Thiết kế hệ thống sục đuổi và bẫy – giải hấp nhiệt kết hợp sắc ký khí đầu dò huỳnh quang nguyên tử để phân tích siêu vi lượng methyl thuỷ ngân=A home – made purge and trap – thermos desorption - gas chromatograph coupled with atomic fluorescence detector for the determination of ultra

Thiết kế hệ thống sục đuổi và bẫy – giải hấp nhiệt kết hợp sắc ký khí đầu dò huỳnh quang nguyên tử để phân tích siêu vi lượng methyl thuỷ ngân=A home – made purge and trap – thermos desorption - gas chromatograph coupled with atomic fluorescence detector for the determination of ultra – trace methylmercury

0 Người đánh giá. Xếp hạng trung bình 0

Tác giả: Quan Thành Huỳnh, Thị Huỳnh Mai Lê, Công Hậu Nguyễn, Văn Đông Nguyễn

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Phát triển Khoa học & Công nghệ: Chuyên san Khoa học Tự nhiên, 2018

Mô tả vật lý:

Bộ sưu tập: Metadata

ID: 473006

Thêm vào giỏ

A hyphenated system for methylmercury based on a gas chromatograph (GC) coupled with an atomic fluorescence spectrometric (AFS) detector equipped with an online purge and trap as a preconcentrator was made. Operating parameters for the whole system were optimized and analytical performances of the system are verified by quality control chart for stability. Organomercurial compounds in an aqueous sample were in-situ ethylated and purged to a trap in-line with a separation device instead of conventional off-line solvent extraction. A 100 mL aqueous sample containing methylmercury in an impinger was mixed with sodium tetraethylborate at pH 5.0. The forming volatile ethylmethylmercury was purged for 30 minutes with the assistance of an Ar flow and trapped into a Tenax sorbent. The trap was then heated to release volatile compounds including ethylmethylmercury into a GC-AFS for separation and detection. The instrumental detection limit was 4.8 pg Hg/L. The method can therefore be applied for the determination of methylmercury in water samples at ultra – trace.Phương pháp xác định methyl thuỷ ngân được nghiên cứu trên hệ thống sắc ký khí đầu dò huỳnh quang nguyên tử với kỹ thuật làm giàu mẫu là sục đuổi và bẫy. Giao diện ghép nối hệ sắc ký khí và đầu dò huỳnh quang nguyên tử được thiết kế lại dựa trên hệ thống đã có sẵn tại phòng thí nghiệm. Các thông số vận hành của toàn bộ hệ thống được tối ưu hoá và hiệu năng phân tích của hệ thống được xác nhận bằng giản đồ kiểm soát chất lượng về độ nhạy. Phương pháp này khác biệt so với các kỹ thuật khác do nó không cần phải chiết bằng dung môi các hợp chất thuỷ ngân hữu cơ ra khỏi dung dịch nước mà chủ yếu dựa vào sự bay hơi nhanh chóng của nó thông qua phản ứng hoá học ngay trong ống impinger. Một lượng nhất định methyl thuỷ ngân được thêm vào bình sục mẫu chứa sẵn khoảng 100 mL nước. Hợp chất methyl thuỷ ngân khó bay hơi sẽ chuyển thành hợp chất ethylmethyl thuỷ ngân dễ bay hơi bằng cách cho phản ứng với sodium tetraethylborate tại môi trường pH 5,0 tạo ra bởi đệm acetate. Phản ứng hoá học này xảy ra ngay trong ống impinger. Hợp chất được tạo dẫn xuất dễ bay hơi này sau đó được sục đuổi bằng dòng khí Ar và được lôi cuốn đến tích góp trên bẫy Tenax trong 30 phút. Kết thúc quá trình tích góp, bẫy được giải hấp nhiệt để dẫn chất phân tích vào hệ thống sắc ký khí cho quá trình định lượng. Giới hạn phát hiện của thiết bị là 4,8 pg Hg/L. Phương pháp có thể được áp dụng để phân tích methyl thuỷ ngân trong các mẫu nước ở hàm lượng siêu vết.

1. Đọc trực tuyến

1. Đọc trực tuyến

Tạo bộ sưu tập với mã QR