects of production. Many contaminants from different sources contaminate foods and drinks, leading to disastrous health problems like gene mutations and cancer. Previously, many different methods have been used for the analysis of these contaminants. Liquid-liquid extraction (LLE) has been the most well-known conventional technique used, but its limitations are its tediousness, time required, and the use of large quantities of toxic organic solvents. These limitations have led to the search for other, efficient techniques that are more environmentally friendly. Hence, this review highlights recent advances in liquid-phase (single-drop, hollow fiber, and dispersive liquid-liquid) microextraction procedures for food and drink analyses. Such modifications can be justified for solving limitations associated with the traditional LLE method. The objective of this review is to serve as a reference platform for providing effective management tools for solving problems of pollution, clean-up, and control of food quality and safety globally.
Development of a Simple and Rapid HPLC-UV Method for Simultaneous Determination of Ciprofloxacin Hydrochloride and Oxytetracycline Hydrochloride in Aqueous Matrix

Soon WC, Bin Abdullah AZ, Mohd Din AT

J AOAC Int, 2026 Oct 20.
PMID: 42902795 DOI: 10.1093/jaoacint/qsag096

BACKGROUND: Reliable and effective methods capable of simultaneously determining ciprofloxacin hydrochloride (CIP) and oxytetracycline hydrochloride (OTC) can be useful when concentrations fall within the validated working range.
OBJECTIVE: This study aimed to develop and validate a simple and rapid reversed-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) method for simultaneous determination of CIP and OTC in aqueous matrices.
METHODS: The separation was performed using an Agilent InfinityLab Poroshell 120 EC-C18 column (150 × 4.6 mm, 4 μm) with a mobile phase consisting of 0.1% formic acid and acetonitrile at a flow rate of 1.0 mL/min. The method was validated for linearity, precision, selectivity, recovery, sensitivity, robustness and system suitability. Matrix performance was assessed using fortified lake-water samples.
RESULTS: Linearity over the concentration range of 10-25 mg/L, with R² values of 0.9947 for OTC and 0.9923 for CIP was achieved. The LOD values were 1.40 mg/L for OTC and 1.69 mg/L for CIP, while the corresponding LOQ values were 4.24 and 5.11 mg/L, respectively. Peak-area RSDs were below 1% in both intraday and interday precision studies. Recoveries in fortified lake water ranged from 91.12-109.13% for OTC and 82.88-107.72% for CIP and from 95.84-104.91% and 89.56-112.88%, respectively, in interday analysis. Robustness testing showed that satisfactory chromatographic separation was maintained under the investigated variations in flow rate, column temperature, and detection wavelength.
CONCLUSION: The HPLC-UV approach was applicable for the simultaneous determination of CIP and OTC in aqueous samples containing relatively elevated concentrations of the target antibiotics. The method is not intended for direct trace-level determination in typical environmental waters without an appropriate preconcentration step.
HIGHLIGHTS: A simple RP-HPLC-UV method was developed for the simultaneous determination of CIP and OTC. The method is applicable to aqueous samples containing relatively elevated antibiotic concentrations.

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