Arsenic for Environmental Samples content detection method
Technical field
The present invention relates to a kind of Arsenic for Environmental Samples detection method of content, refer to especially the method for high-pressure digestion ICP-AES method mensuration Arsenic for Environmental Samples constituent content.
Background technology
In recent years, morphological analysis has obtained generally paying attention to and developing rapidly.Environmental chemistry man, nutritionist and toxicologist, geochemistry man etc. all admits such fact, and namely the total concentration of element not only is not enough to estimate its toxicity, helpfulness and biological effectiveness, even might mislead.The toxicity of Environmental Trace element and biological effectiveness and migration discharge active closely related with its occurrence status, and the element nature difference of different shape is very large, is determining their behavior and homes to return in environment.Measure the form that element exists in specific sample, could reliably estimate trace element to the impact of environment and ecosystem.Usually, the organic compound of metallic element of the same race due to hydrophobicity and lipophilic feature, makes them can enter biological cycle than corresponding inorganic form toxicity much bigger (except organo-arsenic), inrichment by food chain enters human body, to the health harm.For example the toxicity of the alkylate of Hg, Sn, Pb is much larger than their inorganic form.But the toxicity of inorganic arsenic is larger than organo-arsenic, and the toxicity of the A s (III) in inorganic arsenic is more much bigger than A s (V) again.And for example Cr (III) is human body eubolism indispensable element, and C r (VI) solubleness is large, and activity is higher, the harm heart, kidney and carcinogenic.Thereby needs are distinguished the chemical form of element.
Common Spectrometric Determination Arsenic Content is mainly the atomic fluorescence spectrophotometry technology, and this technology is that specificity is very strong, and the assay method that degree of ripeness is very high has been applied to the detection of arsenic content in industry-by-industry.But seldom adopt now this detection technique abroad, but adopt inductively coupled plasma atomic emissions technology spectroscopic methodology (ICP-AES).Inductively coupled plasma atomic emissions technology is widely applied at industry-by-industry with characteristics such as its high sensitivity that has, pin-point accuracy, multielement simultaneous determinations, developed rapidly in the ultimate analysis field, slowly replacing the traditional element analytical technologies such as atomic absorption spectroscopy (AAS), atomic fluorescence spectrophotometry technology (AFS) and ultraviolet spectrometry spectral technique (UV) becomes main detection technique.In order to integrate with international detection technique, the present invention adopts inductively coupled plasma atomic emissions technology that the As content in environmental sample is measured.
Summary of the invention
Technical matters to be solved by this invention be to overcome the defective of prior art and provide a kind of have detection limit low, detect the method that quick high-pressure digestion ICP-AES method is accurately measured Arsenic for Environmental Samples content.
Technical matters of the present invention is achieved through the following technical solutions:
A kind of high-pressure digestion ICP-MS method is measured the method for Arsenic for Environmental Samples content.
In described ICP-AES method working sample digestion solution, the step of As constituent content is as follows:
(1) take in the high-pressure digestion tank that environmental sample 0.2 g~0.6g is positioned over the 100mL capacity, added 60% liquor potassic permanganate standing 10 minutes, then add concentration 90% nitric acid 10-20mL and concentration 20% hydrogen peroxide 2~5mL to make sample liquid, the high-pressure digestion tank that then sample liquid will be housed is put into air dry oven; Open program control system, set air dry oven and be warming up to 200 ℃~205 ℃, powered-down after constant temperature time 5~10h, naturally cooling; Sample liquid is placed ventilated, limpid to sample liquid, then transfer in 50mL plastics volumetric flask, be settled to 25mL with ultrapure water, obtain Specimen eliminating solution; Directly added 60% liquor potassic permanganate standing 10 minutes in another 100mL high-pressure digestion tank, then add concentration 90% nitric acid 10-20mL and concentration 20% hydrogen peroxide 2~5mL to make sample liquid, the high-pressure digestion tank that then sample liquid will be housed is put into air dry oven; Open program control system, set air dry oven and be warming up to 200 ℃~205 ℃, powered-down after constant temperature time 5~10h, naturally cooling; Sample liquid is placed ventilated, limpid to sample liquid, then transfer in 50mL plastics volumetric flask, be settled to 25mL with ultrapure water, obtain blank digestion solution;
(2) the Specimen eliminating solution that obtains according to step (1) uses inductively-coupled plasma spectrometer, and namely in ICP-AES Instrument measuring Specimen eliminating solution, contained As element in 193.696nm place wave spectrum intensity, records the As intensity level;
(3) configuration standard working solution: taking respectively concentration is the As standard inventory solution of 2.0mg/mL, the standard inventory solution that therefrom takes out 100uL is placed in the 100mL volumetric flask, add 60% liquor potassic permanganate, be diluted to concentration 7% salpeter solution the standard solution mother liquor that concentration is 1.0mg/L, take out respectively again 0uL, 10uL, 20uL, 50uL, 100uL, the described standard solution mother liquor of 200uL is placed in respectively the 10mL volumetric flask, be diluted to respectively standard operation solution with concentration 7% salpeter solution, the 0uL that obtains, 10uL, 20uL, 50uL, 100uL, in the standard operation solution of 200uL, the content of As element corresponds to respectively 0ug/L, 1ug/L, 2ug/L, 5ug/L, 10ug/L, 20ug/L,
(4) configuration inner mark solution: taking concentration is the As standard inventory solution of 1.0mg/mL, and the standard inventory solution that therefrom respectively takes out 100uL is placed in the 100mL volumetric flask, is diluted to concentration 7% salpeter solution the inner mark solution that concentration is 1.0mg/L.
The standard operation solution that (5) will obtain according to step (3) and measuring according to the Specimen eliminating solution that step (1) obtains: Specimen eliminating solution, blank digestion solution that the standard operation solution that step (3) is obtained and step (1) obtain import inductively coupled plasma atomic emission spectrometer, it is the ICP-AES instrument, mix before entering atomizer, select the best isotope of As element to measure; Measure for the first time and add online inner mark solution, first metric works solution, again according to known content and the inductively coupled plasma atomic emission spectrometer of As element in standard operation solution, be the ICP-AES Instrument measuring to As element response draw respectively the standard working curve of As element, then the response of working sample digestion solution and blank each element of digestion solution, calculate the concentration value of blank each element of digestion solution and the concentration value of Specimen eliminating solution A s element according to standard working curve, thereby according to the conventional method calculating concentration value of this area
Inductively-coupled plasma spectrometer in described step (2), running parameter is: radio-frequency power 1000W, plasma gas flow rate 20.0L/min, integral time 20s.Atomizer flow 0.3L/min, assisted gas flow 1.80L/min,
Inductively coupled plasma atomic emission spectrometer in described step (5), running parameter is: radio-frequency power 1000W, carrier gas flux 0.75L/min, complemental air flow 0.2L/min, 2 ℃ of atomization temperatures, be 0.5s integral time, multiplicity 3 times.
High-pressure digestion method by above-mentioned record can well prepare arsenic solution with convenient test.Adopt the ICP-AES method can well solve matrix and disturb, accuracy is high.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the invention are not limited to this.
1, experiment instrument and equipment
100mL high-pressure digestion tank: consisted of by polytetrafluoroethylliner liner and stainless cylinder of steel overcoat
2, the running parameter of experiment instrument and equipment
2.1 inductively coupled plasma atomic emission spectrometer, the i.e. running parameter of ICP-AES instrument:
Radio-frequency power: 1000W
Atomizer flow: 0.3L/min
Assisted gas flow: 1.80L/min
Integral time: 20s
3, experiment agents useful for same
Ultrapure water (self-control)
30% hydrogen peroxide (excellent pure level)
70%, 7% nitric acid (electron level)
the configuration of blank digestion solution: directly add concentration 90% nitric acid 8~14mL and concentration 30% hydrogen peroxide 1~5mL to make sample liquid in 100mL high-pressure digestion tank, tighten cover, then the high-pressure digestion tank of sample liquid will be housed, open program control system, set air dry oven and be warming up to 200 ℃~205 ℃, after constant temperature time 5~10h, powered-down after powered-down, naturally cooling, open cover after end, sample liquid is placed fuming cupboard standing, limpid to sample liquid, then transfer in 25mL plastics volumetric flask, be settled to 25mL with ultrapure water, obtain blank digestion solution, the configuration of standard operation solution: taking concentration is the As element standard inventory solution of 1.0mg/mL, the standard inventory solution that therefrom takes out 100uL is placed in the 100mL volumetric flask, be diluted to concentration 90% salpeter solution the standard solution mother liquor that concentration is 1.0mg/L, take out respectively again 0uL, 10uL, 20uL, 50uL, 100uL, the described standard solution mother liquor of 200uL is placed in respectively the 10mL volumetric flask, be diluted to respectively standard operation solution with concentration 7% salpeter solution, the 0uL that obtains, 10uL, 20uL, 50uL, 100uL, in the standard operation solution of 200uL, the content of As element corresponds to respectively 0ug/L, 1ug/L, 2ug/L, 5ug/L, 10ug/L, 20ug/L,
4. test procedure
4.1 embodiment 1
Taking environmental sample 0.50g is placed in 100mL high-pressure digestion tank, added 60% liquor potassic permanganate standing 10 minutes, then add concentration 90% nitric acid 10-20mL and concentration 20% hydrogen peroxide 2~5mL to make sample liquid, the high-pressure digestion tank that then sample liquid will be housed is put into air dry oven; Open program control system, set air dry oven and be warming up to 200 ℃~205 ℃, powered-down after constant temperature time 5~10h, naturally cooling; Sample liquid is placed ventilated, limpid to sample liquid, then transfer in 50mL plastics volumetric flask, be settled to 25mL with ultrapure water, obtain Specimen eliminating solution.Above-mentioned gained digestion solution is used inductively coupled plasma atomic emission spectrometer, and namely the ICP-AES instrument is measured in digestion solution contained arsenic element in 193.696nm place wave spectrum intensity.
adopt the content of arsenic element in ICP-AES method Fast Measurement digestion solution: at first taking concentration is the As element standard inventory solution of 1.0mg/mL, the standard inventory solution that therefrom takes out 100uL is placed in the 100mL volumetric flask, be diluted to concentration 7% salpeter solution the standard solution mother liquor that concentration is 1.0mg/L, take out respectively again 0uL, 10uL, 20uL, 50uL, 100uL, the described standard solution mother liquor of 200uL is placed in respectively the 10mL volumetric flask, be diluted to respectively standard operation solution with concentration 7 salpeter solutions, the 0uL that obtains, 10uL, 20uL, 50uL, 100uL, in the standard operation solution of 200uL, the content of As element corresponds to respectively 0ug/L, 1ug/L, 2ug/L, 5ug/L, 10ug/L, 20ug/L,
Taking concentration is the arsenic element standard inventory solution of 1.0mg/mL, and the standard inventory solution that therefrom takes out 100uL is placed in the 100mL volumetric flask, is diluted to concentration 7% salpeter solution the inner mark solution that concentration is 1.0mg/L.
Adopt inductively coupled plasma atomic emissions spectrometer, be that the ICP-AES instrument is measured standard operation solution and Specimen eliminating solution: successively with inner mark solution-import inductively coupled plasma atomic emission spectrometer with standard operation solution, Specimen eliminating solution and blank digestion solution, it is the ICP-AES instrument, mix before entering atomizer, select the best isotope of element to measure;
First metric works solution, again according to known content and the inductively coupled plasma atomic emission spectrometer of As element in standard operation solution, be the ICP-AES Instrument measuring to As element response draw respectively the standard working curve of As element, then the response of working sample digestion solution and blank each element of digestion solution, calculate the concentration value of each element of Specimen eliminating solution and the concentration value of blank digestion solution As element according to standard working curve, obtain the content of As according to computing method as known in the art.
The present invention adopts the method for high-pressure digestion to carry out pre-treatment to environmental sample, measure 193.696nm by the ICP-AES method and measure, solved the high-pressure digestion method and cleared up loss and the pollution that not exclusively causes instrument or cause greatly the larger problem of result error because matrix disturbs.Use the ICP-AES standard measure to measure the As element, the detection limit of method is between 0.06~1.5 μ g/kg, and matrix disturbs little, can satisfy the needs of productive life.