CN104535509A - Method for qualitative detection of hogwash oil - Google Patents

Abstract

The invention discloses a method for qualitative detection of hogwash oil. The method comprises the steps of detecting sodium dodecylbenzene sulfonate in a sample by adopting a methylene blue spectrophotometry, wherein the sample of which the content of sodium dodecylbenzene sulfonate is more than 1 microgram/mL is hogwash oil. The method disclosed by the invention is simple, capable of effectively identifying the hogwash oil, and is of great significance in restraining waste oil to return to the market.

Description

A kind of method of qualitative detection hogwash fat

Technical field

The present invention relates to a kind of method of qualitative detection hogwash fat.

Background technology

Hogwash fat is that the grease contained by catering trade waste residue is separated through pulp water, fishes for oil reservoir, and the grease then obtained through processing process such as dehydration, decolourings is rotten grease.Because grease interacts with some house refuses such as sewage, washing agent, heavy metal, microorganism in use and waste procedures, produce harmful material, simple refining processing can not to remove in grease the harmful chemical components such as impurity at all completely, if will to healthy generation great damage as edible oil, now studies have found that grease can produce trans-fatty acid when high-temperature heating, large quantity research confirms the effect of the health risks such as trans-fatty acid can increase the probability suffered from a heart complaint, Developing restraint growth.

At present GB2716-2005 edible vegetable oil hygienic standard is mainly relied on to grease superior and inferior evaluating standard, the moisture, acid value, peroxide value, carbonyl valency, iodine number, arsenic, aflatoxin B1, benzo (a) pyrene etc. of grease are detected.But lawless person mixes pseudo-technology quite maturation, if waste grease is processed through refining, is only difficult to judge that whether grease is qualified by these indexs.In order to effectively contain spreading unchecked of waste oil, guarantee the healthy of numerous people, be necessary the discrimination method of waste grease processed, supplementing as edible oil national standard, help supervision department and consumer to reflect waste grease, therefore, the waste grease physical and chemical index that different method for refining obtains is analyzed, work out the method for effective analysis and identification waste grease, help relevant department's containment waste grease backflow market to have very important meaning.

Summary of the invention

The technical problem to be solved in the present invention overcomes existing defect, provides a kind of method of qualitative detection hogwash fat.

In order to solve the problems of the technologies described above, the invention provides following technical scheme:

A method for qualitative detection hogwash fat, comprise the neopelex adopted in MBAS spectrophotometry detection sample, the sample that sodium dodecyl benzene sulfonate content is greater than 1 μ g/mL is hogwash fat.

Further, the testing process of described neopelex is as follows:

(1) samples with water ultrasound wave is stirred extraction, be separated to obtain aqueous phase;

(2) regulate aqueous phase to neutral, add methenyl choloride and methylene blue solution, jolting is quenched and is got, and methenyl choloride uses sulfuric acid scrubbing mutually;

(3) detect the absorbance of methenyl choloride phase at 650nm place, calculated the content of neopelex in sample by neopelex concentration-absorbance typical curve.

The inventive method is simple, effectively can identify hogwash fat, has very important meaning for containment waste grease backflow market.

Embodiment

Below the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein is only for instruction and explanation of the present invention, is not intended to limit the present invention.

Take oil sample 10.0g, the ultrasound wave that adds water stirs and extracts, and 25 mL color comparison tubes are put in water intaking mutually 5 mL, and with phenolphthalein indicator, regulate alkalescence with 4% sodium hydroxide solution, 3% sulfuric acid solution is adjusted to neutrality.Add methenyl choloride and methylene blue solution, jolting layering, get methenyl choloride layer, with 3% sulfuric acid solution cleansing solution washing.Strip 3 times through methenyl choloride, merge methenyl choloride, be settled to 25 mL, measure at 650nm place with spectrophotometer.The content of neopelex in each sample oil is calculated by the neopelex typical curve set up and standard equation.

Get 0.5 respectively, 1.0,1.5,2.0,2.5, the neopelex standard solution of 3.0mg/L is in 25mL color comparison tube, add two phenolphthalein, regulate alkalescence with 4% sodium hydroxide solution, 3% sulfuric acid solution is adjusted to neutrality, add methenyl choloride and methylene blue solution, fierce jolting 0.5min, places layering, gets methenyl choloride layer, 3 times are repeatedly extracted through methenyl choloride, merge methenyl choloride, be settled to 25mL, measure absorbance with spectrophotometer at 650nm place.Obtaining regression equation y=0.192x-0.0027, x is absorbance, and y is the concentration of neopelex, coefficient R ²=0.9947.

Adopt standard addition method, respectively to the neopelex standard solution adding 1.00,3.00,5.00,10.00 μ g/mL in qualified edible oil extract, each horizontal parallel surveys 6 times, experimental result shows, the recovery of this method is 95 ~ 96%, relative standard deviation (RSD) is 2.6% ~ 4.7%, and measurement result meets analyzes requirement.

In various different sample oil, the content of neopelex (SDBS) is as follows

。

From testing result, no matter through which kind of process, the neopelex in hogwash fat is all obvious far above qualified edible oil.Therefore, the inventive method can as the detection method of Qualitive test hogwash fat and qualified edible oil, namely can be judged to be hogwash fat when the SDBS content of sample oil is greater than 1 μ g/mL.

Obtain hogwash fat respectively by different restaurant, obtain the oil sample of different disposal through following process:

(1) raw oil: by the swill floating thing fished for as in 1000mL beaker, with heating by electric cooker, maintain about 100 DEG C, heating is about after one hour, with the impurity that two-layer filtered through gauze removing is larger, then stratification, gets upper strata oil, lower floor, still containing more grease, adds in heating next time and continues to be separated.Merge oil reservoir and obtain raw oil.

(2) washing oil: the rough hogwash fat after heating and filtering is shaken up, takes 100g oil sample in 250mL beaker, add the distilled water of equal volume, as in 80 DEG C of water-baths, frequently stir (stir unsuitable violent, prevent emulsion from occurring), take out after 20min, transfer in separating funnel, discard lower aqueous layer after layering, get upper strata oil, repeat above operation twice, three times altogether, oil must be washed.

(3) alkali refining oil: slowly add the sodium hydroxide solution taken while stirring, Non-follow control stirring rate 60r/min, stir not easily violent.Neat soap is kept to 30r/min after occurring, after adding NaOH, bath switch of fetching boiling water, starts heating, and 60 DEG C of insulations leave standstill 12h(or directly turn off water-bath spends the night).Get upper strata oil, isolate soap stock (precipitation) and discard.Oil is heated to 75 DEG C of distilled water washings that 60 DEG C add volume fraction 20 ~ 30%, slowly stirs (preventing emulsification), transfer to after 30min in separating funnel, discard lower layer of water, wash 3 times altogether.

(4) refined oil: get alkali refining hogwash fat, takes out after reacting 20min, two-layer gauze suction filtration twice with the activated charcoal of massfraction 3% in 65 DEG C of water-baths.

Last it is noted that the foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, although with reference to previous embodiment to invention has been detailed description, for a person skilled in the art, it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (2)

1. a method for qualitative detection hogwash fat, comprise the neopelex adopted in MBAS spectrophotometry detection sample, the sample that sodium dodecyl benzene sulfonate content is greater than 1 μ g/mL is hogwash fat.

2. the method for qualitative detection hogwash fat according to claim 1, it is characterized in that, the testing process of described neopelex is as follows:

(1) samples with water ultrasound wave is stirred extraction, be separated to obtain aqueous phase;

(2) regulate aqueous phase to neutral, add methenyl choloride and methylene blue solution, jolting is quenched and is got, and methenyl choloride uses sulfuric acid scrubbing mutually;

(3) detect the absorbance of methenyl choloride phase at 650nm place, calculated the content of neopelex in sample by neopelex concentration-absorbance typical curve.