Multi-class

S.J. Lehotary, Multi-class, multi-residue analysis of pesticide, strategies for, in Encyclopedia of Analytical Chemistry Instrumentation and Applications, ed. R.A. Meyers, Wiley,... 

Marin JM, Gracia-Lor E, Sancho JV et al (2009) Application of ultra-high-pressure liquid chromatography-tandem mass spectrometry to the determination of multi-class pesticides in environmental and wastewater samples Study of matrix effects. J Chromatogr A 1216 1410-1420... 

In order to prepare the final multi-class predictor map, the input weighted layers are fused using various Fuzzy operators (Fig. 5). Figure 6 is a reclassified final Fuzzy map, predicting the high potential areas for further drilling at East-Kahang. To validate the accuracy of the Fuzzy model, the projected Cu values of the completed drill holes are overlain on the final predictive map. The results show... 

DT Does not make any assumption of the type of relationship between target property and molecular descriptors Models are easy to interpret Fast classification speed Multi-class classification May have over fitting when training set is small and number of molecular descriptors is large Ranks molecular descriptors using information gain which may not be the best for some problems... 

J Weston and C Watkins. Multi-class support vector machines. Technical Report CSD-TR-98-04, University of London, London, UK, 1998. 

Ding, C. H. Dubchak, I. (2001). Multi-class protein fold recognition using support vector machines and neural networks. Bioinformatics 17(4), 349-58. 

Rennie, J. D. M. 2001. Improving multi-class text classification with Naive Bayes. MA thesis. Massachusetts Institute of Technology. 

Venkateswarlu, P., Mohan, K.R., Kumar, Ch.R., and Seshaiah, K. (2007). Monitoring of multi-class pesticide residues in fresh grape samples using liquid chromatography with electrospray tandem mass spectrometry, Food Chem.,105,1760-1766. 

The problem of classification can be extended to multiple classes where an example is assigned to one of several mutually exclusive classes, y e [0,1,...,k where k> 2. An example multi-class classification task is to predict the type of interaction between residue and DNA, which can be broken down into three classes side-chain sugar, side-chain base and none. The training data remains the same as the previous example except the label on each example is now one of these three classes side-chain sugar, side-chain base and none. Another example can be the prediction of proteins with properties of DNA binding, RNA binding, and no binding to nucleic acid. 

BIN Binary classification. MUL Multi-class classification. RNK Ranking. REG Regression. IWC Importance-weighted classification. MIL Multiple-instance Learning. STRUCT Structured-prediction. 

Melvin, I., le, E., Weston, J., Noble, W.S., Leslie, C. Multi-class protein classification using adaptive codes. J. Mach. Learn. Res. 2007, 8,1557-81. 

Nguyen, M.N., Rajapakse, J.C. Two-stage multi-class support vector machines to protein secondary structure prediction. In Pacific Symposium on Biocomputing, 2005, pp. 346-57. 

In 2008, Carretero et al. described a multi-class method for the analysis of 31 antibacterials (including f)-lactams, macrolides, lincosamides, quinolones, sulfonamides, tetracyclines, nitroimidazoles, and trimethoprim) in meat samples by PLE-LC-MS/MS. Meat samples were homogenized and blended with EDTA-washed sand, then extracted with water by applying 1500 psi (Ib/in. ), at 70°C. One extraction cycle was 10 min. A drawback of the method is the large volumes of extracts (40 ml) obtained, which required evaporation to concentrate the extract volume prior to final analysis. This evaporation step considerably increases the time required for sample preparation. The proposed method has been applied to the analysis of 152 samples of cattle and pig tissues, with the presence of quinolones, tetracyclines, and sulfonamides detected in 15% of the samples, although at concentrations below the MRLs. 

Typical SPE sorbents used for multi-class antibiotic analysis in food matrices include Oasis HLB (hydrophilic-lipophilic balanced) and Strata X. Oasis HLB cartridges have been preferred in many laboratories because of their good retention properties and highly reproducible recoveries of a wide range of compounds, whether polar or non-poiar (due to their combined hydrophobic-hydrophiclic retention mechanism). Strata X cartridges, which are similar in functionality to Oasis HLB cartridges, provide comparable results. 

Among the multi-class methods reported in the literature, a procedure that involves sample dissolution with EDTA under mildly acidic conditions (pH 4.0) followed by SPE with Oasis HLB cartridges has been applied for the simultaneous analysis of macroiides, tetracyclines, quinolones, and sulfonamides in honey samples Separation and determination by UPLC-MS/MS enabled the analysis of 17 compounds in <5 min. Mean recoveries ranged from 70% to 120%, except for three compounds (doxycycline, erythromycin, and tilmicosin), which had recoveries of >50%. Application of the method to the analysis of honey samples obtained from different beekeepers and local supermarkets... 

Turnipseed et al. described a method for the multi-class residue determination of P-Iactams, sulfonamides, tetracyclines, fluoroquinolones, and macroiides in milk and other dairy products. The sample preparation combines extraction with acetonitrile, clean-up with Oasis HLB cartridges, and ultrafiltration using molecular weight cut-off filters to improve the overall performance of the analysis. Acceptable recoveries were obtained for sulfanomides, macroiides, and quinolones (>70%) however, recoveries were rather low for tetracyclines (50-60%) and P-lactams (<50%). Despite the extensive clean-up procedure, significant matrix ion suppression was observed for many compounds, making it necessary to include matrix-matched calibration standards for quantification purposes. 

A high-throughput method that combines on-line extraction and determination by LC-MS/MS has been developed for the screening of 13 multi-class antibacterials (macrolides, fluoroquinolones, lincosamides, and trimethoprim) in different animal muscle tissues. After sample deproteinization with acetontirile, the extracts were directly loaded onto the SPE cartridge, packed with an Oasis HLB... 

TABLE 4.1 Summary of Sample Preparation Procedures for Determination of Multi-class Antibiotics in Food Samples... 

Moreno-Bondi MC, Marazuela MD, Herranz S, Rodriguez E, An overview of sample preparation procedures for LC-MS multi-class antibiotic determination in environmental and food samples. Anal. Bioanal. Chem. 2009 395 921-946. 

Chico J, Rubies A, Centrich F, Companyo R, Prat MD, Granados M, High-throughput multi-class method for antibiotic residue analysis by liquid chromatography-tandem mass spectrometry, J. Chromatogr. A 2008 1213 189-199. 

De Alwis H, Heller DN, Multi-class, multi-residue method for the detection of antibiotic residues in distillers grains by liquid chromatography and ion trap tandem mass spectrometry, J. Chromatogr. A 2010 1217 3076-3084. 

Turnipseed SB, Andersen WC, Karbiwnyk CM, Madson MR, Miller KE, Multi-class, multi-residue liquid chromatog-raphy/tandem mass spectrometry screening and confirmation methods for drug residues in milk. Rapid Commun. Mass Spectrom. 20008 22 1467-1480. 

Heller D, Nochetto CB, Rumel NG, Thomas MH, Development of multi-class methods for drug residues in eggs hydrophilic solid-phase extraction clean-up and liquid chro-matography/tandem mass spectrometry analysis of tetracycline, fluoroquinolone, sulfonamide, and -lactam residues, J. Agric. Food Chem. 2006 54 5267-5278. 

Tang HP, Ho C, Lai SS, High-thronghput screening for multi-class veterinary drug residues in animal muscle using... 

Lopez Ml, Barton JS, Chu PS, Multi-class determination and confirmation of antibiotic residues in honey using LC-MS/MS, J. Agric. Food Chem. 2008 56 1553-1559. 

There are a few aspects that need to be considered when developing an LC-MS multi-class method ... 

Ultra-high-performance liquid chromatography has been increasingly used for the determination of multi-residue or multi-class antibiotics in food (Table 6.1). For example, an UHPLC/ESI-MS/MS method was reported to simultaneously analyze 17 different veterinary drug residues belonging to several classes of antibiotics such as macrolides, tetracyclines, quinolones, and sulfonamides... 

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