Determination of Moisture by Mid Infrared Transmission Spectroscopy

1988 ◽  
Vol 71 (5) ◽  
pp. 1024-1027 ◽  
Author(s):  
Frederick R Van De Voort ◽  
Marilou Laureano ◽  
James P Smith

Abstract An investigation was undertaken to determine whether commercially available mid infrared filter instrumentation (i.e., Multispec MK1) could be used to determine moisture in a manner similar to the AOAC near infrared method. Using a specially designed IR scanning spectrophotometer capable of working with aqueous systems, functional sample (6.02 jtm) and reference (5.56 iim) wavelengths were determined for quantitating water-methanol mixtures, and a standard curve was derived. Skim milk powder, bread crumbs, and flour were mixed with dry methanol to extract moisture into the solvent; moisture was quantitated relative to 3 AOAC methods. The results indicated that the wavelength pair selected worked well and had the potential to determine moisture content of low moisture food products, given that appropriate moisture extraction protocols were derived. This work indicates that the capabilities of commercial filter-based mid infrared instruments could be expanded to include moisture analyses if such instruments were equipped with the appropriate interference filters to carry out this determination.

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.


2016 ◽  
Vol 99 (1) ◽  
pp. 198-203
Author(s):  
Wu Bolong ◽  
Zhang Fengxia ◽  
Ma Xiaoning ◽  
Zhou Fengjuan ◽  
Sharon L Brunelle

Abstract A potentiometric method for determination of chloride was validated against AOAC Standard Method Performance Requirement (SMPR®) 2014.015. Ten AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1849a, were tested in duplicate on 6 independent days. The repeatability (RSDr) ranged from 0.43 to 1.34%, and the intermediate reproducibility (RSDiR) ranged from 0.80 to 3.04%. All results for NIST SRM 1849a were within the range of the certified concentration (701 ± 17 mg/100 g). Recovery was demonstrated with two overspike levels, 50 and 100%, in the 10 SPIFAN matrixes. Samples were tested in duplicate on 3 different days, and all results were within the SMPR requirement of 95 to 105%. The LOQs of the method for powdered products and ready-to-feed or reconstituted products were 20 mg/100 g and 2.2 mg/100 mL, respectively. A wide analytical range from the LOQ to 99.5% chlorine content can be reached with an appropriate dilution factor, but in practice, the upper analytical value observed in routine matrix testing was approximately 1080 mg/100 g in skim milk powder. This is a rapid, simple, and reliable chlorine-testing method applicable to infant formula, adult nutritionals, and ingredients used in these dairy-based products, such as skim milk powder, desalted whey powder, whey protein powder, and whole milk powder.


1984 ◽  
Vol 67 (1) ◽  
pp. 49-51
Author(s):  
Huguette Cohen ◽  
Michel Lapointe ◽  
Jean Marc Fremy

Abstract A liquid chromatographic (LC) method is proposed for the determination of aflatoxin Mi in milk. The method was successfully applied to both liquid whole and skim milk and also whole and skim milk powder. The samples are initially extracted with acetonitrile–water followed by purification using a silica gel cartridge and a C18 cartridge. Final analysis by LC was achieved using a radial compression module equipped with a 5 μm C18 column and a fluorescence detector. The method was successfully applied to samples at levels of 10 to 0.08 ppb added aflatoxin Mi with recoveries in the range of 70–98%.


2015 ◽  
Vol 8 (8) ◽  
pp. 2125-2134 ◽  
Author(s):  
Edoardo Capuano ◽  
Rita Boerrigter-Eenling ◽  
Alex Koot ◽  
Saskia M. van Ruth

2005 ◽  
Vol 6B (11) ◽  
pp. 1101-1106 ◽  
Author(s):  
Rong-fa Guan ◽  
Dong-hong Liu ◽  
Xing-qian Ye ◽  
Kai Yang

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