This page has only limited features, please log in for full access.

Unclaimed
Ali Alsharif
Department of Chemistry, Faculty of Science, University of Mala, Kuala Lumpur 50603, Malaysia.

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 31 March 2019 in Toxins
Reads 0
Downloads 0

Mycotoxins are common food contaminants which cause poisoning and severe health risks to humans and animals. The present study applied chemometric approach in liquid chromatography-tandem mass spectrometry (LC-MS/MS) optimization for simultaneous determination of mycotoxins, i.e., aflatoxins B1, B2, G1, and G2, and ochratoxin A. The validated quick, easy, cheap, effective, rugged, and safe (QuEChERS)-LC-MS/MS method was used to study the occurrence of mycotoxins in 120 food matrices. The recovery ranges from 81.94% to 101.67% with relative standard deviation (RSD) lesser than 11%. Through the developed method, aflatoxins were detected in raisin, pistachio, peanut, wheat flour, spice, and chili samples with concentration ranges from 0.45 to 16.93 µg/kg. Trace concentration of ochratoxin A was found in wheat flour and peanut samples which ranged from 1.2 to 3.53 µg/kg. Some of the tested food samples contained mycotoxins of above the European legal maximum limit.

ACS Style

Ali Mohamed Ali Alsharif; Yeun-Mun Choo; Guan-Huat Tan. Detection of Five Mycotoxins in Different Food Matrices in the Malaysian Market by Using Validated Liquid Chromatography Electrospray Ionization Triple Quadrupole Mass Spectrometry. Toxins 2019, 11, 196 .

AMA Style

Ali Mohamed Ali Alsharif, Yeun-Mun Choo, Guan-Huat Tan. Detection of Five Mycotoxins in Different Food Matrices in the Malaysian Market by Using Validated Liquid Chromatography Electrospray Ionization Triple Quadrupole Mass Spectrometry. Toxins. 2019; 11 (4):196.

Chicago/Turabian Style

Ali Mohamed Ali Alsharif; Yeun-Mun Choo; Guan-Huat Tan. 2019. "Detection of Five Mycotoxins in Different Food Matrices in the Malaysian Market by Using Validated Liquid Chromatography Electrospray Ionization Triple Quadrupole Mass Spectrometry." Toxins 11, no. 4: 196.

Food analysis
Published: 22 March 2019 in Analytical Letters
Reads 0
Downloads 0

A modified hollow-fiber-supported dispersive liquid-liquid microextraction (HF-DLLME) method was developed for the determination of aflatoxins and ochratoxin A in food samples. The various parameters affecting the efficiency of extraction, such as pH, salt addition, extraction time, stirring rate, desorption time, type and volume of extractant and disperser solvents were carefully studied and optimized using two step strategies. The linearity of the evaluated results was 0.1 to 30 μg L−1 for aflatoxins and 0.1 to 20 μg L−1 for ochratoxin A, with regression coefficients (R2) exceeding 0.9990. The precision was satisfactory with relative standard deviation values less than 11%. The method accuracy was within the recommended range from 70% to 120% and analyte accuracy between 83% and 101%. The limits of detection and quantification were in the range from 0.04 to 0.06 μg L−1 and 0.08 to 0.13 μg L−1, respectively, for multi-aflatoxins, and 0.02 to 0.04 µg L−1 and 0.08 to 0.10 µg L−1, respectively, for ochratoxin A. The developed method was successfully applied for the determination of mycotoxins in food samples.

ACS Style

Ali Mohamed Ali Alsharif; Yeun-Mun Choo; Guan Huat Tan; Lukman Bola Abdulra’Uf. Determination of Mycotoxins Using Hollow Fiber Dispersive Liquid–Liquid–Microextraction (HF-DLLME) Prior to High-Performance Liquid Chromatography – Tandem Mass Spectrometry (HPLC - MS/MS). Analytical Letters 2019, 52, 1976 -1990.

AMA Style

Ali Mohamed Ali Alsharif, Yeun-Mun Choo, Guan Huat Tan, Lukman Bola Abdulra’Uf. Determination of Mycotoxins Using Hollow Fiber Dispersive Liquid–Liquid–Microextraction (HF-DLLME) Prior to High-Performance Liquid Chromatography – Tandem Mass Spectrometry (HPLC - MS/MS). Analytical Letters. 2019; 52 (12):1976-1990.

Chicago/Turabian Style

Ali Mohamed Ali Alsharif; Yeun-Mun Choo; Guan Huat Tan; Lukman Bola Abdulra’Uf. 2019. "Determination of Mycotoxins Using Hollow Fiber Dispersive Liquid–Liquid–Microextraction (HF-DLLME) Prior to High-Performance Liquid Chromatography – Tandem Mass Spectrometry (HPLC - MS/MS)." Analytical Letters 52, no. 12: 1976-1990.

Review
Published: 21 April 2018 in Journal of Chromatographic Science
Reads 0
Downloads 0

Fruits and vegetables constitute a major type of food consumed daily apart from whole grains. Unfortunately, the residual deposits of pesticides in these products are becoming a major health concern for human consumption. Consequently, the outcome of the long-term accumulation of pesticide residues has posed many health issues to both humans and animals in the environment. However, the residues have previously been determined using conventionally known techniques, which include liquid-liquid extraction, solid-phase extraction (SPE) and the recently used liquid-phase microextraction techniques. Despite the positive technological effects of these methods, their limitations include; time-consuming, operational difficulty, use of toxic organic solvents, low selective property and expensive extraction setups, with shorter lifespan of instrumental performances. Thus, the potential and maximum use of these methods for pesticides residue determination has resulted in the urgent need for better techniques that will overcome the highlighted drawbacks. Alternatively, attention has been drawn recently towards the use of quick, easy, cheap, effective, rugged and safe technique (QuEChERS) coupled with dispersive solid-phase extraction (dSPE) to overcome the setback challenges experienced by the previous technologies. Conclusively, the reviewed QuEChERS-dSPE techniques and the recent cleanup modifications justifiably prove to be reliable for routine determination and monitoring the concentration levels of pesticide residues using advanced instruments such as high-performance liquid chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

ACS Style

Abubakar Lawal; Richard Chee Seng Wong; Guan Huat Tan; Lukman Bola Abdulra’Uf; Ali Alsharif. Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC–MS and GC–MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review. Journal of Chromatographic Science 2018, 56, 656 -669.

AMA Style

Abubakar Lawal, Richard Chee Seng Wong, Guan Huat Tan, Lukman Bola Abdulra’Uf, Ali Alsharif. Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC–MS and GC–MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review. Journal of Chromatographic Science. 2018; 56 (7):656-669.

Chicago/Turabian Style

Abubakar Lawal; Richard Chee Seng Wong; Guan Huat Tan; Lukman Bola Abdulra’Uf; Ali Alsharif. 2018. "Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC–MS and GC–MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review." Journal of Chromatographic Science 56, no. 7: 656-669.

Original
Published: 06 April 2018 in Chromatographia
Reads 0
Downloads 0

Pesticides play vital roles in agricultural practices, but the nature and mishandling of the chemicals have led to their accumulation in moist soil, vegetables and fruits. Thus, development of efficient methods for pesticides determination is one of the most important ways to address such challenges. Multivariate response surface methodology optimisation using Placket–Burman and Box–Behnken designs were respectively used for screening and optimisation of significant factors of quick, easy, cheap, effective, rugged and safe (QuEChERS) with dispersive solid-phase extraction (SPE). Consequently, the optimised QuEChERS-dSPE technique coupled with modified ionic liquid-based (IL-based) dispersive liquid–liquid microextraction was used for sample preparation before LC–MS/MS. The developed method was validated (SANTE 11831-2017) for multi-pesticide residues determination in samples of bananas, cabbages, tomatoes, oranges and onions. The precision results were satisfactory in terms of relative standard deviation (≤ 20%) as recommended. The results of accuracy for relative recoveries (82–137%) were satisfactory because 92.5% of results were within the recommended range (70–120%). The matrix effects in all the samples were very weak (less effective) (≤ − 80%). The linearity of the evaluated results was 5–400 µg kg−1 and regression coefficients (R2) were > 0.99. The resulting limits of detection and quantitation were 0.02–0.32 and 0.07–1.06 µg kg−1, respectively, and therefore satisfactory. Certifiably, the estimated measurement uncertainties range (1–16%) was acceptable (≤ 50%). Thus, the developed method could be reliable and suitable for routine determination of multiple pesticide residues in various vegetable and fruit samples.

ACS Style

Abubakar Lawal; Richard Chee Seng Wong; Guan Huat Tan; Lukman Bola Abdulra’Uf; Ali Alsharif. Multi-pesticide Residues Determination in Samples of Fruits and Vegetables Using Chemometrics Approach to QuEChERS-dSPE Coupled with Ionic Liquid-Based DLLME and LC–MS/MS. Chromatographia 2018, 81, 759 -768.

AMA Style

Abubakar Lawal, Richard Chee Seng Wong, Guan Huat Tan, Lukman Bola Abdulra’Uf, Ali Alsharif. Multi-pesticide Residues Determination in Samples of Fruits and Vegetables Using Chemometrics Approach to QuEChERS-dSPE Coupled with Ionic Liquid-Based DLLME and LC–MS/MS. Chromatographia. 2018; 81 (5):759-768.

Chicago/Turabian Style

Abubakar Lawal; Richard Chee Seng Wong; Guan Huat Tan; Lukman Bola Abdulra’Uf; Ali Alsharif. 2018. "Multi-pesticide Residues Determination in Samples of Fruits and Vegetables Using Chemometrics Approach to QuEChERS-dSPE Coupled with Ionic Liquid-Based DLLME and LC–MS/MS." Chromatographia 81, no. 5: 759-768.

Review
Published: 29 November 2016 in Journal of Chromatographic Science
Reads 0
Downloads 0

Hollow fiber liquid-phase microextraction (HF-LPME) techniques coupled to chromatographic systems have been widely used for extraction and determination of diverse compounds. HF-LPME was able to provide better results in precision, accuracy, selectivity and enrichment factor, in addition to reduction of matrix effect and carry over. It is applicable within a wide pH range and compatible with most analytical instruments which enable the utilization of HF-LPME in a wide variety of applications. This review focused on the modified HF-LPME techniques, efficiency, comparison to other LPME methods and applications.

ACS Style

Ali Alsharif; Guan-Huat Tan; Yeun-Mun Choo; Abubakar Lawal. Efficiency of Hollow Fiber Liquid-Phase Microextraction Chromatography Methods in the Separation of Organic Compounds: A Review. Journal of Chromatographic Science 2016, 55, 378 -391.

AMA Style

Ali Alsharif, Guan-Huat Tan, Yeun-Mun Choo, Abubakar Lawal. Efficiency of Hollow Fiber Liquid-Phase Microextraction Chromatography Methods in the Separation of Organic Compounds: A Review. Journal of Chromatographic Science. 2016; 55 (3):378-391.

Chicago/Turabian Style

Ali Alsharif; Guan-Huat Tan; Yeun-Mun Choo; Abubakar Lawal. 2016. "Efficiency of Hollow Fiber Liquid-Phase Microextraction Chromatography Methods in the Separation of Organic Compounds: A Review." Journal of Chromatographic Science 55, no. 3: 378-391.

Review
Published: 01 November 2016 in Journal of AOAC International
Reads 0
Downloads 0

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.

ACS Style

Abubakar Lawal; Guan Huat Tan; Ali Alsharif. Recent Advances in Analysis of Pesticides in Food and Drink Samples Using LPME Techniques Coupled to GC-MS and LC-MS: a Review. Journal of AOAC International 2016, 99, 1383 -1394.

AMA Style

Abubakar Lawal, Guan Huat Tan, Ali Alsharif. Recent Advances in Analysis of Pesticides in Food and Drink Samples Using LPME Techniques Coupled to GC-MS and LC-MS: a Review. Journal of AOAC International. 2016; 99 (6):1383-1394.

Chicago/Turabian Style

Abubakar Lawal; Guan Huat Tan; Ali Alsharif. 2016. "Recent Advances in Analysis of Pesticides in Food and Drink Samples Using LPME Techniques Coupled to GC-MS and LC-MS: a Review." Journal of AOAC International 99, no. 6: 1383-1394.